* Morries Mena * Springer Specialist Surgery Series Other titles in this series include:

Upper Gastrointestinal Surgery, edited by Fielding & Hallissey, 2005 Neurosurgery: Principles and Practice, edited by Moore & Newell, 2004 Transplantation Surgery, Edited by Hakim & Danovitch, 2001 Alun H. Davies and Colleen M. Brophy (Eds)

With 46 Illustrations Alun H. Davies, MA, DM, FRCS Colleen M. Brophy, MD, FACS Department of Vascular Surgery Chief of Vascular Surgery Reader and Honorary Consultant in Surgery Carl T. Hayden VAMC Imperial College London Research Professor Bioengineering Charing Cross Hospital Arizona State University London, UK Clinical Professor of Surgery University of Arizona Phoenix, AZ USA

A catalogue record for this book is available from the British Libuary

Library of Congress Control Number: 2005923614

ISBN-10: 1-85233-288-3 Printed on acid-free paper. ISBN-13: 978-1-85233-288-4

© Springer-Verlag London Limited 2006 Apart from any fair dealing for the purposes of research or private study, or criticism, or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or trans- mitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms of licenses issued by the Copyright Licensing Agency. Inquiries concerning reproduction outside those terms should be sent to the publishers. The use of registered names,trademarks,etc,in this publication does not imply,even in the absence of a specific statement,that such names are exempt from the relevant laws and regulations and therefore free for general use. Product liability: The publisher can give no guarantee for information about drug dosage and application thereof contained in this book. In every individual case the respective user must check its accuracy by con- sulting other pharmaceutical literature.

Printed in the United States of America. (BS/MVY)

987654321

Springer Science+Business Media springeronline.com Preface

This book provides coverage of a broad range of topics in the field of vascular surgery to residents, registrars in training, and to recent graduates of training programs. The book is meant to be a practical rendition of the basic knowledge and clinical management required for optimal care of vascular surgical patients. Each chapter contains input from specialists in vascular surgery from the United States and Great Britain. There are up- to-date perspectives on common clinical conditions and emerging techniques encoun- tered by vascular surgeons from both an American and British perspective. The chapters are organized under broad topics including medical management, noninvasive and inva- sive diagnostic approaches, perioperative care, indications and approaches for vascular procedures, and a discussion of newer endovascular techniques. The information con- tained in this text is not meant to be exhaustive, but rather a practical overview that will be useful in directing the management of patients with vascular diseases. The informa- tion in this text is also meant to be useful for certification examinations and recent grad- uates of vascular surgical training programs can utilize this text as an update of the most important vascular topics.

Alun H. Davies Colleen M. Brophy

v Contents

Preface ...... v Contributors ...... ix

1. The Epidemiology and Etiology of Paul B. Kreienberg, R. Clement Darling III, and F.G.R. Fowkes ...... 1

2. Clinical Evaluation of Patients with Vascular Disease William G. Tennant ...... 9

3. Noninvasive Vascular Examination Colleen M. Brophy ...... 19

4. Radiological Investigations Steven M. Thomas, Kong T. Tan, and Mark F. Fillinger ...... 25

5. Bleeding and Clotting Disorders Vivienne J. Halpern and Frank C.T. Smith ...... 39

6. Medical Management of Peripheral Arterial Disease Jill J.F. Belch and Andrew H. Muir ...... 53

7. Anesthesia for Vascular Surgery Jamal J. Hoballah and Farid Moulla ...... 65

8. Nonatherosclerotic Vascular Disease Jonathan R.B. Hutt and Alun H. Davies ...... 73

9. Lower Limb Rajabrata Sarkar and Alun H. Davies ...... 91

vii viii

CONTENTS

10. Chronic Venous Insufficiency, Varicose , Lymphedema, and Arteriovenous Fistulas Andrew W. Bradbury and Peter J. Pappas ...... 105

11. Vascular Trauma Kathleen J. Ozsvath, R. Clement Darling III, Laila Tabatabai, Sacha Hamdani, Alun H. Davies, and Meryl Davis ...... 125

12. Complications in Vascular Surgery Jeremy S. Crane, Nicholas J.W. Cheshire, and Gilbert R. Upchurch, Jr...... 133

13. David C. Mitchell and C. Keith Ozaki ...... 141

14. Outcome Measures in Vascular Surgery Christopher J. Kwolek and Alun H. Davies ...... 149

15. Carotid Disease A. Ross Naylor, Peter H. Lin, and Elliot L. Chaikof ...... 155

16. Arch Vessel,Vertebrobasilar, and Upper Extremity Eva M. Rzucidlo and A. Ross Naylor ...... 181

17. Aneurysmal Disease Philip Davey and Michael G. Wyatt ...... 191

18. Renovascular and Ischemic Nephropathy Sherry D. Scovell ...... 221

19. Visceral Ischemic Syndromes George Geroulakos, Peter A. Robless, and William L. Smead ...... 231

20. Endovascular Approaches and Techniques Steven M. Thomas, Kong T. Tan, and Mark F. Fillinger ...... 237

Index ...... 253 Contributors

Jill J.F. Belch, MB ChB, MD, FRCP Philip Davey, MB ChB Peripheral Vascular Diseases Research Unit, Newcastle upon Tyne, UK Department of Medicine, Ninewells Hospital and Medical School, Dundee, UK Alun H. Davies, MA, DM, FRCS Department of Vascular Surgery, Reader and Honorary Consultant in Surgery, Imperial Andrew W. Bradbury, BSc, MB ChB, MD, FRCS College, Charing Cross Hospital, London, UK University Department of Vascular Surgery, London Research Institute, Birmingham Heartlands Hospital, Birmingham, UK Meryl Davis Charing Cross Hospital, London, UK Colleen M. Brophy, MD, FACS Chief of Vascular Surgery, Carl T. Hayden Mark F. Fillinger, MD, FACS VAMC,Research Professor Bioengineering Department of Vascular Surgery, Dartmouth Arizona State University, Clinical Professor of Medical School, Dartmouth-Hitchcock Surgery, University of Arizona, Phoenix, AZ, Medical Center, Lebanon, NH, USA USA F.G.R. Fowkes, MB ChB, PhD, FRCPE, FFPHM Wolfson Unit for Prevention of Peripheral Elliot L. Chaikof, MD, PhD, FACS Vascular Diseases, Public Health Sciences, The Division of Vascular Surgery, Brown University of Edinburgh, Edinburgh, UK Whitehead Department of Surgery, Emory University School of Medicine, Atlanta, GA, George Geroulakos, MD, FRCS, DIC, PhD USA Vascular Unit, Ealing Hospital, London, UK

Vivienne J. Halpern, MD, FACS Nicholas J.W. Cheshire, MB ChB, MD, FRCS Department of Surgery, Division of Vascular Regional Vascular Unit, St Mary’s Hospital, Surgery, Long Island Jewish Medical Center, London, UK New Hyde Park, NY, USA

Jeremy S. Crane, MB ChB, MRCS Sacha Hamdani Regional Vascular Unit, St Mary’s Hospital, Institute for Vascular Health and Disease, London, UK Albany Medical Center, Albany, NY, USA Jamal J. Hoballah, MD R. Clement Darling III, MD Department of Surgery, Division of Vascular Institute for Vascular Health and Disease, Surgery, University of Iowa Hospitals and Albany Medical Center, Albany, NY, USA Clinics, Iowa City, IA, USA

ix x

CONTRIBUTORS

Jonathan R.B. Hutt, BA, MBBS Peter A. Robless, MB ChB, FRCS, MD, FEBVS Department of Accident and Emergency, Department of Cardiac, Thoracic and Vascular Imperial College, Charing Cross Hospital, Surgery, National University Hospital, London, UK Singapore, Republic of Singapore

Paul B. Kreienberg, MD Eva M. Rzucidlo, MD Institute for Vascular Health and Disease, Department of Vascular Surgery, Dartmouth- Albany Medical Center, Albany, NY, USA Hitchcock Medical Center, Lebanon, NH, USA Christopher J. Kwolek, MD, FACS Division of Vascular Surgery, Massachusetts Rajabrata Sarkar, MD, PhD General Hospital, Boston, MA, USA Division of Vascular Surgery, University of California, San Francisco, CA, USA Peter H. Lin, MD, FACS Division of Vascular Surgery and Sherry D. Scovell, MD Endovascular Therapy, Michael E. DeBakey Division of Vascular Surgery, Beth Israel Department of Surgery, Baylor College of Deaconess Medical Center, Boston, MA, USA Medicine, Houston, TX, USA William L. Smead, MD David C. Mitchell, MA, MS, FRCS Division of General Vascular Surgery, Ohio Department of Surgery, Southmead Hospital, State University, Columbus, OH, USA North Bristol NHS Trust, Bristol, UK Frank C.T. Smith, BSc, MD, FRCS Farid Moulla, MD, MBA University Department of Surgery, University Department of Anaesthetics, Charing Cross of Bristol, Bristol Royal Infirmary, Bristol, UK Hospital, London, UK Laila Tabatabai Andrew H. Muir, MB ChB Institute for Vascular Health and Disease, Peripheral Vascular Diseases Research Unit, Albany Medical Center, Albany, NY, USA Department of Medicine, Ninewells Hospital and Medical School, Dundee, UK Kong T. Tan, MB ChB, BAO, FRCSI, FRCR Sheffield Vascular Institute, Vascular Office, A. Ross Naylor, MB ChB, MD, FRCS Northern General Hospital, Sheffield, UK Department of Vascular Surgery, Leicester Royal Infirmary, Leicester, UK William G. Tennant, BSc, MB ChB, MD, FRCS Department of Vascular Surgery, Queens C. Keith Ozaki, MD, FACS Medical Centre, Nottingham, UK Division of Vascular Surgery and Endovascular Therapy, University of Florida Steven M. Thomas, MRCP, FRCR, MSc College of Medicine, Gainesville, FL, USA Sheffield Vascular Institute, Vascular Office, Northern General Hospital, Sheffield, UK Kathleen J. Ozsvath, MD Institute for Vascular Health and Disease, Gilbert R. Upchurch, Jr., MD Albany Medical Center, Albany, NY, USA Surgery Department, Vascular Surgery Section, University of Michigan Health Peter J. Pappas, MD System, Ann Arbor, MI, USA Department of Surgery, Section of Vascular Surgery, University of Medicine and Dentistry Michael G. Wyatt, MB BS, MSc, MD, FRCS of New Jersey – New Jersey Medical School, Department of Vascular Surgery, Freeman Newark, NJ, USA Hospital, Newcastle upon Tyne, UK 1 The Epidemiology and Etiology of Atherosclerosis Paul B. Kreienberg, R. Clement Darling III, and F.G.R. Fowkes

The underlying disorder in the vast majority of representing approximately 16% of all deaths. In cases of is atherosclero- the United States cardiovascular disease is the sis, for which low-density lipoprotein (LDL) most common cause of mortality in both men is recognized as a major risk factor. and women and accounts for almost 500,000 Evidence from epidemiological and clinical deaths/year. Additionally, 58,800,000 Americans studies continues to improve our understanding have one or more types of cardiovascular of the pathogenesis of atherosclerosis. Athero- disease according to current estimates (Table sclerosis contributes to myocardial infarction, 1.1). stroke, and peripheral vascular disease. Despite Coronary artery disease (CAD) has been rec- major advances in the development of diagnos- ognized as the leading cause of death since the tic methods and effective treatments, cardiovas- late 1940s. Hypertension, hypercholesterolemia, cular disease remains the leading cause of cigarette smoking, and diabetes mellitus were mortality in the Western world. identified as key contributors to atherosclerosis Vascular surgeons treat patients who have and the development of cardiovascular risk. already developed end-stage cardiovascular These risk factors are also related to cere- disease. These surgeons have a unique opportu- brovascular and peripheral vascular disease nity to intervene not only in the arterial pathol- (Table 1.2). ogy itself, but also in the main factors that The data support aggressive treatment of ath- contribute to the development of atherosclero- erosclerosis in populations at risk. In patients sis.Atherosclerosis is a systemic disorder and all with peripheral arterial disease (PAD), there aspects of the disease must be addressed in is a high prevalence of myocardial infarction, treating these patients. stroke, and increased mortality. Lack of patient and physician awareness of peripheral vascular disease is associated with low atherosclerosis Epidemiology risk factor treatment intensity (Sueta et al., 1999). In this study of patients with known Cardiovascular disease is responsible for cardiovascular disease, only 35% had smoking approximately 30% of all mortality worldwide, behavior treated, 73% had lipid abnormal- amounting to approximately 15 million deaths ities treated, and 71% were on antiplatelet (Sueta et al., 1999). Furthermore, cardiovascular therapy. Recognition and treatment in patients disease is the principal cause of mortality in all with symptomatic or asymptomatic [ankle– developed countries, responsible for 50% of all brachial index (ABI) <0.9] PAD were deaths, and is also emerging as a prominent significantly lower than the rates for patients public health problem in developing countries, with CAD.

1 2

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Table 1.1. Cardiovascular Disease in the United States: a minimal effect in improving walking distance 58.8 million Americans have one or more types of in claudicants. cardiovascular disease Type Number (in millions) Hypertension 50 Hyperlipidemia Coronary artery disease 12 An estimated 50% of American adults have total Stroke 4.4 Congestive heart failure 4.6 blood cholesterol levels of 200mg/dL and Peripheral arterial disease 8.4 higher, and about 20% of American adults have levels of 240mg/dL or higher. Levels of 240mg/dL or higher are considered high risk and levels from 200 to 239mg/dL are considered Table 1.2. Selected risk factors for atherosclerosis borderline high risk. Evidence linking lipids to atherosclerosis has grown, suggesting that low- Age ering serum cholesterol, whether through diet Diabetes and lifestyle modification alone or in combina- Smoking Hyperlipidemia tion with cholesterol-lowering pharmacother- Hypertension apy, decreases the incidence of vascular events. Hyperhomocystinemia For example a 1mg/dL increase in high-density Hyperfibrinogenemia lipoprotein (HDL) cholesterol concentration is associated with a 2% to 3% decrease in CAD and a 4% to 5% decrease in cardiovascular mortal- ity. Data from the Multiple Risk Factor Inter- vention Trial (MRFIT) demonstrate a strong, Risk Factors graded, positive correlation between serum cholesterol and cardiovascular mortality rate Smoking (Neaton and Wentworth, 1992). Elevations in lipoprotein (a) [Lp(a)] constitute a more Nearly 440,000 Americans die each year of recently recognized independent risk factor smoking-related illness, at a cost of about $50 for cardiovascular disease. Elevations of LP(a) billion annually. In general, smoking is associ- greater than 30mg/dL increase the risk of CAD ated with a threefold increase in the risk for approximately twofold (Beckman et al., 2002). peripheral atherosclerosis (Hiatt et al., 1995). Two large follow-up studies of patients with intermittent demonstrate the Diabetes benefits of smoking cessation (Jonason and Bergstrom, 1987; Smith et al., 1996). In these Diabetes mellitus magnifies the risk of cardio- studies, 11% to 27% of the patients complied vascular morbidity and mortality. Diabetics with the advice to stop smoking. Within 3 years have a two- to fourfold increase in the risk of stopping, there was no reduction in limb- of CAD. Diabetics, particularly those with threatening complications of the vascular non–insulin-dependent diabetes mellitus disease. However, after 7 years, rest pain had (NIDDM) are at high risk of vascular disease developed in 16% of persistent smokers, but in because of high levels of triglycerides, LDL, and none of those who had stopped smoking. After very low-density lipoprotein (VLDL) particles. 10 years, 53% of persistent smokers suffered a Patients with NIDDM tend to produce small, myocardial infarction compared to only 11% of dense LDL particles that are more vulnerable to stopped smokers; 54% of persistent smokers oxidation. Other mechanisms for the adverse died compared to 18% of stopped smokers. In a effects of diabetes that promote vascular disease comprehensive review of the literature, absti- include glycation of arterial wall proteins, nence from smoking was found to be associated enhancement of LDL oxidation, microvascular consistently with better outcomes following disease of the vasa vasorum, change in cellular , lower amputation rates, and function,promotion of thrombogenesis,and the improved survival (Hirsch et al., 1997). development of renal disease and hypertension However, smoking cessation had probably only (Beckman et al., 2002). 3

THE EPIDEMIOLOGY AND ETIOLOGY OF ATHEROSCLEROSIS

Hypertension steroid synthesis, and formation of bile acids. The human body can produce all the cholesterol Hypertension is a well-recognized risk factor it needs. The liver is the primary producer of for atherosclerotic disease, particularly stroke endogenous cholesterol. Cholesterol is derived and to a lesser extent ischemic heart disease and from the in vivo form acetate by a mechanism peripheral vascular disease. There are several characterized by a rate-limiting step in which 3- possible mechanisms for the underlying poten- hydroxy-3-methylglutaryl coenzyme A (HMG tiation of atherogenesis by hypertension, CoA) is converted into melavalonic acid by including direct mechanical disruptive effects, HMG CoA reductase. Statin-type drugs inhibits actions on vasoactive hormones, and changes in this step. This action decreases endogenous the response characteristics of the arterial wall. cholesterol production. It is thought that, although hypertension may potentiate or enhance atherogenesis, hyperten- Lipoproteins sion alone is probably not sufficient for athero- genesis (Valentine et al., 1996). The major lipoproteins are chylomicrons, VLDL, intermediate-density lipoprotein (IDL), Homocysteine LDL, and HDL. Chylomicrons are larger triglyceride carrying Alterations in homocysteine metabolism are an particles formed after ingestion of a meal. They independent risk factor for the development of result from the processing of ingested by vascular disease. Elevations of plasma homo- intestinal mucosal cells. They are transported to cysteine levels are associated with increased the thoracic duct via the intestinal lymphatics to risks of all forms of atherosclerotic vascular eventually end up in the peripheral circulation. disease. Homocysteine can react with LDL cho- At peripheral sites the chylomicrons are acted lesterol to form oxidized LDL, which is found upon by lipoprotein lipase bound to capillary in early atherosclerotic lesions. Through this endothelium. Chylomicrons have the lowest mechanism homocysteine can promote density of any of the lipoproteins. endothelial dysfunction, lipid peroxidation, and Very low-density lipoproteins are not as large oxidation of LDL cholesterol. as chylomicrons and are slightly more dense. They carry triglycerides and other synthe- Atherogenesis and Lipid Metabolism sized in the liver. The IDLs are formed when some of the triglyceride is removed from VLDL. Central to the discussion of atherogenesis is the Under normal circumstances it is removed so metabolism of the peripheral blood lipopro- rapidly from plasma that its concentration is teins. These are a complex macromolecule of quite low. lipid and protein in which the nonpolar lipid Low-density lipoprotein is normally pro- core is surrounded by a polar monolayer of duced from the catabolism of VLDL. It is the phospholipids and heads of free cholesterol major carrier of cholesterol in the plasma. and apolipoproteins. This structure allows for It is cleared by both receptor-mediated and the transport of the relatively insoluble lipids non–receptor-mediated processes from the through the liquid plasma. The lipoproteins plasma. Low-density lipoprotein may be modi- differ in their proportions of lipid content and fied through acetylation, oxidation, or both. proteins found on their surface. Lipid disorders These modified forms are particularly impor- alter the composition and structure of the tant in the development of atherogenesis. lipoprotein. For example, as mentioned earlier, First, these molecules are cytotoxic and may patients with high triglycerides produce LDL damage the vascular endothelium, initiating with a higher protein-to-lipid ratio, yielding a atherosclerosis. They may also aggregate in the small dense LDL. intima of the vessel wall and are chemotactic for inflammatory cells such as monocytes. Cholesterol These modified LDL particles have a decreased affinity for the normal LDL receptor and thus The body uses cholesterol for numerous func- require clearance through other scavenger tions including cell membrane biogenesis, pathways. 4

VASCULAR SURGERY

Lipoprotein (a) esterified cholesterol migrates to the interior of the particle, a sphere with an outer coating of Lipoprotein (a) [Lp(a)] is a particle comparable free cholesterol and an inner core of esterified in size to LDL. It is assembled from LDL and a cholesterol and small amounts of triglyceride is large glycoprotein called apolipoprotein (a). It formed. has a decreased affinity for the LDL receptor In epidemiological studies elevated HDL compared with LDL itself. Evidence links ele- levels are associated with a reduced risk of ath- vated levels of Lp(a) with increased risk of vas- erosclerotic vascular disease. It is thought that cular disease. Lipoprotein (a) may also be taken HDL mediates this benefit through reverse cho- up by scavenger pathways and thus accumulates lesterol transport, which does not involve a in foam cells in the early atherosclerotic lesion. direct route from peripheral tissues to the liver but rather depends on repeated transfer of cho- Small-Density LDL lesterol esters among lipoproteins before excre- tion through the liver. Alterations of LDL metabolism may create species of LDL particles with higher protein- Lipid Metabolism lipid concentrations. Increased levels of these types of particles (termed small, dense LDL) are Chylomicrons are formed in the intestine from associated with increased risk of atherosclerotic ingested fat and taken by the intestinal lym- disease and with elevated triglycerides (TGs) phatics to peripheral blood and then to adipose and low levels of HDL cholesterol. The mecha- and other tissues.There,most of the triglyceride nism linking these particles and hypertriglyc- is acted upon by the enzyme lipoprotein lipase, eridemia relates to the production of transported across the cell membrane as fatty chylomicrons and VLDL that are particularly acid and monoglyceride, resynthesized into rich in TGs. Catabolism of these TG-saturated triglyceride, and stored. When necessary, intra- VLDL particles produce LDL particles that have cellular triglyceride can undergo lipolysis. The higher than normal TG content. These TG-rich released fatty acid is then transported out of the LDLs are susceptible to further lipolysis by cell and bound to albumin to be transported in hepatic lipase, producing a decrease in size and the plasma. After lipolysis a remnant of the chy- increase in the density of the particle. Small, lomicron is transported to the liver and catabo- dense LDLs are believed to be more susceptible lized as a portion of the particle apolipoprotein to oxidative modification and hence are thought A [Apo(A)] free cholesterol, and phospholipid is to be highly atherogenic. Metabolic disorders transferred to HDL formed in the liver; HDL such as diabetes and insulin resistance syn- may also pick up free cholesterol from cells. The drome often produce this lipid particle. cholesterol from other cells is esterified under the influence of LCAT. This ester is then avail- High-Density Lipoprotein able for storage or transport. Very low-density lipoprotein is synthesized in High-density lipoprotein is the lipoprotein the liver from fatty acids obtained from the pro- responsible for the transport of cholesterol from cessing of chylomicrons or from endogenously cells to other lipoprotein or catabolic sites. produced triglyceride. These particles are High-density lipoprotein may be formed de smaller and more dense than chylomicrons. The novo in the liver and intestines, and intravascu- apolipoproteins associated with VLDL are Apos larly from the redundant surface material of B-100, C-1, C-II, C-III, and E. chylomicrons and VLDL. Newly formed HDL Very low-density lipoprotein exchanges consists of free cholesterol phospholipids and triglycerides for cholesterol esters from HDL. apoproteins. Free cholesterol from cells and Like chylomicrons, lipoprotein lipase catalyzes perhaps from other lipoproteins reacts in the the hydrolysis of triglyceride in VLDL to fatty plasma with a complex containing the enzyme acids that are used by muscle or stored as fat lecithin-cholesterol acetyltransferase (LCAT), in adipose tissue. This hydrolysis step reduces apoprotein A-1, and an HDL-associated apopro- VLDL to IDL. Intermediate-density lipoprotein tein D. This complex attaches to, and the cho- can be taken up by the LDL receptor or be lesterol is esterified by, LCAT. As nonpolar reduced to LDL by hepatic lipase. Intermediate- 5

THE EPIDEMIOLOGY AND ETIOLOGY OF ATHEROSCLEROSIS density lipoprotein clearance is mediated by Apo E, which has a higher affinity for the LDL receptor than Apo BB. Low-density lipoprotein contains only the apolipoprotein B-100. Two thirds of the LDL is cleared through the LDL receptor, 60% to 70% of which is located in the liver. Peripheral cells can also take up LDL for membrane biogenesis and steroid synthesis. Low-density lipoprotein is removed from plasma by binding to these specific receptors located in many tissues,including the liver.After binding, LDL is internalized and metabolized to free cholesterol and other products. Cholesterol is stored in cells as the ester. Saturation of LDL Figure 1.1. Atherosclerotic plaque. The appearance of receptors inhibits intracellular cholesterol syn- complex atherosclerotic plaque removed during a carotid thesis by inhibiting HMG CoA reductase. This . negative feedback system operates so that intra- cellular cholesterol synthesis varies inversely with the availability of intracellular LDL. characteristic of these early lesions.It is believed that these lesions represent the precursor to Theories of Atherogenesis more advanced atherosclerotic lesions. As these lesions grow they then intrude into the arterial Numerous theories exist regarding the patho- lumen. genesis of atherosclerosis (Table 1.3). One uni- Fibrous plaques are composed of large fying hypothesis linking the various theories is numbers of smooth muscle cells and connective the “response to injury” model that in a broad tissue forming a cap over an inner core con- context embraces many aspects of the theories taining mainly lipid cholesterol esters believed (Ross, 1999). to be from disrupted foam cells. The fibrous cap may provide structural support or may function The as a barrier to sequester thrombogenic debris in the underlying plaque from the arterial lumen. Whatever the initiating process, the first lesion These plaques can show evidence of uneven and of occurs with the entry of LDL episodic growth. Intermittent ulceration and through the intima and into the arterial wall. healing may occur, and there is evidence that The lipids of human plasma are similar to what thrombi formed on lesions are incorporated can be found in these early lesions. These early into them and resurfaced with a fibrocellular lesions, termed fatty streaks, are minimally cap and an intact endothelial layer. Whether all raised yellow lesions found in the of fibrous plaques are characteristic of advanced infants and children. The lipid deposits in these atherosclerosis evolving from the lesions are found within macrophages and is uncertain. However, fibrous plaques often smooth muscle cells. Foam cells, which are appear chronologically after fatty streaks in the macrophages containing lipid particles, are same anatomical locations and characterize clinically apparent atherosclerosis. Complicated plaques comprise the end stage of atherosclerosis and cause clinical symptoms Table 1.3. Pathogenesis of atherogenesis (Fig. 1.1). These are fibrous plaques that have Response to injury become calcified, ulcerated, or necrotic. The Monoclonal hypothesis consensus, at least for coronary ischemic events, Lipid hypothesis is that they are thrombotic in origin, resulting Inflammatory from the rupture of the complicated atheroscle- Lesion regression Unstable plaque rotic lesions. In most patients myocardial infarction occurs as a result of erosion or 6

VASCULAR SURGERY uneven thinning and rupture of the fibrous cap, risk, so that eventually experts agreed on the often at the shoulders of the lesion where causal link between blood cholesterol levels and macrophages enter and accumulate. Degrada- CAD risk. tion of the fibrous cap may occur by release of As mentioned previously, the endothelial metalloproteinases, collagenases, and elastases injury hypothesis postulated the loss of by these cells. endothelial cell integrity; however, in areas of atheroma often the endothelium remains intact. Response to Injury These results suggested that monocytes pene- trate the intact endothelium,settle in the intima, The response-to-injury hypothesis initially and then take up cholesterol particles to become proposed that endothelial denudation was the foam cells. The lesion is initiated by elevated first step in atherosclerosis. More recent data blood cholesterol characterized by lipid accu- suggest that endothelial dysfunction rather mulation in foam cells. denudation is the primary problem. According This process is accelerated in vivo under con- to this model, atherogenesis is a response to ditions in which the circulating LDL is modified injury of the vascular endothelium. At its to oxidized LDL. Many biological properties of mildest, atherosclerosis may represent a repara- oxidized LDL make it more atherogenic than tive process that leads to thrombus formation native LDL including cytotoxicity. These facts and smooth muscle cell proliferation at the site are supported by data that demonstrate benefits of endothelial injury. The production of the of antioxidants in preventing oxidation of LDL endothelial injury may be from hypertension, on lesion progression. cytotoxic molecules, or blood flow changes.Ath- erosclerosis develops at sites exposed to unusual Inflammatory Theory shear stress, such as in the abdominal aortic bifurcation. Hypercholesterolemia, hyperhomo- This theory stems from the observations that cystinemia, and smoking may all contribute to atherosclerosis represents a different stage in endothelial injury. chronic inflammatory process in the artery. Unchecked, this process may eventually result in Lipid Hypothesis the advanced complicated lesion. The different forms of injury increase the Cholesterol accumulation in atherosclerotic adhesiveness of the endothelium to leukocytes lesions was initially considered an incidental and platelets. It also induces the endothelium accompaniment of the degenerative changes in to have procoagulant activities and to form the arterial wall. Forty years ago the normal vasoactive cytokines and growth factors. The range of blood cholesterol encompassed every- response then triggers the migration and prolif- one within two standard deviations from the eration of smooth muscle cells that form the mean. Cardiologists and cardiovascular sur- fibrous lesion. Macrophages and T lymphocytes geons concluded that serum cholesterol must be regulate the majority of the inflammatory com- unimportant because most myocardial infarc- ponent of this process. tions occurred in patients well below this arbi- Macrophages have the ability to produce trary normal level. The notion that the mean cytokines (such as tumor necrosis factor-a, cholesterol level in the average American was interleukin-1, and transforming growth factor- high enough to cause serious clinical illness b), proteolytic enzymes, and growth factors seemed improbable, and thus the lipid hypoth- such as platelet-derived growth factor and esis had few advocates. insulin-like growth factor. In addition, they However, the most important study to express class II histocompatibility antigens demonstrate that blood cholesterol is a risk that allow them to present antigens to T factor for CAD is the Framingham study. The lymphocytes. results of this study demonstrated the risk for developing clinically evident CAD was a contin- Plaque Regression uous curvilinear function of blood cholesterol level. Larger trials would follow substantiating Plaque regression refers to a discernible the link between cholesterol level and clinical decrease in intimal plaque. Apparent regression 7

THE EPIDEMIOLOGY AND ETIOLOGY OF ATHEROSCLEROSIS of atherosclerosis has been documented by necrotic core filled with lipid and cellular debris serial contrast arteriography in both coronary with intraplaque and intraluminal . and peripheral vascular beds. Although plaque The final feature is that of intense macrophage regression is usually thought of as a decrease in infiltration. Proteases and elastases released plaque bulk, it may proceed by other means. form inflammatory cells may contribute to the This lessening of luminal intrusion on sequen- thinning of the fibrous cap seen in these lesions. tial coincides experimentally with Additionally, they contribute to the thrombotic decreased plaque size and lipid content. nature of the unstable plaque through the elab- However, as intimal plaques enlarge, a closely oration of tissue factor. associated enlargement of the affected artery segment tends to limit the stenosing effect of the enlarging intimal plaque (Glagov et al., 1987). Prevention In the human left main coronary artery such enlargement keeps pace with increases in Hypotheses of pathogenesis and etiology of intimal plaque and is effective in preventing atherosclerosis have been tested through the lumen until plaque area occupies on manipulation of risk factors associated with this the average approximately 40% of the cross- disease process. Among the various strategies sectional area. Continued plaque enlargement tried, only those strategies that promote a or complication apparently exceeds the ability decrease in LDL or an increase in HDL have of the artery to enlarge and stenosis may then been associated with favorable changes in the develop. Thus the development of critical lumen plaque itself. stenosis, the maintenance of normal cross- Additionally, large epidemiological studies sectional area, and the development of an have demonstrated that lower cholesterol levels increase in luminal diameter are dependent on are associated with a lower overall risk of mor- the respective rates of plaque growth and arte- bidity and mortality due to CAD (Martin et al., rial enlargement. 1986). Numerous clinical trials support these epidemiological data, and show that cholesterol Unstable Plaque lowering therapies lead to a significant reduc- tion in morbidity and mortality associated with Plaque rupture is the major cause of acute CAD. Additionally, these benefits extend to a coronary syndromes (Table 1.4).Often,however, population presenting with peripheral arterial plaque rupture may be asymptomatic but con- disease as well. The benefits of statin therapy to tributes to the rapid growth of lesions as throm- decrease risk is seen as early as the first year of bus fibroses. treatment and extend not only to prevention A number of characteristics distinguish of cardiovascular disease but also to the quality stable plaque from the unstable plaque that of life. In this era of evidence-based medicine, it might produce acute symptoms. The common would be difficult not to treat patients identified underlying feature of the unstable plaque is at risk with statin therapy based on these data. thinning of the fibrous cap, which is composed Recommended treatment guidelines are given mainly of vascular smooth muscle cells and in Table 1.5. matrix. In plaques that have ruptured, the However, one must understand that the treat- fibrous cap at the shoulders of lesion where the ment to prevent or stabilize atherosclerotic cap meets the normal segment of the arterial plaques extends not just to those patients with wall is where this thinning occurs. Another demonstrable severely stenotic lesions. In fact, typical feature of the unstable plaque is a large it seems to be that most myocardial infarctions occur at sites that did not have prior angio- graphically recognized severe lesions. These Table 1.4. Characteristics of the unstable plaque facts are supported by the finding that thallium studies in stable CAD show that the site of Thinning of fibrous cap stress-induced myocardial ischemia is fre- Lipid core quently not the site of myocardial infarction. To Intraplaque thrombosis Macrophage infiltration extend this concept, it would seem reasonable to start statin therapy in patients at risk before the 8

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Table 1.5. Risk factors that modify low-density lipoprotein be extrapolated to remains to be determined. Cigarette smoking Another active debate is whether the treatment Hypertension (>140/90) or on antihypertensive for acute myocardial infarction in high-risk medication patients should be lipid-lowering therapy rather Low HDL cholesterol (<40mg/dL) than revascularization (Forrester and Shah, Family history of premature coronary artery disease in 1997). male first-degree relative or female <65 years of Additional therapeutic approaches that are age > > receiving attention include antioxidant treat- Age (men 45 or women 55 years of age) ment such as vitamin E. In a situation where Risk categories that modify LDL cholesterol goals oxidation of LDL is a major target in atheroge- nesis, antioxidant therapy obviously might play Risk category LDL goal a role. To what extent it may be of benefit is still Coronary artery disease <100mg/dL under investigation. Multiple (2+) risk factors <130mg/dL < Fundamental to the treatment of atheroscle- 0–1 risk factors 160mg/dL rosis is recognizing it as a systemic disease with the potential to affect a variety of end organs. Therefore, when patients are identified it appears advantageous to screen, counsel, and development of these unstable plaques or to treat patients as soon as possible. stabilize the ones already present. References Controversy Beckman JA, Creager MA, Libby P. (2002) JAMA 287: The importance of treating patients to lower the 2570–81. Forrester JS, Shah PK. (1997) Circulation 96:1360–2. cholesterol levels and to lessen the risk of devel- Glagov S, Weisenberg E, Zarins CK, Stankunavicius R, oping atherosclerosis is well accepted. However, Kolettis GJ. (1987) N Engl J Med 316:1371–5. the question remains whether there is a thresh- Hiatt WR, Hoag S, Hamman RF. (1995) Circulation 91: old below which cholesterol reduction may 1472–9. Hirsch AT, Treat-Jacobson D, Lando HA, Hatsukami DK. translate into clinical benefit. (1997) Vasc Med 2:243–51. On average drug therapy with simvastatin Jonason T, Bergstrom R. (1987) Acta Med Scand 221:253–60. loweres LDL cholesterol levels by 35% and Martin MJ, Hulley SB, Browner WS, Kuller LH, Wentworth reduces heart risk by 34% (Pedersen et al., D. (1986) Lancet 2:933–6. 1998). The goal of this study was to reduce total Neaton JD,Wentworth D. (1992) Arch Intern Med 152:56–64. Pedersen TR, Olsson AG, Faergeman O, et al. (1998) Circu- cholesterol below 200. However, many patients lation 97:1453–60. achieved reductions greater than this and were Ross R. (1999) N Engl J Med 340:115–26. associated with continuing but progressively Smith I, Franks PJ, Greenhalgh RM, Poulter NR, Powell JT. smaller reductions in heart attack risk. This (1996) Eur J Vasc Endovasc Surg 11:402–8. Sueta CA, Chowdhury M, Boccuzzi SJ, et al. (1999) Am J subgroup analysis estimated a 1% reduction in Cardiol 83:1303–7. LDL, reducing the risk of major coronary events Valentine RJ, Kaplan HS, Green R, Jacobsen DW, Myers SI, by 1.7%. However, at what point this benefit can Clagett GP.(1996) J Vasc Surg 23:53–61,discussion 61–3. 2 Clinical Evaluation of Patients with Vascular Disease William G. Tennant

The primary goal of the clinical evaluation of tion, and rupture. Many elderly patients with vascular disease is to decide which patients suffer other severe illness or disability. tests will help the surgeon treat the patients’ They may, as a result, have limited aims and problem while at the same time minimizing aspirations when seeking investigation and patient discomfort. Investigation of patients treatment. In contrast, younger patients’ family with vascular disease differs from that of other life or career may be threatened by their disease, surgical patients and depends mainly on the and very high expectations of investigation and underlying disease process. For instance, treatment have to be realistically modified. It is patients with lower extremity occlusive vascular these human characteristics that deserve our disease suffer not only from their index problem consideration when deciding on an investigative (claudication, ischemic rest pain, gangrenous pathway. Although it is important to gain all the ulcers) but also from some of the conditions that information required to execute an effective have predisposed them to vascular disease in the treatment plan, it is equally important to do this first place (diabetes, hypercholesterolemia, etc.). in as noninvasive and humane a way as possi- In addition, they are likely to require a number ble. Fortunately, the technology is on our side in of medications for these predisposing condi- this regard, and the days of highly invasive tions, some of which require consideration in investigations are probably numbered. diagnosing and treating vascular disease. It is also important to keep in mind that the presence of occlusive vascular disease in the lower limbs The History indicates the likely involvement of other vessels (coronary, carotid, cerebral, renal, mesenteric, The value of a good clinical history is increas- etc.). Because the underlying pathology is very ingly overlooked as techno-diagnosis advances. different, the clinical evaluation of patients with One should remember that the history is usually aneurysmal disease is strikingly different. These the first interaction that takes place between the patients are healthier overall and their clinical doctor and patient. It is at this time that the evaluation is less intense. therapeutic relationship is forged.With skill and practice it is possible to elicit not only symp- toms but also their significance to the patients, Patients’ Characteristics the patients’ expectations and fears, and their attitudes toward treatment. It is possible to Vascular surgery patients suffer many of the avoid unnecessary diagnostic tests and limit fears and anxieties of other surgical patients. the investigative mill that the patient is put Added to this are fears of gangrene, amputa- through.

9 10

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There are some general points in the clinical pain relieved by rest. In the lower limb, patients history that warrant mention: in the initial stages of disease complain of calf, thigh, or buttock pain brought on by walking, 1. Lifestyle. Risk factors that can lead to which is relieved after a few minutes of rest. the progress of vascular disease such as This is commonly a condition that follows a smoking, diabetes, hypertension, and variable course with periods of remission and hyperlipidemia are ascertained in the relapse, often according to changes in lifestyle, history. Additionally, an adequate exercise medications, or the progress of a comorbid con- history should be elicited. One question dition such as diabetes mellitus. With worsen- that elucidates the rate-limiting organ ing ischemia, the patient begins to feel pain system is how far patients can walk, and at night usually in the distal forefoot, toes, what stops them (leg pain, shortness of and instep (rest pain). As the patient becomes breath, chest pain, etc.). It is also important horizontal in bed (removing the effect of gravity to know if the patient is taking hormonal on blood flow), and the drops medications such as oral contraceptives with the onset of sleep, perfusion of the lower or hormone replacement therapy. These limbs worsens. Patients often wake up in the medications can predispose to venous middle of the night with pain that they can and occasionally arterial thrombosis. It is relieve only by getting out of bed and, paradox- during the history taking that a physician ically, walking around the bedroom. Some can begin to address many of these risk patients with rest pain learn to sleep with the factors. By recruiting antismoking clinics affected leg hanging over the side of the bed to or eliciting the help of diabetes and cardiac regain the assistance of gravity (Fig. 2.1). When specialist physicians, a surgeon can patients sleep with ischemic limbs dependent, improve a patient’s overall health both pre- there is a gradual onset of edema and worsen- and postoperatively. ing tissue perfusion, which create a vicious 2. Family history. It is especially important to circle of pathologies. question the patient about the prevalence of early cardiovascular disease or throm- bosis (i.e., stroke, occlusive limb disease, or Acute Critical Limb Ischemia cardiac disease) that manifests before age 50. Aneurysm disease has a clear familial Acute critical limb ischemia (ACLI) can be association, and an incidence approaching defined as sudden onset of severe limb 20% in first-degree relatives. ischaemia of less than 24 hours’ duration. The 3. Atherosclerosis. Atherosclerosis is a sys- principal causes are arterial and temic disorder, so inclusion of a discussion thrombosis. A history should be taken to of stroke/transient ischemic attacks and include the common sources of emboli (Table coronary artery disease/myocardial infarc- 2.1). A history suggestive of claudication in tion/angina is important. the affected limb makes thrombosis in situ of a chronic arterial stenosis more likely than Although the points covered above may elicit embolus. factors predisposing the patient to vascular The symptoms of ACLI include paresthesia, occlusive or aneurysm disease, they are non- pain in the limb at rest, numbness, coldness, and specific and nondiagnostic. Because the symp- paralysis. Symptoms are likely to be more severe toms of occlusive vascular, aneurysmal, and in cases of embolus than in cases of thrombosis venous disease differ,they will be dealt with sep- because thrombosis usually occurs at the site of arately below. It should be remembered, a chronic stenosis, completely occluding the however, that they may occur in combination. vessel. Where a stenosis has existed, it is likely that a collateral circulation has developed that Chronic Limb Ischemia will continue to function even when the main vessel is occluded. In cases where an embolus The principal symptom of chronic limb has suddenly occluded a previously normal ischemia (CLI) is that of claudication (claudi- limb artery, there are no collaterals to support care, to limp). This is effort-related muscular adequate perfusion. 11

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

Perhaps because of its rarity, the diagnosis is often made late and by exclusion. Arm claudi- cation presents with effort-induced heaviness or tiredness that is relieved by rest. The patient may also complain of relative pallor and an impression of coldness of the affected limb, exacerbated by cold exposure. Subclavian occlusive disease may also cause cerebrovascular symptoms because of the anatomical relationship between the vertebral that arise off of the subclavian arteries. This is best exemplified by the subclavian steal syndrome. Tight stenosis or occlusion of the subclavian artery proximal to the origin of the vertebral artery leads to effort-induced reversal of flow in the vertebral artery that contributes to the arterial supply of the arm (Fig. 2.2).When the arm is exercised, increased (reversed) flow from the vertebral artery to the subclavian can lead to marked but transient symptoms of brainstem ischemia in addition to arm claudi- cation. Although most patients with this condi- tion have no symptoms of cerebrovascular steal at rest, symptoms can occur during exercise, including dizziness, ataxia, diplopia, and bilat- eral blurred vision. Acute upper limb vascular disease is usually due to embolism. Trauma is a less common Figure 2.1. Rest pain.This elderly woman is adopting a classic posture, which gives gravity assistance to blood flow while she is recumbent.

Upper Limb Vascular Circle of Willis Occlusive Disease Chronic occlusive vascular disease in the arm is considerably less common than that in the leg.

Internal Vertebral Table 2.1. Common sources of emboli carotid artery artery Cardiac arrhythmias (commonly atrial fibrillation) Cardiac mural thrombus from recent myocardial infarction Diseased heart valves Atheroma of aortic arch or more distal aorta Areas of chronic arterial damage (cervical rib, thoracic outlet syndrome) Severe stenosis (rare) or occlusion Broken catheter tips of proximal Bullets and other materials introduced violently subclavian artery Air Amniotic fluid Fat (long bone fractures) Figure 2.2. Subclavian stenosis can lead to reversal of flow in the vertebral artery and vertebrobasilar symptoms. 12

VASCULAR SURGERY cause. The symptoms are the same as for acute unknown, are principally severe abdominal and lower limb disease: pain or numbness, paralysis, back pain of sudden onset. The pain may radiate and pallor. A history of recent myocardial into the groin, flanks, or genitalia and can infarction or of known atrial fibrillation should closely mimic renal colic.When the aneurysm is be taken. Traumatic causes can range from a ruptured, there is also collapse and hypov- “simple” supracondylar humeral fracture to the olemia. The distinction between acutely symp- massive bone and soft tissue disruption caused tomatic intact and ruptured by motorcycle accidents. It is also important to aneurysms is impossible to make on history find out how the symptoms have developed over alone. time. For instance, many elderly patients with brachial emboli give a history of severe pain ini- tially followed by gradual resolution over the Superficial Venous Disease succeeding hours. These patients then present Patients frequently complain about the to the vascular surgeon with viable limbs and unsightly nature of , and imbue minor symptoms. Other patients may complain them with many symptoms. These include of worsening symptoms, and the need for aching, itching, and swelling. Symptoms, urgent intervention becomes obvious.Where an however, correlate poorly with the apparent artery has been damaged by trauma, there may severity of the disease. When superficial venous be a clear history of resolution of symptoms disease is extensive and severe, symptoms are and restoration of pulses after, for instance, the common and include those above with the addi- reduction of a fracture. tion of ulceration. Aortic Aneurysm Deep Venous Disease Whether the aneurysm affects the thoracic or abdominal aorta, there are usually very few Symptoms are usually of swelling, heaviness, symptoms. Chronic symptoms that do occur are and occasionally severe discomfort. The symp- usually due to pressure effects on the surround- toms are usually worse after prolonged stand- ing structures. Even in quite small abdominal ing. There may be a history of deep venous aneurysms, erosion of adjacent vertebral bodies thrombosis or previous abdominal or pelvic can occur, leading to back pain. One of the com- surgery with venous damage. Symptoms result monest symptoms of large thoracic aneurysms from venous hypertension in the limb affected, is dysphagia from direct pressure on the esoph- and this is the final common pathway of both agus. Patients who notice abnormal abdominal occlusion and incompetence of the deep veins. pulsation (frequently while bathing, or in bed) There may be a history of ulceration even if often present with amusing self-diagnoses that none is present at the time of examination. belie the serious nature of the condition. This has been called “slipped-heart syndrome.” In the special case of inflammatory abdomi- Clinical Examination nal aortic aneurysm (vide infra), fibrosis can extend laterally in the retroperitoneum to Inspection include the ureters, which can result in ureteral stenosis. The presentation of such aneurysms The general signs of a predisposition to occlu- is often via the urologist, the patient having sive vascular disease include deposits of fat in presented with symptoms due to obstructive the thin skin around the eyes (xanthelasma), uropathy and hydronephrosis or even renal and in the corneas themselves (arcus senilis). failure. Patients may have white hair; the fingertips may The acute presentation of abdominal aortic be tinted yellow with tar from cigarettes, and aneurysm is usually as a differential diagnosis patients may smell strongly of cigarette smoke. of acute abdominal pain. Symptoms are not Some of these patients assert that they have always due to rupture, and the aneurysm may stopped smoking. Patients may be short of be intact but acutely symptomatic. Symptoms in breath at rest or on minimal exertion because of an intact aneurysm, though the etiology is coexistent cardiac or respiratory disease. 13

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

The specific effects of occlusive vascular disease may produce clinical signs apparent on general examination, such as limb swelling ulceration or gangrene. There may be signs of a previous stroke or of severe loss of weight. Aneurysms may appear as a localized swelling if present in the periphery, for instance, traumatic aneurysms of the femoral, popliteal, or radial artery (Fig. 2.3). There are often very few signs of abdominal aortic aneurysms on general examination, unless the patient is very slim and the abdominal wall may be “draped” across the aneurysm with the patient supine and relaxed. The pressure caused by an aneurysm on adjacent structures may rarely cause related clinical signs (Fig. 2.4). Palpation: Examination of the Pulses Lower Limbs Pulses are normally palpable in the femoral tri- angle at the midinguinal point, in the popliteal fossa, posterior to the medial malleolus, and on the dorsum of the foot between the first and second metatarsals. In the normal subject, the popliteal pulse is felt by compressing the artery against the tibial plateau anteriorly. This is best Figure 2.4. Swelling due to venous congestion from a popliteal done with the patient’s leg flexed at the knee. aneurysm. A popliteal aneurysm caused the swelling of this It is particularly important to distinguish aor- patient’s left leg by pressure on the adjacent popliteal . toiliac disease from infrainguinal disease. In There are also multiple small skin infarcts caused by emboliza- tion from the aneurysm. aortoiliac disease the femoral pulses are dimin- ished, whereas in infrainguinal disease the femoral pulses are normal. Upper Limbs The subclavian pulse is present in the supra- clavicular fossa and the axillary artery in the infraclavicular fossa. Thereafter, the brachial artery is usually palpable in the cubital fossa deep to the bicipital aponeurosis. The ulnar pulse is palpable just medial to the tendon of the flexor carpi ulnaris and the radial lateral to the tendon of the flexor carpi radialis on the radial styloid process. A pulse is usually also palpable in the “anatomical snuff box” between the tendons of the extensor pollicis longus and brevis, where it overlies the scaphoid bone.

Neck Figure 2.3. This aneurysm of the superficial femoral artery was caused by previous trauma. It presented as a pulsatile swelling The carotid pulse can be felt medial to the of the mid thigh. muscle belly of sternomastoid. Occasionally 14

VASCULAR SURGERY there may be marked tortuosity of the carotid artery in the neck, giving the impression of an aneurysm.

Abdomen It is usually difficult to feel the normal abdom- inal aorta without causing the patient discom- fort. The aorta is best palpated between the xiphoid and umbilicus. Below the umbilicus, the aorta bifurcates.When aneurysmally dilated the pulse is easier to feel, and may in fact be a presenting symptom.

Auscultation Figure 2.5. Pallor on elevation.The patient’s leg is elevated,and the foot displays profound pallor. In each case, palpation of the pulses should be followed by auscultation in the same sites. Where there is a stenosis either at or immedi- of diagnosis and management (Sumpio et al., ately proximal to the point of examination, a 2003). bruit will be heard in time with the cardiac systole. This is particularly relevant in carotid stenosis. Carotid bruits are not very sensitive Other Clinical Tests or specific for carotid stenosis and require Capillary Refill confirmation by carotid ultrasound (Magyar et al., 2002). However, a carotid bruit is often With the patient supine and the great toes indicative of systemic atherosclerosis. Rarely, together, both toes are gripped by the examiner the bruit of a stenosed renal artery can be heard using one hand and compressed. On release, the during auscultation of the . toes should change symmetrically from white to pink in less than 5 seconds.Asymmetry suggests Differential Diagnosis of Leg Ulcers arterial disease on the slowest side. Many vascular patients present with ulcera- Buerger’s Test tions. There are three major types of leg ulcers: venous, ischemic, and neuropathic (Table 2.2). This is a test for severe chronic arterial occlu- Ischemic ulcers tend to be very distal in the vas- sive disease.With the patient supine the straight cular tree and painful. Venous stasis ulcers tend legs are raised as far as possible. In arterial to occur in the region of the medial malleolus disease, there is extreme pallor of the feet in this and have associated brownish discoloration of position (Fig. 2.5). The legs are then placed on the skin (lipatodermatosclerosis) and edema. the examination bench and the patient is told to Neuropathic ulcers tend to occur in diabetic sit with the legs dependent over the side of the patients under pressure points. Patients with bench. Where there is severe chronic arterial diabetes present particular challenges in terms disease, the feet become suffused with a deep ruddy red color, commonly described as “sunset Table 2.2. Differential diagnosis of leg ulcers foot.” This is caused by ischemic maximal dila- tion of the arteriolar bed of the skin, allowing Type of Location Pain Associated the skin to fill with partially oxygenated blood ulcer findings (Fig. 2.6). Ischemic Distal foot Yes No pulses Venous stasis Medial Maybe Stasis malleolus dermatitis Trendelenburg Test Neurotropic Pressure No Diabetes points In cases where incompetence of the saphe- nofemoral junction is suspected as a major 15

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

frequencies between 5 and 10MHz depending on the depth of penetration required (Fig. 2.7). In each case the signal from the insonation of the examined artery is converted into an audible sound from a built-in speaker. Normally the signal has a “triphasic” sound. Although it is possible to use the Doppler simply to locate an artery, the most common use is to measure the blood pressure at the periphery of a limb. For this, the Doppler machine is used in the same way as a stethoscope when measuring the blood pressure using Korotkoff sounds. A blood pres- sure cuff is placed around the limb proximal to the artery to be examined. The artery is then Figure 2.6. Dependent rubor.The leg has been placed depend- insonated and the cuff inflated above the sys- ent over the side of the bed, and is extremely hyperemic. tolic pressure. As the cuff is deflated, the signal returns, and the pressure at which this happens is noted. When the pressure in all the required arteries has been measured, the pressure in the cause of superficial varicose veins, the patient is brachial artery is measured using the same tech- asked to lie supine and raise the affected limb to nique. The ratio between the ankle pressure about 45 degrees. Venous blood is “milked” and the brachial pressure is known as the proximally by firm stroking of the leg to empty ankle–brachial index (ABI). The ABI in normal all of the superficial veins. A tourniquet is patients without arterial occlusive disease is applied as proximally as possible to occlude the greater than 1. superficial venous system. The patient is then Handheld Doppler examination is also useful asked first to sit up and swing the legs over the in the diagnosis of superficial venous disease side of the examination couch, and then to stand. Where saphenofemoral incompetence is the major cause of superficial varicosities, the varicosities will remain collapsed. It is usual for the superficial veins to fill slowly, but rapid filling of the varicosities with the tourniquet in place indicates significant perforator disease distal to the tourniquet. It is possible to localize incompetent perforating veins by repeating the test with the tourniquet just above the knee. In this case calf varicosities will remain collapsed if the guilty perforating vein is between the saphenofemoral junction and the tourniquet. If the incompetent perforating vein is below the knee, the below knee varices will fill rapidly. Although the Trendelenburg method is some- what insensitive in localizing incompetent per- forating veins, it can provide useful clinical information. For more accurate localization of incompetent thigh perforators, and for all those in the calf, it is best to use duplex examination.

Fixed Wave Doppler Examination A number of small and portable battery- Figure 2.7. An example of the type of handheld Doppler device operated machines are available, operating at suitable for use in the clinic. 16

VASCULAR SURGERY to confirm the incompetence of the saphe- blotches blanche on finger pressure (unfixed nofemoral or saphenopopliteal junctions, and to mottling), it may still be possible to save the leg localize incompetent perforating veins. At each if immediate action is taken to revascularize it. of the saphenous junctions, there is physiologi- Where the mottling is fixed, that is, it fails to cal retrograde flow into the superficial system of blanche on pressure, it is too late to save the under 1 second’ duration, which is audible using limb. Muscle ischemia and impending necrosis a handheld Doppler machine. If the reflux is of in these severe cases cause the muscles to swell longer duration, it is indicative of pathological and become tender. This is often best seen in the incompetence of the junction. With an experi- anterior muscle compartment where the ten- enced operator, it is possible to localize incom- derness is often exquisite and the compartment petent perforating veins. is almost stone hard to palpation. Examination of the pulses allows approximate localization of the level of disease. The presence of normal Clinical Examination pulses on the opposite extremity supports the of Specific Conditions diagnosis of acute embolic disease. Chronic Lower Limb Ischemia Mesenteric Ischemia In mild disease the legs may appear normal to In chronic cases there are often few signs on inspection, but capillary return is delayed and examination of the abdomen, but signs of the feet may be cool to touch. Distal pulses are weight loss and systemic vascular disease be either weak and difficult to feel or absent. are present. Where the disease is acute, the With increasing severity, the legs may be hair- abdomen can feel curiously doughy in the early less below the knee, and the toes cyanotic. As stage and is diffusely tender. Bowel sounds may ischemia progresses, more proximal pulses may still be present. As time passes and transmural disappear and ulcers may appear on or between infarction supervenes, peritoneal signs develop. the toes. Buerger’s test becomes positive. Even- tually more proximal painful ulcers over the lower leg, and digital gangrene signals very Upper Limb Ischemia severe occlusive disease. Chronic arterial occlusive disease seldom affects the upper limb except as part of rare conditions Acute Lower Limb Ischemia affecting the aortic arch and subclavian ar- teries. Upper limb ischemia is usually due to Where there is thrombosis of a collateralized embolism. The commonest embolic source in chronic stenosis, the signs of acute ischemia these cases is the myocardium in atrial fibrilla- may be less severe than in cases of embolus tion or following myocardial infarction. Other (vide supra). In these less severe cases, the acute sources include proximal stenoses in the aortic onset of the symptoms may be the most obvious arch and subclavian arteries (Fig. 2.8). The clin- clue. The limb may appear normal to inspection ical signs of acute upper limb ischemia are the but have reduced capillary return, pale rapidly same as in the lower limb: sensory alteration, on elevation, and have slightly altered sensation paresthesia,weakness,and muscle tenderness.It on formal testing. There may be some weakness, is uncommon for the ischemia to be so severe as principally of the anterior muscle groups of the to lead to irreversible change because of the rich lower leg. With increasing ischemia, the signs collateral supply in the arm. In intravenous drug of pallor and weakness increase, and there may abusers, intraarterial injection of illicit medica- be complete paralysis of the foot and toe tions “cut” with insoluble excipients may lead to dorsiflexor muscle groups. In these cases, the extensive acute occlusion of small distal vessels foot usually lies at rest in equinovarus due to (Fig. 2.9). Patients often present following delib- paralysis of the peroneal muscles. In severe erate or accidental intraarterial injection, with acute ischemia, such as that caused by a short history of almost overwhelming pain embolism, the skin becomes mottled with blue together with exquisite muscle tenderness and blotches on a background of sallow white. If the forearm muscles stone hard to touch. The skin 17

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

of the forearm and hand is fixed and mottled and the hand clawed. Chronic Venous Disease Inspection with the patient standing is one of the most important aspects of the examination of chronic venous disease. The dilated veins of superficial disease are frequently obvious. Other signs of importance include swelling, hemo- siderosis of the skin of the malleolar area, lipodermatosclerosis, atrophie blanche, and ulceration (Fig. 2.10). Deep venous disease may be less obvious and present simply with chronic Figure 2.8. Gangrene from an arterial embolus. The distal swelling of the limb. In later stages, all of the aspect of the digit is gangrenous secondary to an embolus above signs may be present. arising from a subclavian stenosis.

Figure 2.9. Gangrene from drug injection. Injection into Figure 2.10. Chronic venous insufficiency. The limbs demon- the radial artery led to gangrene to the thumb and thenar strate the brownish discoloration associated with lipatoder- eminence. matosclerosis.Varicosities are also present. 18

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Conclusion shed light on the clinical extent of a patient’s disease process. Finally, when radiological Clinical evaluation of the patient with vascular studies may take valuable time, there are several disease is of the utmost importance. Many clues bedside tests that can be performed rapidly, about a patient’s temperament, the disease, and allowing a vascular surgeon to make immediate expectations of treatment can be obtained from treatment decisions. a thorough interview. Assessing a patient’s risk factors for vascular disease not only helps the physician better understand the patient’s chief References complaint but also directs the preoperative Magyar MT, Nam EM, Csiba L, Ritter MA, Ringelstein EB, workup of the patient. Despite the recent Droste DW. (2002) Neurol Res 24:705–8. advances in vascular radiology, nothing replaces Sumpio BE, Lee T, Blume PA. (2003) Clin Podiatr Med Surg an excellent physical examination, which can 20:689–708. 3 Noninvasive Vascular Examination Colleen M. Brophy

The noninvasive vascular laboratory assists to place the probe directly over the artery but at with the diagnosis of peripheral arterial disease. a 45- to 60-degree angle to obtain the best In general, two basic approaches are used: (1) signal. Doppler signals can be used to assess the indirect measures that characterize the func- severity of the disease. A blood pressure cuff tional severity of the disease, such as segmental is inflated just above the ankle and a Doppler pressures, Doppler waveform analyses, plethys- signal is listened for while the cuff is deflated. mography,and skin perfusion pressures; and (2) The highest pressure in which a signal is heard direct measures that characterize the anatomy (dorsalis pedis compared to posterior tibial) is of the disease using color duplex imaging. These the ankle index.A similar approach with a blood studies are used to accurately diagnose the loca- pressure cuff on the upper arm and a Doppler tion and extent of peripheral arterial disease, probe on the brachial artery is used to deter- assist with the planning of therapeutic options mine the brachial index. The ratio of the for the disease, and follow the outcomes of ankle to the brachial index represents the peripheral vascular interventions. ankle–brachial index (ABI). The ABI is usually 1 or greater. An ABI of 0.5 to 0.8 is consistent with claudication, and less than 0.4 is consistent Indirect Evaluation of with critical limb ischemia. Diabetic patients Arterial Disease often develop medial calcinosis. Simply stated, the medial wall of the vessels become calcified Ankle-Brachial Index (“bone-like”) and cannot be compressed by a blood pressure cuff. Thus, the ABI in a diabetic In patients without palpable pedal pulses, the patient may be falsely elevated, and other next step in the clinical evaluation is to perform studies are needed to accurately assess the a Doppler analysis. This is usually performed in peripheral vascular status. In general, however, the clinic or at the bedside using a handheld the ABI is a useful screening test for peripheral Doppler device. The probe is placed at an angle vascular disease. (Fig. 3.1) over the dorsalis pedis and posterior tibial arteries to determine if a signal can be Segmental Limb Pressures obtained. The complete absence of Doppler signals suggests significant peripheral arterial Segmental limb pressures assist with determin- disease. Approximately 10% of the normal pop- ing the location of disease by measuring the ulation does not have a dorsalis pedis artery; pressure in the upper thigh, lower thigh, below hence, the absence of a dorsalis pedis signal the knee, just above the ankle, and at the trans- alone is not a significant finding. It is important metatarsal level (Figs. 3.2 and 3.3). Again using

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disease. It is important to make a distinction between aortoiliac and infrainguinal disease because the overall approach is somewhat different. An additional useful measurement, particu- larly in diabetic patients, is to measure the digital pressures. The digital arteries are less likely to be affected by medial calcification and hence provide useful information when the ABI is falsely elevated. Digital pressures are meas- ured by placing a pneumatic cuff around the digit and measuring a plethysmographic arte- rial waveform using a photoelectrode on the end of the digit. In general, a normal toe pres- sure is 80% to 90% of the brachial pressure (normal toe–brachial index is 0.8 to 0.9). A less than 38mmHg has been correlated Figure 3.1. Doppler signals are best obtained by holding the with impaired forefoot wound healing (Vitti Doppler probe at an angle over the artery that is being et al., 1994). insonated. In patients with symptoms consistent with claudication but relatively normal indices, exer- cise testing should be performed. A standard a Doppler, an arterial signal is found at the dor- exercise test involves measuring the ABI at rest salis pedis or posterior tibial artery, the cuff followed by walking on a treadmill at 2 miles/ is inflated until no signal is heard, and then hour at a 10% to 15% incline for 5 minutes. deflated until the signal resumes. The systolic The ABI is recorded 1 minute after exercise. pressure is recorded for each cuff at each loca- Normally, after exercise, there is a slight in- tion. A gradient (decrease) in pressure greater crease or no difference in the ABI. If the ABI than 20mmHg between adjacent levels suggests decreases after exercise, this is consistent with arterial occlusive disease in the vessel between claudication. the two cuffs (Fig. 3.3). An arterial pressure in the thigh that is less than that in the arm sug- Pulse Volume Recording gests aortoiliac occlusive disease. A drop in pressure between the upper thigh and lower Pulse volume recordings (PVRs) are a plethys- thigh cuffs suggests superficial femoral artery mographic measure of limb perfusion.

Figure 3.2. Segmental limb pressures are measured by placing the cuffs along the extremity. 21

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Plethysmography is essentially a measurement of volume. In general, the same cuffs are used to obtain segmental limb pressures and PVRs. The cuff is inflated and the volume shift that occurs with the cardiac cycle in that limb segment is recorded as a waveform. The PVRs do not provide quantitative data but can be analyzed in a qualitative manner. In normal patients there is a brisk upstroke, rapid decline, and dicrotic notch in the waveform. In the presence of peripheral arterial disease, the waveform becomes broader with a decreased amplitude. A PVR tracing that is flat at the forefoot (trans- metatarsal) level is consistent with significant peripheral vascular diseases and suggests that revascularization will be required for any fore- foot lesion to heal. Doppler Waveform Analysis Similar to PVRs, the Doppler waveform can be analyzed to determine if there is disease.Instead of an audio signal, a digital signal is converted to a tracing. Normally the waveform is triphasic (Fig. 3.4). With moderate disease the reverse flow component is lost and the waveform is monophasic. With severe disease, the waveform is blunted and/or absent. Skin Perfusion Pressure The skin perfusion pressure (SPP) is an addi- tional noninvasive vascular evaluation that is useful to determine which foot ulcers will heal with local wound care or minor amputation and which will require revascularization or major amputation. An SPP of less than 30mmHg can predict failure of forefoot wound healing with

Figure 3.3. Segmental limb pressures show a low high-thigh pressure, indicating iliac disease, and a drop-off between the high-thigh and low-thigh pressures, indicating superficial femoral artery disease on the left side.On the right side there is a drop-off between the pressures in the low thigh and popliteal, indicating distal superficial femoral artery/popliteal artery disease. ABI, ankle–brachial index; Dorsaus Pedis (DP), Posterior Tibial (PT), prothrombin time; PVR, pulse volume recording.

Figure 3.4. Normal triphasic Doppler waveform. 22

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Table 3.1. Noninvasive measurements consistent with impaired wound healing Ankle–brachial index (ABI) <0.3–0.4 Toe pressure <35–40mmHg Skin perfusion pressure <30mmHg Pulse volume recording (PVR) Flat forefoot tracing

an accuracy of 80% (Castronuovo et al., 1997). Skin perfusion pressure has largely replaced transcutaneous oximetry. What Wounds Will Heal? Figure 3.5. Color duplex image of a high-grade carotid The aggregate measurements that are consistent stenosis with a peak systolic velocity of 319 and end-diastolic with impaired wound healing are listed in velocity of 123. Table 3.1. However, it is ultimately the clinical response to wound care that is the most impor- tant factor.If debridement and wound care leads abnormalities occur in the first 2 years after to consistently unhealthy appearing wounds, implantation, graft surveillance is most impor- angiography and revascularization should be tant in this time frame. A PSV greater than 150 considered. If good wound care leads to healthy to 200cm/second is considered abnormal. In granulation tissue, further evaluation is likely addition, the ratio of the velocity at the stenosis unnecessary. to the normal proximal velocity is used to determine the degree of stenosis (Vr). In addi- tion, high EDVs (>100cm/second) are also sug- Direct Evaluation of gestive of high-grade stenoses. Although the high-velocity criteria (PSV, EDV, Vr) are the Arterial Disease most accurate to assess the risk of graft throm- bosis, low-velocity criteria are also helpful. The Color duplex imaging or “duplex” imaging graft flow velocity (GFV) should normally incorporates real-time B-mode imaging and exceed 45cm/second. The velocities are used to pulsed Doppler spectral analysis (Fig. 3.5). B- stratify the risk of thrombosis (Table 3.3) (Mills, mode imaging directly views the blood vessel 2001). Prophylactic graft revision should and provides anatomical detail of the vessel. be considered in grafts with a high risk of This modality can analyze plaque characteris- thrombosis. tics, identify thrombus and the intimal flaps, Duplex examination is also useful for the and measure vessel diameter (to detect diagnosis of popliteal artery aneurysm. This aneurysms and ). condition should be suspected if a widened B-mode imaging is also used to localize areas popliteal pulse is palpated. An arterial diameter of stenosis so that Doppler velocities can be determined. Velocity analyses are an indirect measure of the degree of stenosis. For carotid artery analyses, the degree of stenosis is esti- Table 3.2. Doppler velocity criteria for carotid stenosis mated based on the peak systolic velocity (PSV), Stenosis (%) PSV EDV (cm/sec) Vr end-diastolic velocity (EDV), and the ratio of Normal <123 <140 <4.0 the PSV at the stenosis to the velocity in the 1–15 <123 <140 <4.0 < < < common carotid artery (V ). In general a V 16–49 123 140 4.0 r r 50–79 >123 <140 <4.0 greater than 4 is indicative of clinically 80–99 >123 >140 >4.0 significant stenosis (Table 3.2).

Infrainguinal graft surveillance can be per- EDV, end-diastolic velocity; PSV, peak systolic velocity; Vr, velocity formed with duplex imaging. Because most ratio. 23

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Table 3.3. Risk stratification for graft thrombosis Conclusion Category PSV Vr EDV GFV (cm/sec) (cm/sec) (cm/sec) Noninvasive vascular laboratory tests comple- Highest risk >300 >3.5 >100 <45 ment the clinical evaluation in determining High risk >300 >3.5 <100 >45 the appropriate therapeutic approaches to Intermediate 180–300 >2.0 <100 >45 patients with peripheral vascular disease. The risk specific laboratory tests should be tailored to Low risk <180 <2.0 <100 >45 the individual patient’s diagnoses. The labora- EDV,end-diastolic velocity;GFV,graft flow velocity;PSV,peak systolic tory provides noninvasive information on both

velocity;Vr, velocity ratio. functional and anatomical aspects of vascular disease. greater than 10mm is considered abnormal. Bilateral aneurysms are seen in about 50% of References cases,and proximal aneurysms occur in approx- imately 30% to 50% of patients. Consequently, it Castronuovo JJ Jr, Adera HM, Smiell JM, Price RM. (1997) J Vasc Surg 26:629–37. is imperative that aneurysms at other locations Mills JL Sr. (2001) Semin Vasc Surg 14:169–76. be excluded, with abdominal aortic aneurysms Vitti MJ, Robinson DV, Hauer-Jensen M, et al. (1994) Ann and femoral aneurysms the most common. Vasc Surg 8:99–106. 4 Radiological Investigations Steven M. Thomas, Kong T. Tan, and Mark F. Fillinger

This chapter offers an overview of the available • When considering endovascular treatment imaging techniques used in vascular radiological of , the current lim- practice for the investigation of vascular diseases itations of noninvasive testing mean that and how they can be used for a range of common catheter arch angiography is required to vascular conditions.This discussion emphasizes assess the arch vessels and the whole of the the move away from invasive techniques and carotid artery. toward noninvasive techniques for the diagnosis • Computed tomography (CT) pulmonary of vascular diseases. We then describe the range angiography has resulted in little need of endovascular techniques currently required for conventional pulmonary angiography for the investigation and treatment of vascular in the diagnosis of pulmonary embolic disease. The most important contemporary disease. approaches and therapies are described,showing • Arterial closure devices enhance patient the important role these techniques now play in throughput, and this may offset the the management of a range of vascular disease increase in cost from their use. However, processes.This discussion demonstrates how the they can produce serious complications. area of endovascular intervention remains at the forefront of developments in minimally invasive • There is little evidence that primary - techniques to treat vascular disease.Approaches ing is superior to primary for specific manifestations of peripheral vascular alone in the treatment of arterial occlusive disease are not discussed, but the Trans Atlantic disease in the peripheral circulation. Inter-Society Consensus (TASC) document is • Following endovascular aneurysm repair recommended as an overview of endovascular (EVAR) for abdominal aortic aneurysms intervention in the management of specific as- (AAAs), long-term costs of stent-graft pects of peripheral arterial disease (Dormandy surveillance,and secondary treatment,may and Rutherford,2000). outweigh the short-term benefits of EVAR. Controversies Radiological Investigations and Endovascular Approaches The following controversies currently exist in the field of vascular radiology: The first vascular imaging technique was • Conventional diagnostic catheter angiog- described at the end of the 19th century shortly raphy is likely to be made obsolete by non- after the discovery of the x-ray. This technique, invasive vascular imaging. described by Haschek and Lindenthal, involved

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VASCULAR SURGERY the injection of a chalk-based contrast agent devices broadened the range of conditions into the vein of an amputated hand. In vivo amenable to treatment using interventional vascular imaging was first described in the vascular radiological techniques. 1920s using agents such as lipiodol, strontium Improvements in the design of catheters and bromide, sodium iodide, and Selectan. The other devices have resulted in smaller caliber contrast agents were usually introduced by a catheters and introduction sheaths. These along catheter, following exposure of the vessel used with the introduction of closure devices to seal for catheterization, or by percutaneous needle the access site puncture allowed the develop- puncture to directly inject contrast into the ment of day case (“same day”) arterial proce- vessel. Translumbar used this type dures for both diagnosis and intervention. of technique as early as the 1930s. However, it Despite these improvements, developments in was developments from the mid–20th century other noninvasive imaging modalities meant that brought angiography and subsequently that for arterial imaging and diagnosis, the use vascular intervention to the forefront in vascu- of what remains an invasive technique is lar diagnosis and treatment. The first of these required less frequently. Whereas arteriography was the introduction of the was once a first-line investigation, noninvasive in the 1950s that allowed safe percutaneous techniques such as ultrasound, radionuclide access to vascular structures. There then fol- imaging, CT, and magnetic resonance imaging lowed significant improvements in the range of (MRI) now have a much wider role to play in available catheters to aid in gaining access to the both general diagnostic radiology and in the different vascular beds, and rapid film changers radiological investigation of vascular disease. allowed high-quality images to be obtained of Not only are these techniques safer, they also all the major vascular beds. As a result, vascular have the potential for a greater diagnostic yield imaging became a major branch of diagnostic because of the additional information that can medicine. However, arteriography remained often be obtained using these techniques. As a an uncomfortable, if not painful, experience result of improvements in these noninvasive because of the use of conventional ionic contrast vascular imaging techniques, it is possible that agents. The introduction of digital subtraction the need for conventional diagnostic catheter angiography (DSA) and nonionic contrast angiography will become obsolete. However, at agents in the last two decades of the 20th present, despite the reduced requirement for century made arteriography much more accept- angiography for general diagnostic work, there able to patients and their doctors. Digital sub- remains a role for angiography in the investiga- traction angiography allowed smaller amounts tion of vascular disease, either as a first-line of contrast to be used, and the newer contrast investigation or following other imaging inves- agents rarely produced intense heat or pain. The tigations.Also angiography remains paramount combination produced fewer systemic side as part of all percutaneous endovascular inter- effects as well. ventional techniques. At the same time, attention was directed toward less invasive therapeutic interventions, such as Dotter’s technique of sequential dilation Imaging Modalities for atherosclerotic occlusive lesions. The devel- opment of the balloon angioplasty catheter, first The imaging techniques available for the inves- described by Gruntzig and Hopff in 1974, her- tigation of vascular diseases are best divided alded an era in which a range of manifestations into invasive (i.e., catheter angiography) and of arterial occlusive disease became amenable noninvasive techniques. The following is a brief to treatment using percutaneous vascular inter- description of the commonly used modalities. ventional techniques. There followed develop- ments of a range of techniques for treating Catheter Angiography arterial occlusive disease such as arterial , catheters, lasers, and thrombolysis. Catheter angiography is an x-ray investigation From these, implantable devices such as inferior in which a contrast agent is injected into the vas- vena cava (IVC) filters and stent grafts for cular system via a catheter, and sequential x-ray aneurysmal disease were developed. All these exposures are performed. The x-ray receiver can 27

RADIOLOGICAL INVESTIGATIONS be plain x-ray film (older machines), but are trast media. For the majority, the effect is now almost universally digital systems, using an temporary. However, in high-risk patients the image intensifier or a flat panel detector. Older incidence of contrast-induced nephropathy is machines using cut plain x-ray films were cum- around 20% to 30%, and in a significant number bersome and difficult to operate. In addition, of cases the effect is permanent and nonre- the postprocessing facilities were very limited. versible. High-risk groups are those patients In contrast, digital systems are easy to operate, with preexisting renal impairment, diabetes require lower contrast dosage, produce better mellitus, dehydration, on nephrotoxic drugs, contrast resolution, have real-time display, and a history of multiple myeloma. These and have facilities for image manipulations, patients should be well hydrated prior to the such as pixel shifting and digital subtraction procedure, if necessary by the administration of angiography. intravenous saline, and their renal function should be checked 48 hours postprocedure. Contrast Agents Recently, some studies involving a small number of patients suggest that acetylcysteine The primary aim of the contrast agent is to allow and calcium channel blockers may reduce the imaging of vessel anatomy and morphology. incidence of contrast-induced nephropathy During fluoroscopy, x-ray contrast agents act (Kay et al., 2003). There is also evidence that at- by changing the attenuation between tissues. risk patients, particularly those with diabetes Iodinated agents and gadolinium have a higher mellitus, have a lower incidence of contrast- density than surrounding tissue, whereas induced nephropathy following the use of carbon dioxide has a lower density. recently introduced iso-osmolar contrast agents (Aspelin et al., 2003). There is also a risk of Iodinated Contrast Agents potentially fatal lactic acidosis if a patient taking metformin develops acute renal impair- The most widely used contrast agents for ment following the administration of iodinated catheter angiography are the water-soluble contrast. Ideally metformin should be discon- iodine-based agents. They can be divided into tinued at the time of, or prior to, the procedure ionic and the newer nonionic agents. Nonionic and withheld for 48 hours subsequent to the agents have the advantage of considerably procedure and reinstituted only after renal reducing the risk of adverse reactions to con- function has been reevaluated and found to be trast, but are more expensive. In the United normal. Kingdom the low-osmolar nonionic agents are used almost exclusively for intravascular proce- Other Agents dures. These agents are denser than blood, and the commonly used strength for diagnostic and Mainly because of the risk of nephrotoxicity interventional work is 300mg of iodine per with iodine-based agents, CO2 has recently milliliter of contrast. For hand injections, this been advocated as a vascular contrast media for strength of contrast is usually diluted 50:50 patients with renal impairment. It can also be with saline. Patients with a previous history of used when there are contraindications to iodi- adverse reactions to these contrast media, a nated contrast such as a history of iodine or strong history of allergic disease, or a hyper- contrast allergy. Minor alterations in techniques sensitivity to iodine are at risk of developing a and software are required for CO2 angiography. severe allergic reaction to these contrast agents. Although dedicated CO2 pump injectors are Other investigative modalities that do not available, these are expensive to purchase. require iodinated contrast media such as MRI Cheaper alternative techniques, not requiring a or ultrasound should be considered, or alterna- dedicated pump injector, have been described tive non–iodine-based contrast such as carbon and used with complete safety if appropriate dioxide (CO2) or gadolinium, as described measures are utilized (Snow and Rice, 1999). below. The other major problem with iodinated Stacking software is required to overcome frag- contrast is nephrotoxicity. Overall, contrast- mentation of the CO2 gas column by the flowing induced nephropathy occurs in approximately blood (Fig. 4.1). For adequate imaging of the 5% of all procedures requiring iodinated con- tibial and distal arteries, elevation of the feet by 28

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Figure 4.1. Carbon dioxide angiography showing the application of stacking software to remove the beading effect seen in panels A and B.

10 to 20 degrees may be necessary. Unlike raphy (as opposed to MRI) it is potentially more iodine-based agents,CO2 can be administered in nephrotoxic than iodinated contrast (Thomsen large quantity, even in patients with pulmonary et al., 2002). It can be useful in patients with disease, without any adverse effect. The CO2 gas other contraindications to iodinated agents, uti- displaces the blood and appears radiolucent in lized as a problem solver to answer specific relation to surround tissue (negative contrast questions that cannot adequately be defined by agent). Unfortunately, due to its low density, CO2 CO2 angiography. Because of dose limitations angiography has a lower contrast resolution (maximum 0.3mmol/kg), careful planning is compared to iodine-based agents and hence required prior to its use. produces a poorer image quality, particularly Even with the introduction of smaller in the small peripheral vessels. Furthermore, catheters and safer contrast agent, the role of CO2 gas can cause the vapor lock phenom- contrast catheter angiography as the primary enon, a condition in which the gas is collected investigation tool of vascular diseases is dimin- over the most anterior aspect of an artery, ishing due to its many drawbacks (Table 4.1). In in particular the aorta, causing poor visualiza- the future, it will be employed mainly as part of tion of the mesenteric arteries and producing an interventional procedure or in special diag- temporary abdominal pain, thought to be sec- nostic situations. ondary to bowel ischemia. Finally, CO2 angiog- raphy is contraindicated for “above-diaphragm” Computed Tomography angiography, because of the risk of cerebral embolization. Until relatively recently, the images obtained Gadolinium chelate, an MRI contrast agent, from CT examinations were of suboptimal can also be used as an intravascular contrast quality for the assessment of most vascular dis- media. However, it is a poor radiographic con- eases except aneurysmal conditions. This was trast agent, and it should not be used in patients due to the long examination time (minutes) and with renal impairment, as there is evidence that thick slice width (5 to 10mm); hence, images at the doses required for conventional angiog- were subjected to movement artifacts and were 29

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Table 4.1. Complications of angiography have multiple banks of detectors (up to 64), Contrast medium–related complications allowing several slices to be acquired with Minor adverse reactions: common, but rarely life each revolution of the scanner. The volumetric threatening (e.g., urticaria, nausea) data obtained from recent scanners can be Major adverse reactions: rare, but serious processed and displayed as multiplanar refor- (idiosyncratic anaphylactoid reactions) mats (MPRs), maximum intensity projections Local vascular changes (e.g., effects on red (MIPs), or surface shaded displayed (SSD) (Fig. cells/coagulation) 4.2). Details about these reconstructions are Systemic vascular changes (e.g., increases in blood beyond the scope of this chapter, but it is prob- volume) Individual organ toxicity (e.g., renal) ably fair to say that MPR is most frequently used Access site complications clinically. Hemorrhage With the new generation of multidetector Intramural or perivascular injection of contrast scanners, the best spatial resolution of the Vascular thrombosis (following or local images obtained is around 0.5mm, which is ade- trauma) quate for assessing most vascular systems. Peripheral embolization However, as with contrast angiography, the Vascular stenosis or occlusion main limitation of CT examinations is the formation requirement of large volumes (100 to 150mL) of Arteriovenous fistula potentially nephrotoxic iodine-based contrast Local infection Nerve damage agent even with the new generation machines. Damage to other local structures Alternative contrast agents such as gadolinium Catheter and general complications can be used for CT, but produce less contrast Air embolism and are more expensive. Catheter thrombus embolization Currently, the main roles of CT in relation to Dissection or perforation of vessels vascular diseases are (1) diagnosis of aortic Organ ischemia or infarction secondary to spasm, dissection, or embolization Fracture and loss of guidewire or catheter fragments Catheter knot formation Mistaken injection of toxic material (e.g., skin cleansing agent) Vasovagal reactions Adverse reaction to local anesthetic or other drugs

of low spatial resolution. These shortcomings prohibited the high-quality reconstruction often necessary for vascular studies. However, the introduction of spiral/helical CT shortened the examination time dramatically to less than 30 seconds and allowed the use of thin collima- tion (i.e., slice thickness). This short acquisition time meant the examination could be per- formed in a single breath-hold, reducing the motion artifact that was frequently encountered with older scanners. Thin collimation in turn improved spatial resolution, further enhancing image quality. These factors were further improved with the introduction of multislice/ detector spiral CT. In comparison to the first- Figure 4.2. Surface shaded reconstruction showing the rela- generation spiral CT scanners that have a single tionship of an infrarenal abdominal aortic aneurysm to the bony bank of x-ray detector, multidetector scanners landmarks. 30

VASCULAR SURGERY aneurysms, (2) assessment for open or en- poor display of intraluminal thrombus and dovascular treatment of aortic aneurysm, (3) calcification of the arterial wall. The latter two endovascular stent graft surveillance, and (4) limitations are important to consider in vascular trauma.Although CT provides accurate endovascular procedures, such as aneurysm imaging of visceral and peripheral arteries, stent grafting. In addition, MRA has the ten- magnetic resonance angiography (MRA), which dency to over-grade the degree of stenosis. has none of the disadvantages of CT (i.e., Hence, in most units, confirmatory catheter nephrotoxic contrast agent and ionizing radia- angiography is routinely performed prior to tion), is more widely accepted by clinicians. intervention in cases where the MRA has shown Because magnetic resonance provides poor significant stenotic disease. visualization of calcified arteries, a combination Currently, the main roles of MR are for the of MRA and noncontrast CT is often required in investigations of aortoiliac disease, visceral these cases. arteries, and extent of arteriovenous malforma- tions. In addition, as it involves no ionizing Magnetic Resonance Angiography radiation, MR is the most appropriate imaging modality for young patients requiring long- Prior to the advent of gadolinium-enhanced term follow-up, such as those with aortic dis- three-dimensional (3D) MRA by Prince and section, aortic root replacement surgery, or coworkers,MRA played a small role in the inves- aortic coarctation. Although MR is not widely tigations of vascular diseases, mainly because used at the moment as the primary imaging the images obtained were of poor quality due to modality for vascular disease, with further movement and turbulence-induced artifacts advances in software and hardware designs (Prince et al., 1993). The use of gadolinium expected in the future, it will become an ideal chelate as a contrast agent shortens the exami- imaging tool. nation time significantly, allowing the examina- tion to be performed in a single breath-hold, reducing movement artifacts. In addition, Radiation Safety gadolinium-enhanced MRA is not susceptible to the flow artifacts that plague noncontrast MRA. X-rays are an ionizing radiation, interacting The data range in 3D MRA is acquired as a with water molecules, producing radicals that continuous volume, and this allows 3D recon- cause cellular damage and death. The effect can struction of the images, producing images com- be immediate,for example,skin necrosis,or late, parable to catheter angiography. The resolution such as genetic mutation or cancer formation. It limit of current MR scanners is approximately 1 is important to bear in mind that radiation mm, which is adequate for the imaging of most exposure is cumulative and permanent; hence, arteries, including the pedal vessels. Visualiza- it is prudent that the exposure to x-rays be tion of smaller vessels is software dependent, minimized. There are several simple methods however, and MR images of distal vessels are to reduce the exposure to both patients and limited by contrast issues, as the gadolinium operators: dilutes as it travels distally and enhances the veins soon after the distal arteries. Despite these 1. Radiation exposure is proportional to issues, MRA of the infrainguinal vessels can be fluoroscopy time, and hence the most performed with adequate quality for planning effective way to reduce exposure is to distal bypasses in centers with very high quality reduce the fluoroscopy time. Use pulse MRI. mode rather than continuous mode when The main advantage of MRA, in relation to possible and plan cases in advance to CT, is the use of gadolinium as a contrast agent, obtain only the necessary views. which is safe and does not cause renal impair- 2. Increase the distance from the source. ment, except in rare cases. The current limita- Exposure decreases with the square of the tions of MRA are high cost, lack of availability, distance from the source (inverse square patient claustrophobia, narrow range of field law). of view (for example, it is unable to image the 3. Use lower magnification and careful entire aorta in one continuous acquisition), and collimation. 31

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4. Use posterior-anterior imaging, that is, the duplex examination is adequate as a first-line x-ray source is from the posterior of a investigation for the demonstration of the exter- supine patient. nal iliac arteries, femoral arteries, and even as 5. Position the image intensifier as close as distally as the tibial trifurcation. Conventional possible to the patient to reduce scatter. catheter angiography, MRA, or CT angiography 6. Use protective barriers such as table aprons, can be performed if the examination is of lead glass shields, as well as the usual lead suboptimal quality or if the assessment of apron,thyroid shield,and glasses. distal arteries is required, for example in cases where distal bypass surgery is considered. This The use of dosimeter badges by all persons depends on staff expertise and equipment avail- working with ionizing radiation is mandatory. ability in individual centers. In some centers In the United Kingdom, the badge must be posi- distal bypass decisions can be based on duplex tioned at waist level under the lead apron.Addi- arterial mapping, MRA or even CT angiography tional badges can be worn (such as on the (CTA), but currently most units still depend fingers or forehead) for specific exposed areas. on catheter angiography. In patients with sus- In the United States, badges are required either pected aortoiliac disease, duplex examination is outside the apron at the neck level, beneath the more difficult due to anatomical constraints. In lead apron, as in the U.K., or in both locations this situation, MRA or CTA is generally pre- (with finger badge an option). In the U.K. and ferred. If these two options are not available, an U.S., no individual working in the controlled angiogram can be performed via a catheter that area should receive doses in excess of (1) is positioned in the distal abdominal aorta. If 20mSv/year to the body, (2) 150mSv/year to the brachial or radial artery access is used, access lens, and (3) 500mSv/year to hands or forearm. should be obtained from the left arm to mini- Finally, although the use of dosimeters is man- mize the risk of embolic complications to the dated, it is the responsibility of the operator to cerebral circulation. wear and use them correctly. Catheter angiography is useful to diagnose vasculitic conditions such as thromboangiitis obliterans (Buerger disease). This condition Investigations of classically affects small and medium-size arter- ies and veins of the lower limbs in young Vascular Diseases smokers with a typical angiographic appear- ance. In patients with blue digit syndrome, This section is divided into system-based cate- catheter angiography may show the source of gories. Common conditions and appropriate emboli, typically atherosclerotic plaques in the investigations for each system are discussed. aorta or iliac arteries. However, CT or other noninvasive modalities are preferred for the initial evaluation in blue digit syndrome, Peripheral Vascular Disease because the catheter-based modalities carry the (Lower Limb) risk of further atheroemboli. Finally, although conventional catheter This is the most common of all vascular condi- angiography plays an ever-diminishing role as tions, accounting for the majority of the work the primary diagnostic tool in the investigation load in any vascular unit. Clinically, this condi- of peripheral vascular disease (PVD), it still has tion is best divided into two subcategories: (1) a few advantages in comparison to noninvasive patients with symptoms of claudication without techniques. Direct pressure measurement can any tissue loss or rest pain; and (2) patients be performed in equivocal stenosis (>10mmHg with rest pain or tissue loss, suggesting limb- systolic gradient is considered significant), with threatening ischemia. In those patients with the use of enhanced gradients in cases of possi- symptoms that are severe enough to warrant ble “subcritical” stenosis [by the use of distal intervention, further investigation is justified. vasodilators such as glyceryl trinitrate (nitro- However, most claudicants do not require inter- glycerin in the U.S.) or papaverine], as well as vention and are treated conservatively, and thus allowing intervention to be performed in the further imaging is not necessary. In most cases, same sitting. 32

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Upper Limb Vascular Diseases ered appropriate (see Chapter 3). The procedure is relatively easy to perform with good accuracy Upper limb vascular diseases are far less fre- in experienced hands. In addition, it provides quently encountered than those of the lower morphological assessment of the plaque. Hence, limb. These can usually be attributed to subcla- in many vascular centers, duplex examination vian steal syndrome, embolic disease, or blue is the sole radiological investigation prior to digit syndrome (distal embolization), and rarely . However, when endo- due to diffuse atherosclerotic disease commonly vascular treatment is an option, it is important seen in the lower limbs. Duplex ultrasonogra- that the entire carotid artery is assessed for phy is useful as a preliminary test.Although it is synchronous stenotic disease, tortuosity, and anatomically not possible to visualize the first a favorable angle of origin of the vessel to be part of the subclavian artery directly, waveform treated (Fig. 4.3). These factors determine if analysis of flow in the distal segments may endovascular treatment is feasible. Unfortu- reveal changes (such as damped signal or spec- nately, duplex examination cannot answer all tral broadening) that are suggestive of proximal these questions, and in our unit we presently occlusion or stenosis. In addition, duplex exam- rely on conventional arch aortography for full ination may detect flow reversal in the vertebral assessment (selective catheterization should not artery, which suggests a steal phenomenon and be required). However, it is likely that as is a good indication of significant ipsilateral improvements in MRA and CTA continue to be proximal subclavian artery stenosis or occlu- made, the full characterization of carotid steno- sion. Magnetic resonance angiography is widely sis, the arch vessels, and cerebral circulations accepted for the visualization of arch vessels,but will be of sufficient quality to eliminate the aortic pulsation artifact may obscure anatomi- requirements for catheter angiography to deter- cal detail at the origins of the great vessels.Com- mine whether a patient is a good candidate for puted tomography angiography is useful but endovascular intervention. subjected to beam-hardening artifacts from the Carotid body tumor is a rare condition that thoracic cage and contrast in the venous system, classically presents as a painless pulsatile mass both of which are in close proximity to the below the angle of the jaw, and is laterally arteries of interest. Ultimately, catheter angiog- mobile but fixed vertically. Approximately 10% raphy is still the definitive test for the investiga- of cases are bilateral. The typical ultrasonic tions of patients with upper limb ischemia. It is feature is an oval mass splaying the carotid pertinent that a flush aortic arch angiogram is internal and external carotid arteries. This mass performed in two planes (left and right anterior enhances avidly on CT or MR examinations. oblique), as origin disease is frequently missed if only one projection is obtained. Pulmonary Arteries A rare cause of upper limb ischemia is Takayasu (pulseless disease), a condi- There are few medical conditions that require tion most commonly seen in young female the imaging of the pulmonary vasculature. Most Asians. It is a granulomatous disease involving frequently this is required for suspected acute major arteries, in particular the aortic branches pulmonary embolic (PE) disease or as part of and pulmonary arteries. Clinically, the patient is the investigation of , to systemically unwell with symptoms and signs of exclude chronic thromboembolism. In the limb ischemia or renovascular hypertension. majority of cases with suspected acute PE, the Radiological features suggestive of the condi- initial investigations should consist of a chest tion are enhancing thickened arterial wall on radiograph and a radionuclide ventilation- CT, segmental stenotic or occlusive disease of perfusion (V/Q) scan or a CTA. Unfortunately, major arteries, and aneurysm formations. up to 50% of V/Q scans are of no diagnostic value, and in these circumstances supplemen- Carotid Arteries tary investigations are required. Previously, catheter angiography was the imaging modality Duplex ultrasonography examination is the pre- of choice, but with the advent of spiral CT the liminary test for patients with suspected carotid role of catheter angiography is limited to situa- artery stenosis in whom intervention is consid- tions such as massive PE, where immediate 33

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Figure 4.3. Tortuous common and internal carotid arteries (arrow), a contraindication to carotid artery stenting.

intervention may be required. Although CTA is tered immediately following the confirmation of undoubtedly accurate for the diagnosis of mod- the diagnosis. Furthermore, it is possible to erate to large emboli, it is limited by its inabil- insert an IVC filter at the same time to prevent ity to reliably diagnose subsegmental embolism, further embolism, if this remains a risk. particularly with the older single-slice spiral Pulmonary angiography is also indicated in scanners. However, the clinical significance of patients in whom noninvasive diagnostic tests subsegmental PE is uncertain and may have remain inconclusive and a reasonable suspicion only minimal impact in the long-term outcome. for PE exists. In this situation, pulmonary The results of ongoing outcome studies where angiography is aimed at excluding PE, thus patients are managed on the basis of multide- allowing withdrawal of anticoagulant therapy tector/slice helical CT findings are eagerly with its inherent bleeding risk. In patients in awaited. whom the consequence of bleeding is unfor- Magnetic resonance angiography has not giving, for instance following recent neuro- been thoroughly evaluated as a tool for the diag- surgery, pulmonary angiography can provide a nosis of PE, but a recent study showed that it has definitive diagnosis. The disadvantages of pul- reasonable accuracy in comparison to catheter monary angiography are that it is invasive and angiography (Haage et al.,2003).However MRA, uses nephrotoxic contrast agents. Nevertheless, as with CTA, is limited by the poor visualization the safety of this technique has improved dra- of subsegmental arteries, and resolution tends matically over the past 10 years. Current esti- to be approximately half that of CT in most mates of mortality and morbidity are around institutions. Magnetic resonance angiography is 0.03% and 0.47%, respectively, in experienced unlikely to be widely used for the diagnosis of hands. PE until further data are available (Haage et al., Pulmonary arteriovenous malformation 2003). (AVM) is a rare condition in which there is an In certain situations, the catheter pulmonary abnormal large vascular communication angiogram remains the investigation of choice. between the pulmonary artery and vein. This Patients with acute massive PE and cardiorespi- allows shunting of blood from the pulmonary ratory instability should proceed directly to circulation to the systemic circulation and catheter angiogram, where treatment such as hence the risk of complications such as cere- thrombectomy or thrombolysis can be adminis- brovascular accident and cerebral abscess. The 34

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Figure 4.4. Coil embolization of pulmonary arteriovenous malformation (AVM). A: Pulmonary angiogram shows an AVM in the periphery of left lobe (arrow). B: Selective angiogram demonstrates the characteristic early draining vein. C: Angiographic appear- ance after successful embolization.

AVM can be solitary (40% of cases) or multiple, Technetium 99m (99mTc) sulfur colloid or 99mTc- often associated with hereditary hemorrhagic labeled erythrocytes are used to localize mild- (Rendu-Osler-Weber syndrome). to-moderate intermittent bleeding, particularly Diagnosis can be reliably confirmed by CT or in the lower GI tract, and 99mTc pertechnetate is MR examinations,showing a vascular mass with used to detect Meckel’s diverticulum. Selective a large feeding artery and draining vein (Fig. catheter angiography may reveal the exact site 4.4). Catheter angiogram is indicated only as a of hemorrhage but this is highly dependent on part of the current treatment of choice, i.e., the timing of the procedure. Many investiga- embolotherapy. tions turn out to be false negatives (reported accuracy of 40% to 90%), as the patients are not Mesenteric Arteries actively bleeding at the time of investigation. Nonetheless, the tests may still show areas of The main indications for the investigation of abnormal vascularity such as angiodysplasia. In mesenteric arteries are gastrointestinal (GI) addition, endovascular treatment such as bleeding, intestinal angina, and mesenteric embolization or vasopressin infusion may be artery aneurysms or pseudoaneurysms. For GI initiated, and, it is hoped, avoid the high mor- bleeding, endoscopy is the first-line investiga- bidity and mortality (up to 30%) of emergency tion.If the bleeding site or cause is not identified surgery. The treatment may permanently stop (up to 40% of endoscopic examinations), the the bleeding or allow a window of opportunity patient should have a radionuclide test if the to stabilize the patient prior to definitive surgi- hemorrhage is not life threatening, or urgent cal resection if deemed necessary. selective catheter angiography if the patient is Although atheromatous disease of the mesen- hemodynamically unstable and actively bleed- teric arteries is common, mesenteric angina is a ing. Radionuclide investigations are more rare entity. This is because there are numerous sensitive than catheter angiography for the large collaterals between the mesenteric arter- investigation of GI bleeding (isotope remains in ies, and hence the symptoms of mesenteric the vascular system far longer than contrast angina only manifest if there is severe stenosis agent), but less accurate in identifying the exact or occlusion in two of the three mesenteric anatomical site or the nature of the disease. arteries (celiac, superior mesenteric, and infe- 35

RADIOLOGICAL INVESTIGATIONS rior mesenteric arteries). The first-line investi- patients with suspected FMD have MRA as the gation should be duplex ultrasonography, as it first-line investigation, followed by catheter has excellent diagnostic value in many institu- angiography if the MRA is of suboptimal tions. The origins of celiac and superior mesen- quality or there is strong clinical suspicion of teric artery are relatively straightforward to FMD. Although CTA is accurate for assessing assess. However, the inferior mesenteric artery , it is subjected to a similar is frequently not seen due to overlying bowel drawback as catheter angiography, that is, gas. Because of this, many radiologists prefer requiring iodinated contrast media and ionizing MRA as the primary investigational modality radiation. Duplex examination is the initial for this condition. The 3D acquisition allows imaging modality of choice in many institutions accurate assessment of the ostial disease with due to its low cost and relatively high accuracy sensitivity and specificity comparable to that of for renal artery stenosis, but it is more prone to catheter angiography. Computed tomography missing duplicate renal arteries, and it is highly angiography is also being used as an adjunctive operator- and patient-dependent, with up to a diagnostic modality in some institutions, pri- 15% technical failure rate. marily to aid in evaluation of calcific aortic With the current shortage of cadaver renal plaque that is not seen well on MRA, but may donors, living-related renal transplant surgery have a substantial impact on the approach to has become a common procedure. Previously, surgical intervention. Currently, catheter angio- the donors had to undergo catheter angiogra- graphy is usually reserved for cases in which phy, ultrasonography, and intravenous urogra- other imaging modalities are equivocal,or when phy as part of the assessment. Currently, MR is endovascular intervention is considered. the imaging method of choice as it provides the Mesenteric artery aneurysm is an uncommon most comprehensive and accurate assessment of condition, and is best assessed with cross- the donor in one sitting. It allows anatomical sectional studies such as CT. This allows the and morphological evaluation of the renal identification of the vessel of origin, the size of parenchyma, veins, arteries, and ureters with the aneurysm, and the mass effect on the sur- confidence. In addition, it may show other rounding structure. Catheter angiography can intraabdominal pathologies such as adrenal or then be performed as part of the embolization pelvic masses. Computed tomography angiog- treatment or for evaluation of potential raphy with 3D reconstruction can also be used aneurysms in the mesenteric arcades. in patients who are known to have normal renal function, as is true for most potential renal donors. Renal Arteries Aortic Aneurysms and Dissections The main indications for imaging of the renal arteries are (1) diagnosis of renal artery steno- The conventional treatment for patients with sis, most commonly atherosclerotic or fibro- aneurysmal disease of the aorta is surgical. muscular dysplasia (FMD); and (2) evaluation Patients with abdominal aortic aneurysms of potential live renal donors. Although conven- (AAAs) or thoracic aortic aneurysms of greater tional catheter angiography is still considered than 5.5 or 6.5cm in diameter, respectively, the gold standard, it involves the use of nephro- are generally best treated, depending on the toxic contrast agent in a group of patients with patient’s fitness for surgery, because of the a high incidence of preexisting renal impair- increasing risk of rupture above these sizes. In ment, and hence is employed only in cases most cases, CT examination alone is adequate where other tests are unavailable or inconclu- to provide all the information needed prior to sive. In many institutions MRA is currently the open surgical repair. Computed tomography investigation of choice in patients with sus- shows the relation of visceral arteries to the pected renovascular disease, primarily due to aneurysm sac, the size and extent of the the lack of nephrotoxicity with gadolinium- aneurysm, and other conditions that may pre- chelate. It has high sensitivity and specificity for clude surgical repair, such as horseshoe kidney. the assessment of ostial disease, but is unproven In the early 1990s endovascular aneurysm for distal stenosis such as in FMD. In our unit, repair (EVAR) revived the role of catheter 36

VASCULAR SURGERY angiography for the assessment of aortic been recommended for establishing migration, aneurysms. Catheter angiography began to but this is best performed on CT. Triple-phase diminish again, however, as spiral CT with 3D CT examinations (nonenhanced, arterial phase, reconstruction and specialized software in the and delayed “venous” phase) allow serial meas- mid-1990s allowed high-quality reconstructions urements of aneurysm sac diameters, monitor- not previously possible. Accurate preoperative ing of the integrity and position of the device, imaging is crucial to ensure proper selection of and detection of an endoleak (reperfusion of patients, stent-graft types, and potential intra- the aneurysm sac) (Fillinger, 1999). Three- operative adjuncts such as coil embolization, dimensional reconstruction with volume iliac angioplasty, renal stenting, femoral measurements is the most sensitive method endarterectomy, and iliac conduits. To eliminate for detecting aneurysm sac size changes, but the need for catheter angiography preopera- requires expertise in image segmentation or tively, work focused on 3D reconstruction of CT outsourcing to a commercial entity. It may allow and MR data, with specialized software for earlier detection of problems that require inter- detailed measurements and even endograft vention after EVAR or earlier reassurance to the simulations preoperatively. Currently, CT or MR patient and less frequent surveillance in suc- with 3D reconstruction and computer-aided cessful repairs (Fillinger, 1999; Kay et al., 2003). measurement, planning, and simulation is the Duplex ultrasound is a useful adjunct for the standard for imaging prior to EVAR, with meas- detection of endoleak, without the risk of con- urement accuracy and outcomes equal or supe- trast nephrotoxicity and ionizing radiation. rior to catheter angiography and without the However, it may not show the source of morbidity or expense (Broeders et al., 1997; endoleak and is unable to assess stent-graft Fillinger, 1999, 2000). The main disadvantages of integrity accurately. Three-phase contrast- MR are the difficulty in visualizing thrombus enhanced MRA serves as an attractive alterna- and calcification, important points to be con- tive to CTA in patients with renal impairment sidered, as thrombus in the neck of the and relative contraindications to iodinated con- aneurysm may preclude endovascular repair. trast media. There is evidence that it is superior Nevertheless, future advances in MR technolo- to CT in depicting small type 2 (collateral) gies are expected to resolve these problems. endoleaks. Unfortunately, it is not suitable for Although the technical success of stent-graft stainless steel devices, which cause severe image implantation is well established, only modest degradation secondary to metal artifacts. Cur- data are available for midterm results, and data rently, the role of catheter angiography is to on long-term efficacy and safety are not yet characterize endoleaks (inflow and outflow established.The goals of postprocedure imaging channels) detected by the noninvasive tests or to are to (1) confirm appropriate stent-graft place- further evaluate sacs that appear to have ment, (2) assess the effectiveness of aneurysm enlarged without an endoleak. exclusion, (3) follow the aneurysm sac size, and is a condition in which a (4) detect device failure and/or migration. spontaneous tear of the tunica intima allows cir- Because late complications have been observed, culating blood to gain access to the tunica lifelong follow-up is felt to be essential at the media, splitting it longitudinally. The objective present time. The current imaging strategy of imaging is not only to diagnose the condition should include plain radiographs of the stent but also to localize the site of entry, assess the graft in four projections (anterior-posterior, extent of dissection, and identify associated lateral, and two obliques) and CT angiography complications. The potential complications that at 1, 6, and 12 months postoperative, and then may occur are occlusion of major aortic annually. More or less frequent imaging may branches such as coronary and visceral arteries; be recommended depending on the imaging aortic valve insufficiency; rupture into the peri- results (e.g., endoleak or migration), type of cardial sac, mediastinum, or pleural cavity; stent graft, and manufacturer recommenda- and aneurysm formation in the long-term. At tions. Plain radiographs are an excellent and present, the imaging modality of choice for inexpensive means to assess the metallic stent- acute dissection is CT angiography. It has excel- graft frame for structural failure, angulation, lent sensitivity and specificity in comparison to and kinking. Plain radiographs have typically catheter angiography, which is considered the 37

RADIOLOGICAL INVESTIGATIONS standard of reference. However, it is vital that nary investigation is a chest radiograph. It may the examination be performed in the arterial show features suggestive of transection, such as phase of contrast enhancement, as failure to do a widened mediastinum, apical cap, and dis- so may lead to misinterpretation of a dissection placement of the trachea, left main bronchus, or as an aneurysm. Transesophageal ultrasonic nasogastric tube. A normal chest x-ray does not examination is a useful adjunct, showing the exclude transection, but will diagnose condi- presence or absence of aortic valve incompe- tions such as pneumothorax or hydrothorax. tence and pericardial effusion, and confirming Arterial phase contrast-enhanced spiral CT with the presence of the intimal flap. Magnetic reso- fine collimation is the most widely used modal- nance is as accurate as CT, if not more so, in ity for the imaging of aortic transection. Fea- diagnosing acute dissection. However, it is tures of aortic injury are the presence of an rarely employed because of the lack of immedi- abrupt change in aortic contour,false aneurysm, ate availability, the delay from bedside to intimal flap, or extravasation of contrast. Medi- scanner, the long examination time, the limited astinal hematoma is a frequent finding in trau- access to the patient, and the restricted moni- matic chest injury, but in the majority of cases, toring of vital signs, which is especially prob- the source of hematoma is the azygos or hemi- lematic in these often hemodynamically azygos veins and paraspinal and intercostals unstable patients. vessels rather than aortic injuries. Although catheter angiography is still considered the standard of reference for investigation of aortic Vascular Trauma transection, it is employed only when the CT examination is equivocal or as part of the Vascular injuries can occur in a number of ways, endovascular treatment. When performing such as motor vehicle accidents, knife or catheter angiography, it is vital that at least two gunshot wounds, or iatrogenically. In most projections of the arch and descending aorta be cases, the history and clinical features provide obtained prior to pronouncing the investigation the diagnosis. Hemodynamically unstable normal. In addition, an awareness of ductus patients usually proceed immediately to the diverticulum is required. This is the vestigial operating room for control of the hemorrhage. remnant of the ductus arteriosus and is present If the patient is stable enough, imaging can be in approximately 10% of the population. This used to confirm hemorrhage or injury, localize anatomical variant appears as a small bulge on the site, and assess the severity. In addition, the medial wall of the aorta, just inferior to the treatment options can be planned from the origin of the left subclavian artery, and is fre- information acquired, and in some cases quently misinterpreted as a false aneurysm. catheter-based therapeutic intervention can be performed. Direct vascular injuries in a stable patient are often best investigated initially by Conclusion CT examination. One major advantage of con- trast-enhanced CT over ultrasound is the ability We have presented an overview of available to identify the exact site of bleeding and poten- imaging techniques in use in vascular radiolog- tially help plan the approach for surgical or ical practice, emphasizing the move away from endovascular intervention. invasive techniques and toward noninvasive Aortic injury occurs most often following a techniques for diagnosis of vascular diseases. rapid deceleration injury, and the vast majority The most important contemporary approaches of cases are due to motor vehicle accidents. and therapies have also been described, Complete rupture accounts for 85% of cases, showing the important role these techniques and most patients do not survive. The remain- now play in the management of a range of vas- ing 15% have incomplete rupture (contained cular disease processes. rupture) and they require immediate treatment, as half of them will progress to complete References rupture within 24 hours. The most common site of injury (90%) is at the aortic isthmus, just Aspelin P,Aubry P, Fransson SG, Strasser R, Willenbrock R, distal to the left subclavian artery. The prelimi- Berg KJ. (2003) N Engl J Med 348:491–9. 38

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Broeders IA, Blankensteijn JD, Olree M, Mali W, Eikelboom Kay J, Chow WH, Chan TM, et al. (2003) JAMA 289:553–8. BC. (1997) J Endovasc Surg 4:252–61. Prince MR, Yucel EK, Kaufman JA, Harrison DC, Geller SC. Dormandy JA, Rutherford RB. (2000) J Vasc Surg 31:S1– (1993) J Magn Reson Imaging 3:877–81. S296. Snow TM, Rice HA. (1999) Clin Radiol 54:842–4. Fillinger MF. (1999) Surg Clin North Am 79:451–75. Thomsen HS, Almen T, Morcos SK. (2002) Eur Radiol 12: Fillinger MF. (2000) Semin Vasc Surg 13:247–63. 2600–5. Haage P, Piroth W, Krombach G, et al. (2003) Am J Respir Crit Care Med 167:729–34. 5 Bleeding and Clotting Disorders Vivienne J. Halpern and Frank C.T. Smith

Bleeding and clotting disorders have major a history of myeloproliferative, myelodysplastic, implications for the effective management of and lymphoproliferative disorders may also vascular patients. Such disorders can influence have increased bleeding through several mech- disease progression, perioperative complica- anisms, which may not appear in routine pre- tions, graft patency, limb salvage, and wound operative testing. Renal failure predisposes to healing. Most of these disorders are relatively bleeding tendencies based on platelet dysfunc- rare, and diagnosis requires an index of clinical tion, whereas, for instance, recent splenectomy suspicion combined with a need to obtain a may induce thrombocythemia predisposing to relevant medical history and appropriate abnormal clotting. An abnormal history of clot- specialized investigations. Correct and timely ting, such as multiple episodes of deep venous treatment may help prevent some of the com- thrombosis (DVT), may warrant screening for plications associated with these disorders. This thrombophilia. chapter reviews the presentation, diagnosis, Medications can influence both bleeding and management of some of the more common and clotting. Commonly used drugs such as disorders. Medications frequently associated aspirin and other nonsteroidal antiinflamma- with abnormal bleeding or clotting are also tory drugs (NSAIDs) affect platelet function, as discussed. do Aggrenox and Plavix. Herbal remedies and various vitamin combinations may also increase bleeding risks (Table 5.2). Furthermore, malnu- History, Physical and trition and vitamin deficiencies, such as vitamin C deficiency, may contribute to abnormal bleed- Laboratory Evaluation ing tendencies. Estrogen or estrogen-like med- ications including phytoestrogens predispose Recognition of a patient with a bleeding or to thrombotic episodes. PC-SPES is an herbal clotting disorder involves taking an adequate preparation with several components used for history. A screening questionnaire, such as that treatment of prostate carcinoma. It contains provided in Table 5.1 is useful and may help to phytoestrogens, which may induce thrombosis. direct further investigation. Obtaining a history However, it also contains Baikal skull cap of mucosal bleeding involving epistaxis, gum (Scutellaria baicalensis georgi), which is a bleeding, or menorrhagia may be more consis- coumarin (a naturally occurring group of tent with platelet disorders (thrombocytopenia, substances, structurally similar to warfarin). von Willebrand disease, etc.) than, for instance, These examples illustrate the importance of bleeding into a joint or muscle, which occurs querying the use of herbal medications as well more commonly with hemophilia. Patients with as more conventional pharmacotherapies when

39 40

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Table 5.1. Screening survey for abnormal bleeding or clotting Do you suffer from a bleeding disorder? Do you have bleeding from the gums or from the nose? Have you ever coughed up or vomited blood? Do you notice easy or spontaneous bruising or does it take you a long time to stop bleeding when cut? Do you have excessive bleeding with menstrual cycles? Have you had any blood in the urine or with stools? Have you had any bleeding into muscles or joints? Have you had a tooth extraction or any other procedure after which bleeding has taken a long time to stop? Have you needed to receive any blood products, plasma, or vitamin K to help stop bleeding? Do you have any problems with your liver or kidneys? Has anyone in your family had any of the above problems? Have you or anyone in your family had a history of clots in the blood vessels, either artery or veins? Do you take oral contraceptives? Do you take aspirin or any medications for pain or arthritis? Do you take any steroid medications? Do you take any herbal medications or vitamins? Do you take Coumadin or other blood thinners? Do you take any medications to prevent stroke or heart attacks? Do you have any blood diseases?

Table 5.2. Common medications, herbs, and vitamins associated with increased bleeding Medication Mechanism of action When to stop preoperatively Medications that may increase bleeding Aspirin Inhibits platelet aggregation via 5–7 days before major surgery thromboxane B2 3–4 days before minor surgery Persantine Inhibits phosphodiesterase to increase Omit dose before surgery cyclic AMP Aggrenox Combined Persantine and aspirin: increased As aspirin effects of aspirin Plavix Irreversible binding to platelet inhibits ADP Stop 7–10 days before surgery binding to platelet NSAIDs Various mechanisms 24 hours prior to surgery Herbs/vitamins that may increase bleeding Feverfew Used for migraines, ? inhibits platelet Stop at least 1 week before surgery aggregation via thromboxane B2, may be irreversible Garlic Inhibits platelet function by inhibiting Stop at least 7–10 days before surgery thromboxane synthesis; may be irreversible Gingko Inhibition of platelet activating factor Stop at least 36 hours prior to surgery Ginseng Inhibits platelet aggregation; prolongs PT Minimum of 24 hours prior to surgery and PTT; may be irreversible Vitamin E May decrease platelet adhesiveness; may Unclear; should stop around effect vascular endothelium 5 days before surgery Willow bark Salicylate precursors Stop 7–10 days before surgery, similar to aspirin Oil of wintergreen Affects platelet function Meadowsweet flower

ADP,adenosine diphosphate; AMP,adenosine monophosphate; NSAID, nonsteroidal antiinflammatory drug; PT, prothrombin time; PTT, partial thromboplastin time. 41

BLEEDING AND CLOTTING DISORDERS assessing the patient with a bleeding or clotting Table 5.3. Thrombophilia screen disorder. Protein C levels Protein S levels Antithrombin III Investigations Factor V Leiden Activated protein C Standard preoperative investigations for most Lupus anticoagulant vascular surgery patients include prothrombin Anticardiolipin antibody time (PT),international normalized ratio (INR), Antiphospholipid antibody Homocysteine levels activated partial thromboplastin time (aPTT), Prothrombin 20210A mutation platelet count, and activated clotting time Factor VIII and XI levels (ACT). A platelet count of 50,000/mL should ensure adequate hemostasis, whereas a count of 10,000/mL or less may result in spontaneous bleeding. The aPTT evaluates the intrinsic and contact activation pathways of coagulation Bleeding Disorders with the exception of factors VII and XIII. This investigation is used to monitor the effects of Bleeding disorders may be secondary to abnor- treatment with heparin. The extrinsic pathway malities of plasma clotting factors, blood (factors II, V, VII, and X, and fibrinogen) is vessels, or platelets. Some hemostatic defects evaluated with the PT and INR. These tests involve more than one of these systems. are employed to check the effectiveness of oral anticoagulation with warfarin. Additional tests should be directed by the history and clinical picture. Table 5.4. Protocol for further investigation of abnormal preoperative blood tests The prevalence of inherited bleeding and clotting disorders is relatively rare. Patients with Repeat abnormal PT/INR, aPTT with 50:50 mix with a recurrent, familial, or juvenile history of DVT; normal plasma (mixing study) arterial thrombosis at a young age or without If then normal, undertake the following investigations: Normal PT/INR, increased aPTT: evidence of atherosclerosis; or thrombosis in an Test for factor deficiency: usually isolated XI, IX,VIII unusual location, such as mesenteric or cerebral Increased PT/INR, normal aPTT: veins, should be assessed for a hypercoagulable Test for factor deficiency: isolated VII or can be state.Recurrent graft failure whether in a bypass multiple or an arteriovenous fistula, when not explained Test for liver abnormalities by the presence of an anatomical lesion, may Look for vitamin K deficiency (malnourished patient, also imply a prothrombotic state. Components patient on prolonged antibiotics) of a thrombophilia screen include those listed in Increased PT/INR and aPTT: Table 5.3 (Donaldson et al., 1990). Test for factor deficiency: isolated X,V,prothrombin, Patients with a history of abnormal bleeding, fibrinogen, or can be multiple If abnormal mixing study, undertake the following but not requiring medication, should undergo investigations: routine preoperative investigations as above. Normal PT/INR, increased aPTT: Excessive or prolonged bleeding during surgical Test for inhibitor activity, especially for XI, IX,VIII procedures where routine preoperative testing Test for nonspecific inhibitors, e.g., antiphospholipid of PT,aPTT,and platelet counts was normal may antibodies represent a platelet functional abnormality, a Increased PT/INR, normal aPTT: dysfibrinogenemia, factor XIII deficiency, vas- Test for factor VII inhibitor cular endothelial disorders, other mild factor Test for nonspecific inhibitors (rarely cause isolated deficiencies (if >25% of factor present), or a- increase in PT/INR) antiplasmin deficiency. Surreptitious use of Increased PT/INR and aPTT Test for inhibitors of X,V,prothrombin, fibrinogen medication might also be considered. Where Test for nonspecific inhibitors abnormal preoperative investigations are encountered, there is a rationale for further aPTT, activated partial thromboplastin time; INR, international nor- tests. A protocol is suggested in Table 5.4. malized ratio; PT, prothrombin time. 42

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In normal hemostasis, the blood vessel con- fibrinogen to generate fibrin monomers, which stricts in response to injury to reduce bleeding. then polymerize and link to one another to form Circulating platelets adhere to subendothelial a chemically stable clot. Thrombin also feeds collagen that is exposed by injury, promoted by back to activate cofactors VIII and V, thereby release of tissue factor (TF) from the damaged amplifying the coagulation mechanism. vessel wall. Platelets bind von Willebrand factor Together platelet aggregates and fibrin form the (vWF) at the glycoprotein Ib receptor, stabiliz- clot that achieves hemostasis. The coagulation ing adhesion. Fibrinogen binds to platelet gly- cascade is illustrated in Figure 5.1. Any disrup- coprotein IIb/IIIa receptors forming bridges tion of these pathways may lead to increased between adjacent platelets and causing aggre- bleeding. gation. Activated platelets also release potent Features in the history and physical examina- aggregating agents to recruit more platelets. tion that may help to differentiate among factor Coagulation is initiated through the extrinsic deficiencies, platelet disorders, and endothe- pathway. Exposed endothelium releases TF, lial (blood vessel) dysfunction are listed in which complexes with and activates factor VII. Table 5.5. Factor VIIa then activates both the common pathway and the intrinsic pathway. The intrin- sic pathway requires factor VIII and factor IX to Inherited Disorders proceed to the common pathway. Von Wille- of Coagulation brand factor also forms a noncovalent bond with factor VIII and is essential for its survival Factor Deficiencies in the circulation. Von Willebrand factor also potentiates factor VIII activity in clot formation Hemophilia A and B represent 80% of inherited and protects it from proteolysis. In the final step bleeding diatheses. These are both sex-linked of the coagulation pathway, thrombin cleaves recessive deficiencies affecting mostly males.

Figure 5.1. The coagulation cascade. Under physiological conditions, tissue factor is not exposed to blood. However, after injury, tissue factor is exposed to blood and activates the extrinsic pathway by acting in concert with activated VII and phospholipids to convert factor IX to IXa and factor X to Xa.The “intrinsic pathway” includes activation of factor XII to XIIa, which activates factor XI to XIa, IX to IXa, and X to Xa. Factor Xa is the active cat- alytic ingredient of the prothrombinase complex, which includes factor Va and phospholipase and converts prothrombin to thrombin. Thrombin is a protease that cleaves fibrinogen to fibrin. The result- ing fibrin monomers polymerize, forming a clot. 43

BLEEDING AND CLOTTING DISORDERS

Table 5.5. The relationship of factor disorders, platelet and blood vessel (endothelial) dysfunction to aspects of clinical presentation Clinical picture Factor disorder Platelet dysfunction Endothelial dysfunction Onset of bleeding Delayed Immediate Immediate Duration of bleeding Prolonged Short Variable Precipitant of bleeding Often spontaneous Trauma Variable Site Joints, muscle, viscera Skin, mucous membranes, GI tract Skin, GI tract Family history Usually present (unless factor Absent Usually absent inhibitor) Drug-related Rarely Often Sometimes Sex predominance Usually male Often female Usually female Response to focal pressure No response Sometimes responds Responds Platelet count Normal Normal, low, or high Normal Prothrombin time Abnormal in cases of factor II, Normal Normal VII, IX, and X deficiency (and inhibitors) Partial Thromboplastin Abnormal with factor VIII Normal Normal time or IX deficiency (and inhibitors)

GI, gastrointestinal.

They are caused by factor VIII (classic hemo- concentrates are not available, cryoprecipitate philia) and factor IX (Christmas disease) or fresh frozen plasma (FFP) may be used. deficiencies, respectively. Hemophilia A is four The treatment for hemophilia B is similar, to six times more common than hemophilia using specific factor IX concentrates or factor IX B. Together they have a prevalence of about complex transfusion. The factor IX complex 20/100,000 in the United States and 9/100,000 to contains one unit of factor IX per milligram of 15/100,000 in Great Britain. protein with varying amounts of other vitamin The risk for bleeding depends on the degree K–dependent proteins. The concentrates are of factor deficiency. At levels less than 1% to preferred treatment. Again, loading dose and 2% of normal (severe disease), spontaneous maintenance doses are administered according bleeding is likely to occur and the aPTT is pro- to the given situation. longed. Patients may present with spontane- Another factor deficiency (vWF), which can ous soft tissue or intramuscular hemorrhage, present like hemophilia, occurs in von Wille- hemarthroses, hematuria, and spontaneous brand disease (vWD). Overall, this is the most retroperitoneal bleeding. Patients with mild common bleeding disorder with an incidence of (>5%) and moderate (1% to 5%) disease usually up to 1% in some populations. There are three have bleeding only with injury or surgery. subtypes of VWD, the most severe and uncom- Patients may have increased bleeding with levels mon being type 3. In this form, vWF in plasma above 25%, but these deficiencies are hard to and platelets is markedly reduced or absent, detect as the aPTT will be normal. thereby reducing factor VIII activity to 1% to Treatment for hemophilia A involves infusion 10% of normal. Patients can present with spon- of recombinant factor VIII concentrates of taneous or severe bleeding. Inheritance is auto- which several are commercially available, the somal recessive. Type 1 is the most common amount depending on the deficiency present. type, representing around 70% of cases. vWF is This includes a loading dose and then a main- reduced to the range of 20% to 50% with a con- tenance dose for the appropriate period comitant reduction of factor VIII activity. The depending on the location of the bleed if spon- structure of vWF is generally normal in this taneous or perioperative. For milder hemophilia type, and inheritance is autosomal dominant. or cases of mild hemorrhage, or if factor VIII Patients usually present with mild to moderate 44

VASCULAR SURGERY bleeding diatheses, and the levels of vWF do not ents with abnormal bruising, soft tissue hemor- necessarily correlate with clinical symptoms. rhage, and epistaxis. Bleeding from the umbili- This may be because some patients with type 1 cal stump at the time of birth is common. VWD have reduced levels of both plasma and Women commonly have abnormally heavy platelet vWF, whereas some just have reduced menstrual bleeding and postpartum bleeding. plasma levels. Most cases present in adulthood. Fresh frozen Type 2 VWD is divided into further subtypes plasma is the mainstay of treatment. 2A, 2B, 2M, and 2N based on the site of the Factor VII deficiency is inherited as an auto- genetic mutation. Type 2A is the most common somal-recessive disorder and affects males and and accounts for around 10% of all vWF females equally with an incidence of about 1 in deficiency cases. Inheritance is autosomal dom- 500,000. Clinical manifestations can be similar inant. The largest multimers of vWF are absent, to those of hemophilia with severe deficiencies and this leads to a lack of platelet binding.Activ- (<1% level) as the factor Va/tissue factor com- ity of factor VIII, however, can be near normal plex is the key initiator of coagulation in vivo. in this subgroup. Clinical presentations in this However, about half of patients are asymp- group are therefore variable. In type 2B, patients tomatic, and levels of factor V do not correlate lack multimers in the plasma but have near- well with clinical manifestations. Interestingly, normal levels in platelets. However, these diminished or defective function of tissue patients are usually thrombocytopenic, which factor has not been documented as a cause of can be made worse with exercise, stress, preg- decreased factor VII activity. The most common nancy, or advanced age. Levels of factor VIII are presentations include easy bruising, soft tissue low to normal. Presentation is again variable hemorrhage, and menorrhagia in women. and inheritance is autosomal dominant. Type Patients with levels less than 1% of normal may 2M is very rare and has abnormal multimers as present like hemophiliacs with pathology its cause of abnormal coagulation. This has not including intracranial bleeds and hemarthroses. been well defined in terms of inheritance. Type Current treatment in the United States is with 2N is inherited as an autosomal-recessive con- FFP, although factor VII concentrates and dition and sometimes mimics mild hemophilia. recombinant factor VII are available in Europe. These patients have normal vWF multimers and Factor X deficiency is transmitted as an auto- normal vWF activity but reduced factor VIII somal-recessive trait and has an estimated inci- activity due to poor binding between vWF and dence of 1 in 500,000. Usually those with greater factor VIII. This variant should be considered than 15% of normal levels do not have severe in the differential diagnosis of factor VIII bleeding, although bleeding with major surgery deficiency, especially if the patient is female or trauma may occur. However, with more and other aspects of the pedigree support severe deficiencies, severe bleeding episodes autosomal-recessive inheritance rather than similar to those seen in hemophilia may occur, sex-linked. Von Willebrand disease may be including hemarthroses, retroperitoneal treated with desmopressin acetate [deamino- hematomas, hematuria, pseudotumors, and 8-D-arginine vasopressin (DDAVP)], which menorrhagia. Another cause of factor X probably increases vWF, tissue plasminogen deficiency is amyloidosis. In this situation, activator (tPA), and factor VIII secretion from transfusion of factor X is not helpful because of stored sources. Some of the subtypes may also its absorption by the extracellular amyloid. require factor replacement. More recent treat- Improvement does not occur unless the amyloi- ments include recombinant factor VIII/vWF dosis resolves, although splenectomy may help concentrates, which reduce risks of transmis- by debulking splenic amyloid. Treatment for sion of infection. standard factor X deficiency is with FFP or pro- Other factor deficiencies are quite rare. Factor thrombin complex concentrates. Pure factor X V deficiency is inherited as an autosomal- concentrates are not available for commercial recessive trait. It has a wide range of clinical use yet. Concentrations of 10% to 15% give manifestations but seems to have less bleed- adequate hemostasis. Overtransfusion can lead ing associated with it than hemophilia A. Severe to thromboembolic events and disseminated factor V deficiency (levels <1% of normal) pres- intravascular coagulation (DIC). 45

BLEEDING AND CLOTTING DISORDERS

Factor XI deficiency occurs mostly in control may be helpful with menorrhagia, and Ashkenazi Jews with a gene frequency in this DDAVP may be useful for prophylaxis prior to population of 4.3%. Bleeding usually occurs procedures. with levels £20% of normal and usually only Deficiencies of platelet collagen receptors after major trauma or surgery. Rarely, there is also exist but do not cause significant bleeding, spontaneous bleeding as seen with hemophilia, although they may prolong bleeding time. although soft tissue hemorrhage, epistaxis, and Disorders of platelet aggregation include a bleeding after dental extraction and with major deficiency of IIb/IIIa, known as Glanzmann’s surgical procedures may occur. Menorrhagia thrombasthenia, characterized by a prolonged may occur in females. Bleeding risk is signifi- bleeding time and abnormal clot retraction. It is cantly increased in patients taking aspirin. inherited as an autosomal-recessive trait in Treatment when necessary is with FFP and with clusters of disease. It presents with mucocuta- cryoprecipitate-poor plasma. Factor XI concen- neous bleeding in the neonatal period or in trates are available. infancy and occasionally as bleeding following circumcision. Epistaxis and purpura are the Fibrinogen Abnormalities most common presentation. Severe bleeding with menses may be encountered. If it is unrec- The dysfibrinogenemia are mostly inheritable ognized, significant bleeding with surgery or abnormalities of fibrinogen structure and func- trauma will occur if the patient is not transfused tion. Clinically, many patients are asymptomatic with normal platelets. Platelet counts and but some present with either bleeding or a smears are normal, but bleeding times are very thromboembolic event or both. There are mul- prolonged. Platelet aggregation is absent in tiple different abnormalities too diverse to dis- normal testing except with epinephrine, where cuss in detail in this chapter because they have it is weak. Platelet secretion is normal with variable inheritance, affect different portions of strong agonists like thrombin but is absent with the molecule, and have different manifestations. weak stimulators like epinephrine and adeno- Suffice it to say they should be considered in sine diphosphate (ADP). Clot retraction is patients with a history of bleeding and abnor- either absent or reduced. Treatment is under- mal coagulation testing. Inheritable afibrino- taken with platelet transfusion if bleeding is genemias and hypofibrinogenemias also exist. present. Leukocyte-depleted platelets may Patients present with bleeding episodes in the reduce risks with future transfusions.Hormonal afibrinogenemias and with hypofibrinogene- therapy is useful with menorrhagia. Regular mias with levels above 50mg/dL. Afibrinogene- dental care is important to reduce the risk of mias are inherited as an autosomal-recessive gingival bleeding but Amicar (e-aminocaproic trait but hypofibrinogenemias are less pre- acid) may be valuable in helping to control dictable. Bleeding complications when they bleeding after dental extractions. occur can be severe, with a high incidence of Disorders of platelet secretion are related to bleeding in the neonatal period. This may result deficiencies in one or more of the four types in death in about one third of patients with of platelet granules or to abnormalities in the severe hypo- and afibrinogenemias. secretory mechanism. Platelets have four types of granules: Platelet Disorders 1. Dense or d granules containing ADP, Bernard-Soulier syndrome (glycoprotein Ib-IX adenosine triphosphate (ATP), calcium, deficiency) is a disorder of platelet adhesion and serotonin, and pyrophosphates is a relatively rare cause of bleeding. It is char- 2. a-granules containing a variety of pro- acterized by a prolonged bleeding time, large teins, some of which are obtained from platelets, and thrombocytopenia due to an the plasma and others synthesized by inability to adhere to vWF in the subendothelial megakaryocytes; these include fibrinogen, matrix. It presents in infancy or childhood with vWF, albumin, factor V, immunoglobulin epistaxis, ecchymosis, and bleeding gums. Treat- G (IgG), fibronectin, and proteinase ment is with platelet transfusion. Hormonal inhibitors from the plasma and platelet 46

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factor-4, b-thromboglobulin, platelet- deficiency of a-granules. The content of lysoso- derived growth factor, and throm- mal hydrolase is normal, but thrombin-induced bospondin from megakaryocytes acid hydrolase secretion is impaired, which can 3. Lysosomes containing acid hydrolase only be corrected with ADP. Patients present 4. Microperoxisomes containing peroxidase with mild to moderate bleeding. Platelet counts activity are usually normal, but bleeding times are prolonged. The quantity of thromboxane B2, Secretory dysfunction usually results in mild a metabolite of thromboxane A1, is reduced. to moderate bleeding manifested by easy bruis- Secondary aggregation induced by ADP and ing, menorrhagia, and excessive postoperative epinephrine is reduced. Collagen-induced or peripartum bleeding. Testing reveals a pro- aggregation is abnormal at low concentrations longed bleeding time, a decreased second wave of collagen but is normal with high concentra- of aggregation with ADP and epinephrine tions. Therapy requires transfusions of normal stimulation, and decreased aggregation with platelets if there is massive bleeding. Otherwise, collagen. Secretory dysfunction should be dif- DDAVP is the initial treatment and cryoprecip- ferentiated from acquired disorders with acetyl- itate can also be used. In one study, pred- salicylic acid (ASA) use, uremia, and multiple nisolone seemed to reduce bleeding in patients myeloma, and from VWD. with inherited platelet disorders but not in Gray platelet syndrome is an a-granule patients with thrombasthenia or ASA use. deficiency. Platelets occur without these gran- Platelet function in patients with inherited ules but with vacuoles and small a-granule pre- disorders of platelet secretion resembles that of cursors containing material that stain positive patients receiving platelet function inhibitors for vWF and fibrinogen. Additionally, the vac- like ASA. These disorders are a heterogeneous uoles and these precursors contain P-selectin collection of abnormalities of secretion- and GIIb-IIIa. These factors indicate the pres- response adhesion. In families where these dis- ence of a-granules,but the normal proteins they orders have been noted, the pattern appears to contain cannot be packaged. Other granules be autosomal dominant. A prolonged bleeding are present in normal quantity. Patients have time and marked impairment of aggregation a history of mild to moderate mucocutaneous and secretion in response to ADP, epinephrine, bleeding. They have prolonged bleeding times and low concentrations of collagen occur. with moderate thrombocytopenia (60,000 to Stronger agonists like high levels of collagen, 100,000), reticular fibrosis of the bone marrow, however, may induce a near-normal or normal and large platelets that appear gray on Wright- response. Treatment is the same as that for stained blood smears–hence the name. Platelet patients with platelet storage disorders. aggregation studies are variable. Treatment requires transfusion of normal platelets and at Vascular Defects least one patient responded to DDAVP. The Quebec platelet disorder is extremely rare and Inheritable conditions that lead to defects in the again involves a-granules that appear grossly vascular bed include Marfan’s syndrome and normal but are deficient in many of the proteins Osler-Weber-Rendu disease. These may increase normally seen including factor V, fibrinogen, bleeding through mechanisms that are not vWF, and fibronectin. Patients present similarly entirely clear. to the gray platelet syndrome and are treated the same way. Dense granule deficiency or d-storage pool Acquired Disorders disease is a heterogeneous group of disorders, which can be divided into deficiency states asso- of Coagulation ciated with albinism and those in otherwise normal patients. With albinism, the disease is This group of disorders includes factor related to a qualitative deficiency in these gran- inhibitors as well as acquired diseases that affect ules. In nonalbinos, the number of granules platelet and endothelial function. Factor is near normal. In some of these nonalbino inhibitory proteins can be classified as neutral- patients it is associated with a variable izing, nonneutralizing, or altering. They are 47

BLEEDING AND CLOTTING DISORDERS usually autoantibodies. The most common Hypercoagulable States factor inhibitor is factor VIII, often referred to as acquired hemophilia, but inhibitors have Like bleeding disorders, these states can be been found to thrombin and prothrombin, categorized as inherited or acquired (Table 5.6). fibrinogen, thrombin and prothrombin, fibrino- Hyperhomocystinemia, however, can be either gen, vWF, and factors V, VII, IX, X, and XI as inherited or acquired. Indications for throm- well (Fig. 5.1). These are seen in response bophilia screening have already been outlined to inflammatory diseases such as rheumatoid and the components of such a screen are arthritis and other autoimmune diseases like referred to in Table 5.3. For most of the hyper- systemic lupus erythematosus (SLE) and coagulable states, treatment involves the use of Sjögren’s syndrome and even inflammatory LMWH or unfractionated heparin with conver- bowel syndrome. They also appear during preg- sion to oral warfarin. Often, if the patient has nancy and the puerperium, as well as with already had a thrombotic episode, anticoagula- various tumors. They may be associated with a tion is undertaken for life. variety of medications including aminoglyco- sides, penicillins, valorous acid, etc. They are also seen with cirrhosis and major surgery. Interestingly, factors V and X and thrombin Table 5.6. Differential diagnosis for hypercoagulable states inhibitors have been seen following the use of topical thrombin and fibrin glue, usually after Inherited (primary) multiple exposures. Not only can this lead to Protein C and S deficiencies Antithrombin III deficiency perioperative bleeding, but also inhibitors of Factor V Leiden mutation leading to activated factor X can interfere with monitoring of low- protein C resistance molecular-weight heparin (LMWH) anticoagu- Prothrombin 20210A gene mutation lation with the antifactor Xa assay. Heparin cofactor II deficiency and other heparin Factor inhibitors may lead to increased bleed- binding proteins ing and, rarely, spontaneous bleeding. Most Cystathionine synthase deficiency conditions are initially detected as a prolonga- (hyperhomocystinemia) tion of one or more of the coagulation screen- Dysfibrinogenemia ing tests—PT/INR/aPTT—or thrombin time. Dys- and hypoplasminogenemia To differentiate between the different types of Acquired (secondary) inhibitors, a clotting study should be done on a Cancer 1:1 mixture of the patient’s plasma with normal Pregnancy plasma. A lack of correction of clotting time Oral contraceptives and other hormone replacement indicates a neutralizing antibody. Vigilance in therapy (HRT) testing is essential because at body temperature Myeloproliferative disorders Hyperlipidemia some studies initially correct and then return to Diabetes mellitus a prolonged state after an hour. This is particu- larly true of factor V and VIII inhibitors. Antiphospholipid syndrome (lupus anticoagulant, If the mixing study corrects, this suggests the anticardiolipin antibodies) presence of a nonneutralizing antibody that Postoperative states/trauma may facilitate clearance of the clotting factor Immobilization from circulation. The antibody should be Nephrotic syndrome isolated to differentiate its presence from a Congestive heart failure deficiency of the factor. Increased levels of factor VII and fibrinogen Treatment of bleeding includes infusion of Obesity Heparin thrombocytopenia factors to levels that overwhelm the antibodies Anticancer drugs (bleomycin, vinca alkaloids, and return the coagulation profile to normal. mitomycin, etc.) Long-term treatment includes immunosup- Paroxysmal nocturnal hemoglobinuria pression with steroids or other agents and Age plasmapheresis with immunoabsorption with Undetermined Ig-Therasorb. The latter can be used in con- Elevated factor XI levels and VIII levels junction with transfusion. 48

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Inherited Protein C and S deficiencies have relatively the same incidence. They both result from Inherited hypercoagulable states account for 5% numerous different mutations. A heterozygote to 15% of patients with venous thromboem- pattern is much more frequent as homozygotes bolism (VTE). The most common appear to be present soon after birth with purpura fulminans the factor V Leiden mutation followed by the or massive . Protein C has prothrombin G20210A mutation of the pro- type I and type II deficiencies. Type I deficien- thrombin gene among the white population, but cies are those mutations causing a decrease in these are rare in Asians and Africans. Table 5.7 levels and in activity; most of these are missense shows the overall incidence of the various inher- mutations. Type II deficiencies are those in ited hypercoagulable states. These are estimates which levels are normal but activity is affected; from several studies and vary with ethnic back- most of these are point mutations. Patients with ground and location. protein C deficiency tend to present with VTE Factor V Leiden, also known as activated pro- and fetal loss and rarely with arterial thrombo- tein C resistance (APCR), results from a point sis. Protein S deficiency is harder to define. mutation in the factor V gene, leading to a loss Many studies have shown the coexistence of of protein C cleavage sites (Ouriel et al., 1996). protein S deficiency with APCR in as high as The consequence of this is impaired activation 40% of the patient population studied. This of protein C. The most common presentations makes it hard to determine which is more are VTE and fetal loss. It usually does not result important. However, there are more numerous in arterial thrombosis unless other risk factors reports of arterial thrombosis with protein S are also present, for example smoking. deficiency, including stokes, compared to Homozygotes have an 80-fold increased risk of protein C deficiency. Many conditions may DVT, and heterozygotes have much less. Many result in lowered levels of these proteins, partic- patients with factor V Leiden remain asympto- ularly protein S (for instance in liver disease, matic, and about 60% of those who present with nephrotic syndrome, pregnancy, sepsis, etc.) thrombosis have another risk factor such as use and some medications like HRT may have the of oral contraceptives (OCs) or hormone same effect. Therefore, measurement of levels of replacement therapy (HRT). The overall risk of protein S may need to be repeated to ensure VTE is 3% to 7%. accuracy as well as to allow checking for specific The prothrombin 20210A gene mutation genetic defects. Overall, as many as 50% of appears in 2.3% of healthy control patients. The heterozygotes for protein C and S deficiencies incidence is twice as high in southern Euro- develop VTE up to the age of 50 years. peans compared to northern Europeans and is Antithrombin III (AT III) deficiency occurs as rare in Asians and Africans. The mutation an autosomal-dominant disorder and in 1/5000 increases prothrombin levels and activity. The healthy blood donors. It may also have type I relative risk of clotting is two to three times that and type II deficiencies. The type I deficiencies of normal individuals. are caused by both gene segment mutations as well as point mutations, whereas the type II deficiencies are caused mostly by point muta- tions. Most patients are heterozygotes, Table 5.7. Incidence of inherited disorders as homozygous deficiency is probably incom- Disorder Incidence patible with life unless it is a type II deficiency Factor V Leiden (activated protein 25% of the heparin-binding site. All types are at C resistance) increased risk of VTE, with as many as 80% of Sticky platelet syndrome 14% heterozygotes by age 50 having an episode of Protein C deficiency 10% VTE. Like protein C and S, AT III deficiency can Protein S deficiency 10% be acquired in association with the medical con- Prothrombin G20210A 5–10% ditions described above. Increased homocysteine 5–10% Hyperhomocystinemia and homocystinuria Dysfibrinogenemia 1.5% have both been described as associated with Antithrombin III <1% (1/250–500) Dys- or hypoplasminogenemia 1–3% VTE and arterial thrombotic events (Nehler et al., 1997). Homocysteine is an intermediate of 49

BLEEDING AND CLOTTING DISORDERS methionine metabolism. Elevated levels arise be difficult to monitor with a baseline elevated from both genetic defects affecting the transsul- aPTT. Acquired dysfibrinogenemia is seen with furation or remethylation pathways as well as liver disease, multiple myeloma, Waldenström’s with folate, B6 and B12 deficiency, renal failure, macroglobulinemia, and autoimmune diseases; hypothyroidism, increased age, and smoking. the end result of all of these conditions is altered Homozygotes for cystathionine b-synthase polymerization or delayed fibrinopeptide deficiency and methylene-tetrahydrofolate re- release. ductase may have severe vascular disease and Dys- or hypoplasminogenemias occur even appear even in childhood. As many as 60% have more rarely. These are usually autosomal dom- thromboembolic events before age 40 and 50% inant. Patients usually present in their late teens, by age 29. Heterozygotes have a high incidence most commonly with VTE. Routine tests are of premature arterial occlusive disease, which normal. There are also rare congenital deficien- may represent as much as 1/70 of the normal cies of tPA and congenital increases of plas- population. However, the most common cause is minogen activator inhibitor (PAI). These dietary folate and B6 and B12 deficiencies, which disorders are more commonly acquired with account for around two thirds of the cases diabetes, inflammatory bowel disease, and coro- of hyperhomocystinemia. Measuring fasting nary atherosclerosis. homocysteine plasma levels establishes the Factor XII is involved with plasmin genera- diagnosis. The mechanism of thrombosis is tion. There is an autosomal-dominant genetic thought to involve several mechanisms includ- deficiency, which is quite rare but results in both ing induction of endothelial cell tissue factor VTE and arterial thrombosis. About 8% of activity, inhibition of thrombomodulin, deficient patients have thrombotic episodes. An decreased AT III activity, decreased protein C elevated PTT is present, but it corrects with the activation, increased factor V activity, and addition of normal plasma. Treatment is with increased affinity of lipoprotein (a) and fibrin. LMWH and then warfarin. Standard unfrac- Dietary supplements with B6,B12, and folate help tionated heparin again is difficult to monitor lower the homocysteine levels, but unfortu- with baseline elevated PTT. nately this may not reduce the risk of thrombo- Heparin factor II and other heparin-binding sis and therefore anticoagulation may also be molecules are found to have deficiencies; how- indicated. ever, the association with thrombotic events is The dysfibrinogenemias can cause thrombo- weak. The same is true for thrombomodulin sis as well as bleeding in around 20% of patients. defects. The conversion of fibrinogen to fibrin consists The sticky platelet syndrome is a rare of three main steps: release of fibrinopeptides A autosomal-dominant disorder that results in and B from the alpha and beta chains to form platelets that aggregate more readily with epi- fibrin monomers, followed by polymerization of nephrine or ADP.Venous and arterial thrombo- these monomers to a visible fibrin gel, which is sis occur, and retinal vascular thrombosis then stabilized by activated factor XIII. Fibrin appears to be associated with this entity. Treat- may then be broken down via fibrinolysis path- ment is initially with low-dose aspirin. If aggre- ways. Inherited dysfibrinogenemias result from gation does not normalize, then this dose can be mutations that alter one or more of these steps. increased to 325mg daily. Clopidogrel (Plavix) They are usually autosomal dominant. One may provides an alternative potential therapy. be suspicious if there is a prolongation of the Another platelet defect is the Wein-Penzing PT and PTT. Thrombosis can occur secondary deficit. This is a deficiency of the lipoxygenase to either an abnormal fibrinogen with reduced metabolic pathway resulting in an increase in binding to thrombin and increased thrombin the cyclooxygenase pathway and therefore ele- levels, or decreased fibrinolysis. It is relatively vated thromboxane levels. Platelets are thus in a rare for this to be the sole cause of VTE (around state of increased activation. 0.8% of VTE) and is frequently associated with Other abnormalities that may be genetically precipitating risk factors such as HRT, pro- based include elevated factor XI and factor XIII longed bed rest, etc. Treatment remains anti- levels. Both these groups seem to have increased coagulation, but it is preferable initially to use risk of VTE, and the level of increased risk LMWH, as unfractionated heparin activity can appears to be proportional to the increase in the 50

VASCULAR SURGERY levels of these factors. Hormone replacement and may have hemolytic anemia (14–23%) and therapy and pregnancy are also implicated in livedo reticularis (11–22%). Renal involvement raised levels of these factors. Patients on HRT or may occur, and when it does it usually results in OC and with elevated factor VIII levels have a hypertension. 10-fold increased risk of VTE compared to those Catastrophic APA syndrome is acute, and without these risk factors. multiple simultaneous vascular thrombotic events can occur throughout the body. Small Acquired vessels of multiple organs are often affected.The syndrome may result in death. In 78% of these The most common cause in this group of con- patients the kidneys are involved, followed by ditions is the antiphospholipid antibody (APA) the lungs in 66%, the central nervous system in syndrome (Fligelstone et al., 1995). These anti- 56%, the heart in 50%, and the skin in 50%. Dis- bodies bind to plasma proteins that have a high seminated intravascular coagulation is a com- affinity for phospholipid surfaces. The most ponent of this event in 25% of patients. The common of these proteins are the lupus antico- mortality rate is 50%, usually due to multisys- agulant (LA), anticardiolipin (ACL) antibodies, tem organ failure. The optimal treatment is and anti–b2-glycoprotein-1 antibodies (B2G). not well defined but includes, in various com- These are usually acquired. Lupus anticoagulant binations of anticoagulation, steroids and either can be suspected if there is an elevated PTT,and plasmapheresis or intravenous immune globu- ACL and B2G are detected only by immunoas- lin. The condition can be precipitated by says. These conditions can be primary, that is, surgery, infection, withdrawal of anticoagula- not associated with other autoimmune condi- tion therapy, and drugs, including oral tions. They can present with VTE or arterial contraceptives. thrombosis as well as fetal demise. Antiphos- Heparin-induced thrombocytopenia (HIT) pholipid antibodies may be associated with also warrants some discussion. The entity was infections, cancer, and even certain drugs and first described by Towne in 1979 as the white , but these are usually IgM as clot syndrome and occurs in 1% to 30% of opposed to IgG antibodies and are present in patients on heparin. Heparin-induced thrombo- low levels. They do not seem to be associated cytopenia is diagnosed by one or more HIT- with thrombotic events. associated clinical events, such as thrombosis of The overall incidence is 1% to 5% of the a graft, and the presence of heparin antibodies. normal population. The incidence increases Various tests (Table 5.8) are now available to with age and coexisting chronic disease. The help in making the diagnosis (Warkentin and incidence in patients with SLE is 12% to 30% for Greinacher, 2004). The problem is that the onset ACL and 15% to 34% for LA. The risk of throm- of HIT is often delayed or seen after multiple bosis in patients found to have these autoanti- exposures to heparin, where the first few expo- bodies is unclear but seems to be increased in sures resulted in minimal or no decrease in those with a history of previous thrombosis, platelets. Additionally, the delayed onset may with LA and with increased IgG ACL—each of be seen only after the offending heparin has which increases the risk of thrombosis fivefold. been removed. The initial exposure can be The persistent presence of APA also increases as inconsequential as heparin lock flushes to the risk of thrombosis. These patients have a maintain the patency of intravenous lines or high proportion of pregnancy losses as well as standard subcutaneous heparin prophylaxis. an increased incidence of premature births. Treatment includes stopping the heparin. These patients are best treated with ASA plus Coumadin alone is not a good treatment due to heparin to achieve live births. the hypercoagulable period before anticoagula- Interestingly, not all arterial episodes of tion is achieved, leading to potential skin necro- ischemia or infarction are due to primary sis. Additional therapy is switching to hirudin thrombosis. Up to 63% of patients with APA (Refludan), argatroban (Novastartan), or dana- syndrome have coexisting valve abnormalities parnol (Orgaran). Additionally, some of the on echocardiography and 4% have vegetations GIIb-IIIa inhibitors have been successfully of the mitral or aortic valve. These patients may employed in this situation. Newer agents are also be thrombocytopenic (as many as 40–50%) under investigation including a recently Food 51

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Table 5.8. Testing for heparin-induced thrombocytopenia Sensitivity Specificity Positive Negative (%) (%) predictive value predictive value (%) (%) PF4 + heparin coated plate: anti IgG, IgA, 97 86 93 91 and IgM Serotonin release 88 100 100 81 Platelet aggregation 91 77 89 81

Ig, immunoglobulin; PF4, platelet factor 4. and Drug Administration (FDA)-approved oral appropriate anticoagulation with the exception anti–factor Xa agent. of catastrophic amyotrophic lateral sclerosis Most malignancies can be associated with a (ALS). The cumulative risks of different inher- higher incidence of thromboembolic events, in ited and acquired thrombophilic factors have particular, adenocarcinoma and myeloprolifer- appreciable significance. Individual personal- ative disorders. ized risk profiles for thrombotic events may have a role to play for patients in the future. An awareness of the broad extent of these condi- tions helps vascular surgeons provide optimal Conclusion management for their patients. Bleeding and clotting disorders are encountered sufficiently frequently in vascular surgical prac- References tice to encourage an awareness of the range of disorders and of the different available thera- Donaldson MC, Weinberg DS, Belkin M, Whittemore AD, peutic modalities. A high index of suspicion, a Mannick JA. (1990) J Vasc Surg 11:825–31. comprehensive medical history, and judicious Fligelstone LJ, Cachia PG, Ralis H, et al. (1995) Eur J Vasc employment of investigations help guide the Endovasc Surg 9:277–83. experienced clinician to a correct diagnosis.The Nehler MR, Taylor LM Jr, Porter JM. (1997) Cardiovasc Surg 5:559–67. bleeding disorders are varied, and each requires Ouriel K, Green RM, DeWeese JA, Cimino C. (1996) J Vasc specific management. The majority of throm- Surg 23:46–51, discussion 51–2. bophilic tendencies may simply be treated with Warkentin TE, Greinacher A. (2004) Chest 126:311S–337S. 6 Medical Management of Peripheral Arterial Disease Jill J.F. Belch and Andrew H. Muir

Atherosclerosis Thus we now recognize that atherosclerosis is a systemic disorder affecting the entire vascular Peripheral arterial disease (PAD) is a marker tree. Extracranial carotid disease can lead to for multisystem vascular disease. Workers in stroke, CAD to myocardial ischemia/infarction, this field recognized this over 150 years ago, renovascular disease to hypertension, and aor- noting the similarity between claudication toiliac and infrainguinal arterial disease to IC or symptoms and angina. Since then, published limb-threatening ischemia. The mainstay of the work has supported this view, but the com- medical management of vascular disease is to monality of the link between PAD and coronary understand that it is a systemic disorder and artery disease (CAD) has only now been fully must be managed as such. Thus the medical recognized. Myocardial infarction (MI) and management of PAD is a complex area that stroke are the biggest risks to life and health includes strategies for vascular risk reduction, for the PAD patient rather than amputation lifestyle advice, and direct pharmacotherapy or critical limb ischemia (CLI). The natural for the vascular disease. Its implementation history of intermittent claudication (IC), the requires a multidisciplinary team, which in- usual symptom of lower limb atherosclerosis, is cludes not only vascular physicians, vascular often benign. Most patients improve or their surgeons, and interventional radiologists but disease remains stable. Less than 5% of patients also many of the professions allied to medicine require amputation. In contrast, however, the and, importantly, our primary care colleagues. death rate in these patients is three to four Areas of focus for such a vascular team are out- times higher than in patients of similar age lined in Table 6.1. without IC (Fig. 6.1). This mortality occurs due to atherosclerosis at other sites within the body. Only one quarter of the mortality of these pa- tients is from nonvascular events. One half die Vascular Risk Factor from CAD, 15% as a result of stroke, and 10% Modification in Peripheral from vascular pathology within the abdomen such as ruptured aortic aneurysm. The associa- Arterial Disease tion between PAD and generalized vascular mortality is so strong that even in asymptomatic The medical management of vascular disease PAD [detected by a decrease in the ankle– must focus on modification of the following brachial index (ABI)] the patient’s relative risk specific risk factors that promote the progres- of a cardiac or cerebrovascular event is very sion of the disease: (1) platelet aggregation, (2) much higher. smoking, (3) obesity, (4) diabetes, (5) dyslipi-

53 54

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products are vasoactive, and these include thromboxane A2 and serotonin, both potent vasoconstrictors.

Antiplatelet Agents Current interest in antiplatelet agents relates to their use as prophylactic treatments against arterial events in other beds and atherosclerosis disease progression.

Figure 6.1. Mortality of peripheral arterial disease (PAD).The 5- year mortality of PAD is relatively equivalent to numerous Aspirin in Peripheral Arterial Disease cancers (prostate, breast, colorectal, and lung). Aspirin is the most commonly used antiplatelet agent, reflecting the fact that it is currently the cheapest agent available and one of the best studied agents in clinical trials. Its action demia, (6) hypertension, (7) sedentary lifestyle, includes the irreversible inhibition of the cyclo- and (8) type A personality or stress. The literature suggests that cigarette smok- ing, hypertension, dyslipidemia, and diabetes mellitus are important factors in the develop- Table 6.1. Medical strategies for the management of ment of PAD,and these will be addressed in turn peripheral arterial disease (Table 6.2). A key risk factor for PAD is platelet Address vascular risk aggregation along with other hemorheological Antiplatelet therapy factors such as increased plasma fibrinogen and Cigarette smoking decreased fibrinolysis. Currently an area of Dyslipidemia interest that is being explored is that of the con- Hypertension tribution of inflammation to PAD. The high Diabetes white blood count (WBC) contributes vascular Obesity Thrombophilia risk to the patient with PAD (Belch et al., 1999) Specific therapy for intermittent claudication as does increased oxidative stress. Of the above, Exercise however, platelet activation and release in the ?Drug therapy patient with PAD has been well documented Vasculitides as a cause of symptoms and has led to the evidence-based use of Connective tissue disease antiplatelet agents in PAD. Raynaud’s phenomenon Vasculitis Antiphospholipid syndrome Embolism as a cause of symptoms Detect and treat arrhythmia and/or cardiac Platelet Aggregation thrombus Exclude aortic aneurism Platelet aggregation is increased in patients with Chronic limb symptoms PAD, and the role of such aggregates in arterial Control edema thrombosis has been well documented. Platelet Control infection release products also contribute to the underly- Improve cardiac output ing pathology. b-Thromboglobulin is one such Acute critical limb ischemia (CLI) product that, once released from platelets, con- Thrombolysis tributes to neutrophil activation. Platelet factor Anticoagulation 4 neutralizes heparin, and platelet-derived (DVT) Prophylaxis growth factor stimulates proliferation of vas- Treatment cular smooth muscle cells. Some of the release 55

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Table 6.2. Risk factors for intermittent claudication Risk Management Other cardiovascular events, e.g., MI, stroke • Antiplatelet agent Aspirin, clopidogrel, dipyridamole Smoking • Cessation program Counseling Nicotine replacement, e.g., patch, gum, spray Dyslipidemia • Lipid-lowering therapy Diet ± drug Target: LDL cholesterol <3.0mmol/L HDL ≥20% Triglycerides <1.8mmol/L Hypertension • Antihypertensive therapy Select: ACE inhibitor Calcium channel blockade Diuretic Avoid beta-blockade (unless vasodilatory) Target BP <140/85 (in diabetes <140/80) (Note: 25% will have renal artery stenosis; watch renal function) Diabetes • Check for hyperglycemia Fasting glucose ≥ 7.8mmol/L If borderline glucose (random or fasting), glucose tolerance test with fasting and 2-hour sample 2-hour sample: <7.8mmol/L normal ≥7.8–11.0 impaired ≥11.1 diabetic Obesity • Check for obesity Body mass index ≥30 Low-fat, high-fiber diet, healthy eating Calorie control Thrombophilia • Consider referral for thrombophilia screen (inherited or acquired) Suspect if: Young (<50 years of age) Connective tissue disease, e.g., SLE Additional history of unexplained venous thrombosis Previous failed vascular reconstruction Strong family history of thrombosis

SLE, systemic lupus erythematosus.

oxygenase enzyme.Platelet aggregation is there- studies are currently under way. In both these fore decreased. studies aspirin is being evaluated in subjects with decreased ABIs but who are currently Primary Prevention of Peripheral asymptomatic in terms of PAD. One of the Arterial Disease studies is a population-based study and the other is a study of patients with diabetes melli- As yet there is no published evidence to suggest tus. This latter study, Prevention of Progression that aspirin prevents the primary development of Arterial Disease in Diabetes (POPADAD) has of PAD in a normal population. Such a study recruited 1250 patients with decreased ABI, and would require a huge population base. One aspirin versus placebo is one of the arms of this method of decreasing the numbers required study, which has a composite end point of vas- to be studied would be to increase the risk of cular events and mortality. This is a Scotland- the population enrolled in the trial. Two such wide study and results should be available soon. 56

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Primary Prevention of Vascular Surgery patients with PAD suggested greater benefit to these patients from clopidogrel than in other Aspirin has been evaluated in the primary pre- patient populations. An event rate of 3.1 per vention of requirement for peripheral vascular annum compared to 4.86 per annum in the surgery in the U.S. Physicians’ Health Study. In aspirin group gave a relative risk reduction of the aspirin group the risk of undergoing surgery = 23.8% [95% confidence interval (CI) 8.9–36.2] in for PAD was decreased by 46% (p .03). Aspirin favor of clopidogrel (p = .0028). A reasonable did not, however, affect the likelihood of devel- strategy,therefore,in the 30% of all patients who oping claudication de novo during the trial developed gastrointestinal (GI) side effects from period. aspirin is to combine the aspirin initially with the gastric protectant, and if this fails, change to clopidogrel. This drug provides an improve- Aspirin in the Prevention of Coronary and ment to our therapeutic resources in terms of Cerebrovascular Events in Peripheral tolerated antiplatelet drugs. Arterial Disease The Antiplatelet Trialists Collaboration, now Dipyridamole called the Antithrombotic Trialists Collabora- tion, has provided the most convincing data Dipyridamole is an antiplatelet agent that is supporting the use of aspirin in PAD. In a meta- thought to work through a number of mecha- analysis of 174 randomized trials of various nisms including increasing the effect of prosta- antiplatelet agents (mainly aspirin), a decrease cyclin (PGI2), and inhibiting the cellular uptake in nonfatal MI, nonfatal stroke, and vascular of adenosine and platelet phosphodiesterase, death in patients treated by antiplatelet therapy thus enhancing further the effects of PGI2.The was detected. Subgroup analysis of high-risk use of dipyridamole itself or in combination patients was carried out. This included patients with aspirin has produced much controversy. with PAD, and the percentage of risk reduction Three decades ago there was excitement about versus placebo were as follows: 46% for non- the potential benefits of combining aspirin and fatal stroke, 32% for the risk of vascular disease, dipyridamole, but by the 1980s aspirin alone MI, or stroke, and for nonfatal MI, and 20% for became the favorite choice. Evidence that the death from vascular causes. The most frequently combination treatment is effective has been used dosages of aspirin were between 75 and forthcoming in one of the large stroke studies 325mg per day. Subsequent work has confirmed (Diener et al., 1996), and certainly the combina- that there is no evidence that the higher doses tion has been found to be more effective in the are more effective than the lower ones (i.e., prevention of peripheral graft failure in one >75mg per day), although bleeding risk is dose study. It is our current practice to use both dependent. aspirin and dipyridamole in patients with stroke or transient ischemic attack (TIA) but to use aspirin or clopidogrel alone in patients with Clopidogrel PAD. In stable PAD we usually reserve dipyri- damole for the aspirin-intolerant patient, al- Clopidogrel irreversibly blocks the binding of though clopidogrel is now our first choice for adenosine diphosphate (ADP) and thus its this indication. activation of platelets. The Clopidogrel versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) study evaluated the risk of vascular Conclusion death, MI, and stroke in patients with vascular disease receiving either clopidogrel or aspirin. There is convincing evidence that antiplatelet Clopidogrel reduced the event rate by 5.32% per agents such as aspirin and clopidogrel are effec- annum versus 5.83% with aspirin (p = .043). tive in preventing cardiac and stroke events in These figures reflect a relative rate reduction of patients with PAD. It is therefore recommended 8.7% in favor of clopidogrel. No major differ- that an antiplatelet drug should be prescribed ences in safety issues between the two drugs for these patients unless there is a clear con- was detected. An ad hoc subgroup analysis in traindication to such therapy. 57

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Smoking PAD patients stop smoking. Improved cessation rates, however, can be achieved through increas- Both the risk of PAD and its progression is ing support through counseling or the provision significantly increased by the smoking of of judicious nicotine replacement therapy. tobacco. Patients who smoke have a significantly There are numerous smoking cessation pro- increased risk of atherosclerosis and of another grams and pharmacological aids available for tobacco-related peripheral vascular disease, patients. Smoking cessation aids such as nico- thromboangiitis obliterans (Buerger’s disease). tine patches and nicotine gum work best in the Of all the risk factors discussed here, the use of setting of a specific smoking cessation program. tobacco contributes most to the development of Nicotine chewing gum was the first type of nico- PAD. A number of studies have linked tobacco tine replacement therapy (NRT) to become smoking and the development of IC. In the widely available, with subsequent development Framingham study smokers were twice as likely of transdermal patches, intranasal sprays, and to develop IC. The progression to critical limb inhalers. These latter forms of therapy may ischemia is more likely in smokers, as is ampu- attenuate some problems with the gum such as tation. The effect of cigarette smoking on vas- transfer of dependency. A meta-analysis of 53 cular graft patency is well recognized. In one trials of NRT (42 gum,nine patch,one spray,and study the 5-year cumulative patency rate for one inhaler) (Silagy et al., 1994) showed that grafts was between 80% and 90% for nonsmok- NRT increased the odds ratio for abstinence: ers, with the corresponding patency rates being 1.61 for gum, 2.07 for patch, 2.92 for nasal spray, between 30% and 45% for those who smoked and 3.05 for inhaled nicotine. Nicotine replace- more than five cigarettes a day. ment therapy can be an effective aid to smok- Smoking cessation slows the progression ing cessation. However, it is contraindicated in of peripheral arterial disease to critical limb acute MI, unstable angina, and in patients with ischemia and lowers the risk of MI and death. cardiac arrhythmias. Thus, it is important to The nicotine present in tobacco products is work with patients to engage them in a specific highly addictive; hence, smoking cessation is program. a very difficult process for patients, and the Finally, because the recidivism rate is high, it recidivism rate is high. The key feature in the is important to be encouraging at follow-up approach to smoking cessation is for the physi- visits once a patient has stopped smoking. cian to positively encourage the patient to stop Physician encouragement throughout the smoking. Without a clear message from the process of smoking cessation and remaining physician that smoking is an underlying cause tobacco free is essential. of atherosclerosis and promotes the progression of atherosclerosis, patients will continue to smoke. Thus, the first step is to clearly tell Conclusion patients that it is medically indicated that they Smoking causes PAD. Its cessation is difficult stop smoking. without support. Nicotine replacement and Although the majority of smokers would like other aids to cessation should be made available to quit, 90% are physically addicted to nicotine to PAD patients. and at least 75% have tried to stop smoking more than once. Three quarters of those who do stop restart within 3 months, and it is clear Obesity that the issue of nicotine dependence must be addressed. During the early stages of quitting, Obesity has reached epidemic proportions in smokers experience both behavioral and physi- developed countries. Obesity contributes to cal withdrawal symptoms. It is crucial to explain numerous medical problems including athero- to the patient that the chemical withdrawal sclerosis. It is important to recognize if patients symptoms are short lived as they can exert are overweight and to obtain the appropri- strong pressure on the smoker’s will to stop. ate dietary consultation to assist patients with This also underlines the fact that we must weight loss. Most weight-loss programs are provide support to these patients. After re- not successful unless they include lifestyle ceiving only medical advice, only 5% of modification and a specific exercise program. 58

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Conclusion is consistently underdiagnosed in PAD and this can have serious consequences. Obesity contributes to the development of type Diabetes contributes to atherosclerosis, and 2 diabetes, hypertension, and dyslipidemia, all studies have indicated that tight glucose control known to be associated with PAD. Appropriate limits the progression of end-organ damage due weight-reduction programs should be recom- to diabetes, including atherosclerosis. Physi- mended. It should be noted that smoking cessa- cians involved in the care of diabetic patients tion promotes weight gain, and that in a patient with atherosclerosis must work closely, as a with PAD smoking cessation is the most impor- team, with other caregivers involved in the man- tant element in risk reduction. A level of weight agement of diabetes to ensure tight glucose gain therefore should be tolerated, at least in the control. short term. Conclusion Diabetes Mellitus It should be remembered that all risk factors Peripheral arterial disease and diabetes mellitus are synergistic in terms of vascular disease, not frequently occur together. Probably half of all merely additive, and the failure to diagnose patients with diabetes mellitus have evidence of underlying diabetes in a PAD patient who PAD 10 to 15 years after diabetes onset. Fur- smokes will have serious consequences for that thermore, glucose intolerance correlates with patient. angiographic disease extent. Diabetic patients account for one third of below-knee amputa- Dyslipidemia tions and 50% of amputations when distal amputations are included. The pathology of the Abnormal lipid profiles are well recognized in diabetic limb is multifactorial, including contri- patients with atherosclerosis. The relationship butions from both micro- and macrovascular between cholesterol level and CAD risk is con- disease.Asymptomatic PAD occurs in 20% of all tinuous, with no obvious “safe” cut-off point. diabetic patients with no other evidence of Patients with PAD are likely to be identical. A vascular disease (POPADAD screening of 8000 number of studies investigated cholesterol in patients). Thus the occurrence of overt diabetes PAD and found it to be a significant, though and PAD is well documented. We are less expert weak, risk factor for claudication, and above the at detecting early diabetes in our patients with age of 55 years to correlate with ABI. Reduced PAD, however. Distal disease on angiography or HDL is associated with increased PAD severity,6 increased ABI (due to vessel stiffening) can lead with strong inverse relationships between HDL to the retrospective diagnosis of diabetes melli- cholesterol and PAD that persist after adjust- tus, but this still underestimates the figure. Of ment for other risk factors. Furthermore, ele- 100 consecutive patients presenting at our vas- vated serum triglyceride levels have been cular surgery clinic, 40% had abnormal glucose reported in both cross section and longitudinal tolerance tests. The majority of these patients studies. It has been suggested that the link had normal random or fasting sugars and were between increased triglyceride level in patients diagnosed only on the basis of this glucose tol- with PAD and the development of the disease erance test. Currently we do not give a glucose might be explained by the increase in low- tolerance test to all PAD patients but do use this density lipoprotein (LDL) providing the form of diagnosis for patients who have raised enhanced vascular risk. ABI in the presence of symptomatic IC, in those Despite the links between abnormal lipid in whom the distal distribution of the PAD profiles and PAD, there have been no clinical would arouse a suspicion of diabetes, and in studies with the PAD patient as primary end those with a “diabetic” lipid profile where both point. The situation has now been overtaken by cholesterol and fasting triglyceride levels are the Heart Protection Study (2002) and various elevated and high-density lipoprotein (HDL) guidelines with recommendations for lipid- levels are low. Detection of asymptomatic dia- lowering therapy if there is a >3% chance of a betes mellitus in the PAD patient is a major part vascular event per annum. Such a risk clearly of the medical management of these patients. It occurs in patients with PAD. 59

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All of the major trials in the field of lipid the Scottish Intercollegiate Guidelines Network lowering that have been reported over the (SIGN) guideline on the management of hyper- past decade have showed variously a decrease tension and the British Hypertension Society in CAD mortality, major coronary events, guidelines have given clear guidance in terms of and the need for coronary revascularization. acceptable BP levels. Therapy should be started Together the data suggest that four out of nine in all PAD patients with sustained systolic BP deaths occurring in a group of subjects with elevations recorded above 140mmHg or dias- cholesterol >5.5mmol/L will be prevented by tolic BP above 90mmHg. The optimum target treatment. blood pressure is a systolic BP of <135mmHg More recently, the Heart Protection Study and a diastolic of <85mmHg. A more stringent (HPS) demonstrated for the first time a benefit target is required for those patients with from statin therapy for prevention of vascular diabetes and this is important, as many PAD events in patients with PAD (HPS Collaborative patients have diabetes mellitus where a target Group, 2002). This largest-ever trial of choles- of £130/80mmHg is recommended. Three terol-lowering therapy enrolled more than long-term double-blind studies (Materson et al., 20,000 high-risk patients, of whom 2700 had 1993) have compared all the major classes of symptomatic PAD but no prior CAD. Treatment antihypertensive drug therapy and overall with simvastatin 40mg/day reduced major vas- showed no consistent or important differences cular events (coronary events, stroke, and revas- in terms of efficacy of BP control, side effects cularization) by 20% in patients with PAD, a from the drugs, or quality of life. It has been similar reduction to that observed in the study suggested that hypertensive patients whose BP overall. Moreover, the benefits observed in the is controlled by thiazides or beta-blockers may HPS were not influenced by baseline levels of continue to experience the excess risk of coro- blood lipids. The findings of the HPS, therefore, nary death. These two drug classes change strongly suggest that statin therapy should be glucose intolerance and lipid profiles in a dose- considered on the basis of high risk rather than dependent fashion, and it may be that the lower high cholesterol, a category into which patients doses of thiazides currently employed do not with PAD undoubtedly fall. show this effect. Although b-adrenergic antago- nist drugs have been previously reported to Conclusion enhance PAD symptoms through their vasocon- strictor effects, more recently it has been sug- Elevated cholesterol and triglycerides contri- gested that this is not so. It is of interest that the bute to the development and progression of new vasodilating beta-blockers do not even atherosclerosis. Thus, it is important to obtain a have this theoretical contraindication and might lipid profile on any patient with atherosclerosis. be used safely in patients with PAD. The use Management of dyslipidemia initially involves of angiotensin-converting enzyme inhibitors dietary change followed by specific medical in patients with PAD may confer protection management if necessary. The goal of lipid- against future atherosclerotic events. However lowering therapy is to achieve a serum LDL care must be taken in the presence of renal cholesterol concentration less than 100mg/dL artery stenosis, another common finding in or 3mmol/L and a serum triglyceride less than patients with PAD. 150mg/dL. Care must be taken when treating hyperten- The first choice for pharmacological therapy sion in the patient with CLI, as limb perfusion is a statin. might only be maintained through the elevated BP.Too profound or rapid a decrease in BP may Hypertension worsen the symptoms, and care must be taken with CLI in the same way as with patients with Although it has been suggested that raised sys- severe carotid disease. tolic and raised diastolic blood pressure (BP) are linked to PAD development, results from Conclusion prospective studies are less convincing. Target levels of blood pressure have been clearly Hypertension has been implicated in the defined in a number of guidelines, For example etiology of PAD and contributes to its vascular 60

VASCULAR SURGERY comorbidity. Blood pressure should be con- trolled to levels consistent with local guidelines. Polypharmacy is likely to be required. Caution is advised when high BP is diagnosed in a patient with CLI, as too rapid a decrease in pres- sure may worsen the limb ischemia.

Sedentary Lifestyle/ Exercise Therapy Intermittent claudication is a symptom of lower Figure 6.2. Walking distance.The improvement in walking dis- limb peripheral arterial disease. It arises when tance is much greater for a graded exercise program compared the blood flow is insufficient to meet the meta- to the best medical management (cilostazol), percutaneous bolic demands of the leg muscles in ambulating transluminal angioplasty (PTA), or placebo. patients. Intermittent claudication is a “lever- aged” disability, as pain increases with walking, patients walk shorter distances, muscle strength erodes, and walking distances continue to decrease. This leads to other negative conse- vessel structure. The progression of coronary quences such as weight gain, hypertension, and lesions can be inhibited in those patients who diabetes. Overall, patients with claudication modify risk factors and engage in regular exer- have a 60% lower functional capacity than cise. Numerous studies have demonstrated a age-matched individuals without the disease significant correlation between exercise and (Eldridge and Hossack, 1987). an increase in vessel diameter. Exercise may Intermittent claudication is a symptom of also induce changes in the lumen diameter in systemic atherosclerosis. At least 60% of pa- patients after coronary angioplasty. Patients tients with claudication have significant disease randomized to a 12-week intervention program of the cerebral or cardiac circulation. Mortality consisting of daily exercise after balloon rates for patients with claudication are very angioplasty of the coronary vasculature had high, with 30% to 50% of patients dying from a significantly lower rate of re-stenosis than cardiovascular causes within 5 years of the patients in the control group. However, the initial diagnosis. A meta-analysis of 21 studies major benefit of exercise is likely due to the on the effects of exercise on patients with clau- training response. dication suggested that the average improve- ment in walking distance was 122% (Gardner Thrombophilia and Poehlman, 1995) and the benefits have been shown to be as high as 180% (Fig. 6.2). Patients under the age of 50 with manifestations The programs with the greatest benefit were of vascular disease have an increased risk of a those in which patients exercised for 30 minutes defined hypercoagulable disorder. Thus, some at least three times a week for 6 months. How- believe that these patients should be screened ever, supervised exercise programs are not for hypercoagulable disorders. In contrast, most currently covered by most medical insurance hematology societies indicate that screening for policies. thrombophilia in arterial disease does not yet There are numerous salutary effects of have an evidence base. exercise that contribute to the reduction of There are two general categories used to cardiovascular events. Exercise is associated describe the hypercoagulable or prothrombotic with beneficial changes in body fat percentage, state: hereditary and acquired. The former is lipoprotein profile, carbohydrate tolerance and often referred to as inherited thrombophilia insulin sensitivity, neurohormonal release, and disease. Acquired thrombophilia is a term re- blood pressure. There is substantial evidence served for well-defined syndromes such as the that regular aerobic exercise can even alter antiphospholipid syndrome (APS). This was 61

MEDICAL MANAGEMENT OF PERIPHERAL ARTERIAL DISEASE previously termed the lupus anticoagulant. to 40% of patients presenting with premature However, the name was changed for two very PAD have been found to have heterozygous good reasons. First, the anticoagulant referred homocystinemia. Pyridoxine supplementation to in this latter term reflects the behavior of reduces the thrombotic events in homozygous the blood in the test tube, and in fact a pro- patients. However, it is not known whether this thrombotic effect is observed in vivo. Second, or other vitamins such as folate affect the course although it can be associated with the connec- of the premature atherosclerosis in the het- tive tissue disease systemic lupus erythemato- erozygous sufferers. sus, this is by no means necessary and we are increasingly recognizing APS occurring in isolation. Although the inherited thrombophilic disor- Vascular Risk Factor ders are historically linked to venous thrombo- Management in Patients with sis, there is some evidence suggesting that they may contribute to arterial thrombosis and in Peripheral Arterial Disease particular in patients with PAD. It has been recorded that inherited thrombophilias link to The presentation of a patient with PAD to a failure of vascular grafting following surgery. In provider of medical care presents an ideal a prospective study hypercoagulability occurs opportunity for the critical assessment of vas- in between 10% and 25% of patients, increasing cular risk factors. Intervention at this time both to about 50% in the presence of clinical markers decreases the risk of coronary and cerebral for thrombophilia. Preoperative identification events and is likely to limit progression of the of such patients is important, as the short- arterial disease in the periphery, although the and medium-term failure rates of the graft are latter is theoretical rather than evidence-based reported to be approximately 50% in such as yet. Thus the modification of vascular risk is patients. Furthermore, such patients are at of crucial importance in the patient with PAD increased risk of deep vein thrombosis during and is likely to become an even more important the operative procedure (see Chapter 5 for the area in the future for clinicians involved with evaluation of these patients). the care of these patients.

Conclusion Drug Treatment of As the inherited hypercoagulable states such as protein C, protein S, antithrombin II deficien- Intermittent Claudication cies,and factor V Leiden occur only infrequently in this patient group, it is not possible to make It is a poor reflection on us, as clinicians a formal recommendation for screening of PAD involved in the care of the PAD patient, that patients. Probably a selective approach is war- angina of the legs is addressed far less aggres- ranted, reserving screening to those patients sively than symptoms of claudication in the with bypass failure, a history of thrombotic heart! Part of the problem reflects the concern events, or atherosclerosis at an early age. about the effectiveness of the drug treatment for the symptoms of intermittent claudication and the consequent unease over the use of financial Homocystinemia resources to purchase these compounds. Guide- lines have been developed for prescribing.There The clinical features of homocystinemia include are four oral drug therapies that have a license the development of premature atherosclerosis, for use as a treatment for IC in the United along with manifestations of arterial and Kingdom and two in the United States: venous thrombosis. Disease severity leads to Naftidrofuryl (Praxilene, not available in the early diagnosis in homozygous patients, but U.S.), oxpentifylline (Trental), cilostazol patients with heterozygous disease present (Pletal), and inositol nicotinate (Hexopal). merely with premature atherosclerosis; 20% These drugs have been evaluated in clinical 62

VASCULAR SURGERY trials in terms of their effectiveness for alleviat- 50%. However, the improvement remains ing the symptoms of leg pain associated with modest compared to exercise programs (180% walking (IC). to 200% improvement). Cilostazol is contraindi- cated in patients with a history of congestive heart failure. Naftidrofuryl Naftidrofuryl is thought to mediate its benefits Inositol Nicotinate (Hexopal) through vasoactivity (vasodilatation) and via a local anesthetic action. Studies have docu- Inositol nicotinate is licensed for use in the mented increased tissue oxygenation, increased United Kingdom for patients with intermittent ADP levels, and reduced lactic acid. The recom- claudication.However,the evidence base for this mended maximum dose is 200mg three times a compound is weak. Of the four double-blind, day. randomized, placebo-controlled trials, three A number of double-blind, placebo- were primary care based and used subjective controlled studies in this area tend to show a or questionable objective criteria for assessment significant placebo response in walking dis- of IC without treadmill use. None showed clear tance approximately 25% improvement in evidence of improvement in symptoms with walking distance with placebo. With Naftidro- drug use. We suggest, therefore, that the drug furyl a further 30% improvement can be may not be of value for patients with IC. expected. These estimates are supported by two meta-analyses. Conclusion Some patients with IC merit drug treatment Pentoxifylline/Oxpentifylline due to the severity of their symptoms. It is rea- sonable to consider Naftidrofuryl or cilostazol This is a rheological agent that has been for the symptomatic relief of moderate disease. approved for the treatment of intermittent The patients, however, should be reviewed 6 to claudication. Only two of the double-blind, 12 months after drug commencement to assess placebo-controlled studies of oxpentifylline that its efficacy and the need for continuation. measured walking distance using treadmills Neither oxpentifylline nor inositol nicotinate showed any statistical improvement in such can be recommended for the treatment of walking distance by patients on oxpentify- symptomatic IC. line. Furthermore, one of these was a retrospec- tive subanalysis of short-distance claudicants, patients who could only walk short distances before claudication ocurred already included in Summary another study. A meta-analysis of ten random- ized, double-blind, controlled studies concluded Peripheral arterial disease is a marker of sys- that the limited amount and quality of data for temic atherosclerosis. Patients with PAD are at this drug precluded an overall reliable estimate high risk for MI and stroke. Thus, an integrative of its efficacy. We recommend, in the absence of approach to risk factor modification and the any consistent evidence,that oxpen- prevention of the sequelae of atherosclerosis tifylline should not be prescribed for use in this is the mainstay of therapy. Patients must be indication. advised to “stop smoking and keep walking.” In addition, however, antiplatelet therapy (e.g., aspirin) is indicated in all patients with periph- Cilostazol eral arterial disease in whom there is no contraindication. Hypertension must be appro- Cilostazol has recently been approved for the priately treated and diabetes mellitus detected treatment of intermittent claudication. It is a and managed optimally. The medical manage- phosphodiesterase inhibitor that has been ment of the symptoms of intermittent claudica- shown in randomized placebo-controlled trials tion should also be addressed if these are to improve walking distance by approximately significantly impairing the patient’s lifestyle. 63

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The key feature, however, in managing these Diener HC, Cunha L, Forbes C, Sivenius J, Smets P, patients is to assess their overall vascular risk Lowenthal A. (1996) J Neurol Sci 143:1–13. Eldridge JE, Hossack KF. (1987) Cardiology 74:236–40. and treat accordingly. Gardner AW, Poehlman ET. (1995) JAMA 274:975–80. Materson BJ, Reda DJ, Cushman WC, et al. (1993) N Engl J Med 328:914–21. References Silagy C, Mant D, Fowler G, Lodge M. (1994) Lancet 343: 139–42. Belch JJ, Sohngen M, Robb R, Voleske P, Sohngen W. (1999) Int Angiol 18:140–4. 7 Anesthesia for Vascular Surgery Jamal J. Hoballah and Farid Moulla

Surgery of the peripheral vascular system Anesthesia Risks requires technical precision and perioperative vigilance. The outcome of vascular procedures Depending on the complexity of the vascular depends on various factors. These factors pathology, a vascular procedure can be per- include patient selection, the procedure per- formed under local, regional, or general anes- formed, the surgeon’s skills, and the periopera- thesia, or a combination of these techniques. tive care. The importance of the perioperative Minimally invasive approaches to vascular care cannot be underestimated. Patients pre- reconstructions are continuing to be developed, senting with a vascular pathology often have allowing for more localized anesthesia. Often it comorbidities. The incidence of coronary artery is assumed that performing a procedure under disease (CAD) in patients with carotid disease local or regional anesthesia results in lower is estimated at 50%. mortality and morbidity and allows earlier Patients with operative lower extremity recovery. Certain trends are apparent in the peripheral vascular disease (PVD) have an literature, although not without controversy, even higher incidence of CAD. Hypertension, comparing these anesthetic techniques and can diabetes, and renal insufficiency are all more be outlined as follows: frequent in patients with PVD compared to the general population. Following aortic surgery, carotid endarterectomy, and lower • While laboratory and monitoring tech- extremity revascularization procedures, the niques are improving, historically many most common major complication is a cardiac perioperative cardiac events are “silent” event. Anesthesia is a risk factor contributing (Steen et al., 1978; Von Knorring and to the perioperative morbidity and mortality Lepantalo et al., 1986). of the vascular patient. The preoperative • There does not appear to be a discernible preparation and the intraoperative manage- difference between regional and general ment can predict and influence the postopera- anesthesia with regard to cardiac risk or tive course. This chapter provides an overview mortality within the field of vascular sur- of the various anesthetic techniques that can gery. There is a large amount of recent con- be used in patients presenting for vascular troversy, practice variability, and research procedures. related to this point (Bode et al., 1996;

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Christopherson et al.,1993; Rigg et al.,2002; abdominal surgery, is becoming the stan- Rivers et al., 1991; Rodgers et al., 2000). dard of care as it gains a wealth of sup- • Regional and general anesthesia offer dif- porting literature. ferent advantages and disadvantages, but • The need for postoperative full anticoagu- both are safe and appropriate for carotid lation with (or the use of even prophylactic endarterectomy (Rockman et al., 1996). subcutaneous doses of) low-molecular- • Combinations of anesthetic techniques weight heparin usually precludes epidural may offer advantages over single-mode catheter use for fear of developing an therapy. epidural hematoma upon the removal of • There is a trend toward less need for the catheter. (immediate postoperative) reoperation for • Both prophylactic and therapeutic un- thrombosis when regional anesthesia is fractionated heparin therapy have to be employed in lower extremity revascular- interrupted to allow for normalization of izations (Christopherson et al., 1993). coagulation prior to removing the epidural • Minimally invasive techniques warrant catheter to avoid a potentially devastating equally minimally insulting anesthetic complication. techniques, contributing to improved out- • Upper extremity vascular procedures can comes over standard surgical intervention. be approached with general, regional, local, or epidural anesthesia. Axillofemoral Because of the relative equity of major anes- bypass is a relative contraindication to thetic risk between regional and general anes- regional anesthesia as is harvesting of arm thesia, the site and probable duration of the veins, although on occasions the vein may procedure itself are often the main determi- be harvested using infiltration of local nants of anesthetic technique. Lower extremity anesthetics. revascularizations typically last from 2 to 6 • The most common vascular surgery, hours with significant variability. A single carotid endarterectomy, has been studied administration of spinal anesthesia offers no extensively, with ongoing debate regarding ability to redose if the initial infiltration wears the effectiveness of intraoperative moni- off. Epidural anesthesia can be continuously toring techniques and regional versus infused both for long procedures and for post- general anesthesia. operative pain management. However, it does little to treat the musculoskeletal complaints of The following sections review the various an awake patient prostrate for several hours. anesthetic techniques available for commonly Conversely, general anesthesia does not allow performed vascular procedures. for patient interaction and requires prophylac- tic measures to avoid the complications of pressure and immobility. It also has the dis- Anesthesia for Endovascular advantage of requiring mechanical ventilation with its potential respiratory complications and Interventions possible hemodynamic stresses with induction or extubation. In most cases, regional and Endovascular procedures vary in complexity general anesthesias are both acceptable alterna- and include diagnostic angiograms, balloon tives for the common vascular surgeries. Some angioplasty and stenting, endovascular aortic issues to remember when deciding on anes- aneurysm treatment with endografts, and vari- thetic techniques are as follows: cose vein treatment by radiofrequency or laser ablation. There is a paucity of studies on the • Open abdominal vascular surgery such as anesthetic requirements of vascular patients for an abdominal aortic aneurysm (AAA) treated by endovascular techniques. In general, is theoretically possible with a celiac axis percutaneous angiography, balloon angioplasty, block or regional anesthesia, but in prac- and stenting are typically performed under tice, warrants general anesthesia. local anesthesia. Infiltration of the skin with 1% • Epidural anesthesia for supplementation lidocaine or bupivacaine can provide ample of general anesthesia, as well as for post- control of pain at the puncture site. It is prefer- operative pain management in major able to premedicate the patient prior to the pro- 67

ANESTHESIA FOR VASCULAR SURGERY cedure and to augment sedation at the onset ments for anesthesia are likely to change as of the intervention. Premedication with 25 to rapidly as the endovascular techniques and 50mg of diphenhydramine and 5mg of devices employed. diazepam given orally 1 hour prior to the pro- cedure relieves many patients of the anxiety and Lower Extremity Vein Therapy anticipation of the intervention. Once the patient is on the catheterization table, sedation Radiofrequency or laser ablation of the greater with 1 to 2mg of lorazepam in addition to 50mg saphenous vein (GSV) is gaining popularity as of fentanyl provides further sedation and excel- an alternative, less invasive method for GSV lent pain control. The skin at the puncture site stripping in the treatment of varicose veins. is infiltrated with the chosen local anesthetic This transforms varicose vein treatment into an and the potential track of the puncture needle office practice and limits the anesthesia needs to is also infiltrated. If during the arterial puncture infiltration of local anesthetics. The skin is typ- the patient complains of pain, additional local ically infiltrated at the site of insertion of the anesthetic can be infiltrated in the area directly sheath through which the laser or radioablation through the Seldinger needle prior to arterial catheter is introduced. Because of the heat puncture. generated with the venous ablation, additional anesthesia is needed along the course of the GSV. Tumescent anesthesia is used for this Endovascular Aortic purpose. Tumescent anesthesia is prepared by Aneurysm Repair the following concentration: 500cc of normal saline in IV bag With respect to aortic aneurysm endovascular treatment, most of the procedures were origi- 16cc of 8.4% sodium bicarbonate solution nally done under general anesthesia. As the 50cc of 1% lidocaine with epinephrine comfort level of the surgeons with the proce- 1:100,000 dure increased, epidural and local anesthesia It is infiltrated along the course of the GSV using started to be used and were noted to be a rea- a long spinal needle. In addition to providing sonable alternative to general anesthesia. The anesthesia to the infiltrated area, tumescent idea of being able to treat an abdominal aortic anesthesia provides a protective layer between aneurysm under local anesthesia is very excit- the vein and the dermis to avoid thermal skin ing and appealing. The question of need for injury during the laser or radiofrequency abla- general anesthesia to treat AAA with endovas- tion. This tumescent anesthesia is also used cular technology has been examined (Henretta during stab avulsion of branch varicosities. In et al., 1999). In 47 patients treated with local addition to providing pain control, it is useful in anesthesia and intravenous sedation without minimizing subcutaneous bleeding from the intubation, only one required conversion ends of the avulsed veins. to general anesthesia. The conversion was needed to repair an injury to the external iliac artery. In the remaining 46, there were lower Anesthesia for Open rates of cardiac complications (zero) and shorter hospital stay when compared to those Aortic Surgery reported with the open technique. Although this study did not compare the results of Physiological and Mechanical endovascular AAA treatment under general Considerations anesthesia versus local or epidural anesthesia, it clearly proved the feasibility and efficacy of Open aortic procedures are typically performed local anesthesia with sedation as an anesthetic under general anesthesia. The anesthesia issues technique for endovascular AAA treatment. At in open aortic surgery depend on the level of the University of Iowa, epidural anesthesia is aortic clamping and the extent of the surgical our preferred technique for endovascular AAA incision. These issues include the need for treatment. However, patients’ wishes and prefer- cardiopulmonary arrest, spinal cord protection, ences often play a decisive role in the selection renal protection, and management of the hemo- of the anesthetic technique used. The require- dynamic changes associated with clamping and 68

VASCULAR SURGERY unclamping of the aorta. Other issues include age of cardiac output blocked by clamping at the need for single-lung ventilation, intraopera- various levels is as follows: infrarenal, 10% to tive hemodynamic monitoring, and the use of 15%; suprarenal, 15% to 25%; and supraceliac, combined epidural and general anesthesia. 55%. The precise percentage varies with certain Although aortic valve, ascending aortic, and disease states, such as aortic occlusive disease arch vessel surgery often require cardiopul- and collateralization. Typically, the surgeon monary bypass, debate still exists regarding works in concert with the anesthesiologist to descending thoracic and suprarenal aortic decrease the afterload (lower the blood pres- surgery. For descending thoracic and suprarenal sure) prior to applying a clamp on the aorta. aortic surgery,the approaches include the clamp In thoracoabdominal procedures where an and sew technique versus the use of an adjunc- aortofemoral or axillofemoral bypass is being tive atriofemoral bypass, aortofemoral bypass, used, the increase in afterload with cross- or temporary axillofemoral bypass. clamping is less pronounced. The use of the car- In patients requiring a thoracoabdominal diopulmonary pump in these procedures incision, the placement of a double-lumen or facilitates easier manipulation and removal of balloon excluder endotracheal tube is essential circulating blood volume to treat hypertension. to deflate the left lung when needed and main- The importance of continuous communication tain the patient on single-lung ventilation. Such between the surgeon and the anesthesia team a maneuver facilitates better exposure to the cannot be overemphasized. Cross-clamping or thoracic aorta. With respect to spinal cord pro- unclamping of the aorta should not be per- tection, maintaining distal and pelvic perfu- formed before the anesthesia team has made all sion, reimplantation of intercostals vessels, the necessary interventions needed to address and control of spinal fluid pressure have been the hemodynamic changes expected with the described as essential to minimizing spinal cord aortic clamp application or removal. ischemia during thoracoabdominal aortic surgery. Although debatable, a spinal catheter is usually inserted prior to induction of general Pharmacological Considerations anesthesia, and the spinal pressure is monitored intraoperatively and for 2 to 3 days after the pro- Although mechanical intervention related to cedure. Spinal fluid is drained to keep the spinal circulating blood volumes are undertaken rou- pressure below 10mm Hg or 14cm H2O. Rever- tinely, so too is pharmacological control of the sal of spinal cord ischemia has been observed in vascular system. Nitroprusside and nitrogly- situations where neurological symptoms have cerine titrations are often employed to decrease developed in the postoperative period in associ- afterload and preload, respectively. The advan- ation with elevated spinal fluid pressure. Debate tages of nitroprusside include its effectiveness still exists with respect to hemodynamic goals in peripheral arteriolodilatation and titratabil- and monitoring, visceral organ protection, and ity. Furthermore, the vasodilatation of the vas- control of cardiac responses to clamp stresses. cular beds causes decreased oxygen extraction Aortic cross-clamping leads to an increase in ratio and decreased cardiac work. Nitroprusside cardiac afterload. This acute increase in after- effects cardiac preload to a lesser extent, but it load is both measurable and manipulable, can possibly decrease the perfusion pressure directly and indirectly. Uncontrolled hyperten- to infra-clamp tissues provided by collateral sion, although tolerated by the healthy heart, arterial supply due to arteriolar dilatation. A can lead to systolic or diastolic dysfunction and common side effect is pulmonary vasoconstric- cardiac decompensation. Blood pressure is tion, arteriovenous shunting, and resultant often viewed as dependent on circulating blood desaturation of blood. Furthermore, prolonged volume, cardiac preload and afterload, and use of nitroprusside can result in systemic cardiac function. All of these factors are cyanide toxicity. Nitroglycerine decreases influenced by, and essentially precluded by, the cardiac preload and is titratable. It vasodilates ability of the heart to withstand the stress of any coronary circulation and indirectly decreases acute physiologic change. The effects of aortic cardiac work. It does not effect infra-clamp cross-clamping are initially mechanical due to organ perfusion and has less systemic toxicity, abrupt change of afterload. The rough percent- seen as methemoglobinemia; however, it is not 69

ANESTHESIA FOR VASCULAR SURGERY as potent as nitroprusside. Other factors for “Cerebral protection” in CEA refers to pro- visceral protection include the use of mannitol tection of the brain from ischemia induced by 12.5g intravenously a few minutes prior to blood flow changes at the time of CEA. Cerebral suprarenal cross-clamping in an attempt to protection can be obtained from a shunt, or decrease renal reperfusion injury. monitoring for its need. The placement of a shunt from the common carotid artery to the internal carotid artery is the standard way Anesthesia in to maintain intracerebral blood flow during CEA. The disadvantages of shunting include Carotid Surgery potential injury to the proximal and distal ends of the shunted vessel (intimal flaps), increased General anesthesia is the traditional anesthetic blood loss, the rare potential for embolism technique for carotid endarterectomy (CEA). In through the shunt, and the technical aspects of 1962 Spencer and Eiseman described a local performing the endarterectomy around the anesthetic technique for CEA.A “cervical block” shunt device. It is for these reasons that selective is regional anesthesia consisting of infiltration shunting is advocated by some. Monitoring for of the paravertebral nerve roots at C2–C4 with significant cerebral effects of carotid cross- one or a mix of local agents. General anesthesia clamping has been shown to decrease the need and regional anesthesia are equally acceptable for shunting, and thus allows for use of a selec- approaches to anesthesia for a patient undergo- tive shunt only if brain tissue is thought to ing a carotid endarterectomy and depend on the be compromised.Electroencephalography,tran- experience of the operative team. scranial Doppler, and ipsilateral stump pres- sure measurement are techniques most often employed. Pros and Cons of Regional Cerebral perfusion pressure (CPP) is equal to Anesthesia and General Anesthesia the mean arterial pressure (MAP) minus the for Carotid Endarterectomy intracranial pressure (ICP). Thus, an additional approach to cerebral protection is to maintain The advantage of general anesthesia goes an elevated MAP during CEA. One approach is beyond keeping the patient motionless. The to maintain the patient’s blood pressure at the brain’s metabolic demand is usually reduced same level or within 20mm Hg higher than with general anesthesia, and thus acts as a the patient’s baseline blood pressure. Again, protective mechanism against ischemia. The this requires a coordinated effort between the disadvantages of general anesthesia in carotid surgeon and anesthesiologist. surgery include the need to routinely place a shunt or the use of EEG or stump pressure mon- itoring to selectively shunt. The decision to Regional Anesthesia Techniques shunt is sometimes determined preoperatively for Carotid Endarterectomy in cases of contralateral occlusion, history of ipsilateral stroke, or known lack of collateral The dermatomal distribution of the neck inner- circulation (from cerebral angiogram). In these vation is in cervical nerves 2 through 4.Regional cases, many surgeons would routinely shunt block anesthesia is targeted at these nerves in a during general anesthesia. paravertebral location. The cervical plexus is The advantages of regional anesthesia are comprised of the anterior divisions of cervical more often seen in a different patient popula- nerves 1 through 4. The plexus sits anterior to tion than with that of general anesthesia. the median scalene and levator scapulae, and Published selective shunt rates in regional behind the sternocleidomastoid muscles. The anesthesia are in the range of 15%, which is a cervical plexus divides into superficial and deep lower rate of shunting than techniques that branches. It is the deep branches that innervate involve monitoring. Regional anesthesia has the deep structures of the neck including the been shown to invoke less postoperative hyper- muscles via an internal and an external series of tension and and reduced posto- nerves. The internal series consists of the fol- perative intensive care unit and hospital stay. lowing nerves: communicating branches, mus- 70

VASCULAR SURGERY cular branches, communicantes cervicales, and also spread to prevertebral (superficial) fascia phrenic. The external series includes the com- and the cervical sympathetic chain, causing municating and the muscular nerves. The Horner’s syndrome or hoarseness secondary to superficial branches of the cervical plexus recurrent laryngeal nerve involvement. become the following sensory nerves: smaller occipital, great auricular, cutaneous cervical, Deep Cervical Plexus Block: and supraclaviculars. A deep cervical plexus block is a paravertebral block targeted to C2 Interscalene Technique through C4. Due to its proximal location, an This technique utilizes the proximity of the cer- effective block involves the superficial and deep vical plexus branches’ proximity to each other branches. A superficial cervical block has the to administer a single dose of anesthetic. Using advantage of not involving any nerves that the same needle as the selective approach but a innervate muscle including the phrenic, and larger syringe to inject 10yo 12cc of an equiva- the disadvantage of not involving the deeper lent anesthetic, a single bolus of local is injected sensory nerves that the deep branches of the in an “interscalene” location as follows: Palpate plexus innervate. the interscalene groove separating the anterior and middle scalenes at a level of the cricoid again Deep Cervical Plexus Block: Selected using Chassaignac’s tubercle of C6. At this loca- tion, enter using a caudal and slightly posterior Division Blockade Technique angle.A C5-6 dermatomal paresthesia is elicited, and 10 to 40cc of local is injected while hold- After placing the patient in a neutral supine ing caudal pressure. A 40-cc injection without position, and appropriately prepping the skin caudal pressure also involves the brachial plexus. for aseptic technique, a 4- or 5-cm 22-gauge Regardless of the amount or pressure used, the needle with a short bevel is used to instill local ipsilateral phrenic nerve is blocked by this proce- anesthetic. An example of local anesthetic that dure,an effect that is usually well tolerated. could be used is a half-and-half mix of 1% The complications of this approach of deep lidocaine and 0.5% bupivacaine.A total of about cervical blockage include phrenic nerve involve- 3 or 4cc of local anesthetic should be used at ment and the same complications as for the each level. To find the proper position for needle selective technique; however, there is a lower placement at all levels, an imaginary line can be chance of inadvertently puncturing the verte- drawn between the tip of the mastoid process bral artery. and Chassaignac’s tubercle of C6, which is pal- pable at the level of, and posterior to, the cricoid cartilage. The C2 injection is performed about Superficial Cervical Plexus Block 1 to 1.5cm below the mastoid process on this Using a 22-gauge, 4-cm needle, local is injected line, just posterior to the sternocleidomastoid. just posterior to the midpoint of the posterior Moving about 1.5cm caudad from the C2 site border of the sternocleidomastoid muscle. The along the same line can place injections at C3 injection should be angled to attempt infiltra- and C4. A horizontal line from the ramus of the tion of the posterior and medial aspects of the mandible posterior can be a guide to the level of muscle. As it only affects the cutaneous nerves, the C4 injection site as well. A slight caudal the complications of this approach are minimal. angle of the needle can prevent the needle from tracking to the intervertebral space, and thus avoiding peridural or spinal anesthesia. If the transverse process is hit with the tip of the Anesthesia for Vascular needle, paresthesias result. This indicates that Surgery of the Lower the needle tip is in the proper vicinity and the injection can be performed. Extremity The complications of this approach to deep cervical block include intravertebral artery Transfemoral thromboembolectomy, focal vein injection causing convulsions,unconsciousness, bypass revisions, and even femorofemoral or temporary blindness. The nerve block can bypasses can be effectively performed under 71

ANESTHESIA FOR VASCULAR SURGERY local anesthesia. In most other procedures Anesthesia for Vascular where long skin incisions, long segments of vein harvesting, deep exposures, and tunneling are Surgery of the Upper required,the options include regional or general anesthesia. Regional anesthesia appears to avoid Extremity the hypercoagulability noted with general anes- thesia and appears to provide an early patency In general, most vascular procedures in the advantage with infrainguinal bypass procedures upper extremity can be managed by local or (Christopherson et al., 1993). However, in pro- regional anesthesia. In spite of the lack of evi- longed procedures, the patient may become dence of the benefit of regional anesthesia restless and uncomfortable due to prolonged versus general anesthesia in randomized studies immobility. in terms of morbidity and mortality, there is Conditions that suggests avoiding regional enough proven or anecdotal benefit in terms of anesthesia include tremor at rest, inability to pain relief, cost-efficiency, and time to dis- follow commands (the level of cooperation of charge. These benefits of regional anesthesia are the patient), peripheral neuropathy limiting the particularly valued in outpatient surgery and sensation of pain of the distal lower extremities, should therefore encourage its use. and a history of lower back surgery or pain. In the presence of severe heart failure or diastolic Regional Anesthesia Techniques dysfunction, general and regional anesthesia have been shown to be similar in overall for the Upper Extremity outcome. In these high-risk patients, local anes- The brachial plexus supplies all of the motor, thesia with monitored anesthesia care is the best and most of the sensory, innervation to the option if the surgical procedure is appropriate upper extremity. It is important to remember for such anesthesia. that the medial aspect of the upper arm to near In the presence of significant pulmonary the elbow is enervated by the medial cutaneous disease [forced expiratory volume in 1 second < and intercostobrachial nerves and not the (FEV1) 1.0], the risk of prolonged intubation brachial plexus. Similarly, the skin on the shoul- or pulmonary infection after endotracheal intu- der is supplied by the “caudal” branches of the bation would indicate regional anesthesia. cervical plexus supply. The common regional However, some patients with significant pul- anesthesia techniques of the upper extremity monary disease are unable to maintain a supine are categorized based on location of surgical position for prolonged periods. dissection. Significant coagulopathy precludes spinal and epidural anesthesia due to the risk of epidural hematoma and subsequent paralysis. Axillary Artery/Vein Dissection Furthermore, an infection either in the region of placement of a regional anesthetic or causing Axillary artery and vein exposure including systemic sepsis usually precludes regional anes- axillofemoral bypass proximal dissection can be thesia due to the risk of seeding the paraspinal performed under local anesthesia, or with an space. intrascalene approach to block the brachial and During procedures involving the foot such cervical plexus. Applying inferior pressure on as toe or forefoot amputations, an ankle the interscalene groove can guide the infiltra- block can be an ideal regional anesthesia. The tion of local anesthesia superiorly along the technique for ankle block involves infiltrating scalene muscles to effect a predominantly cer- the ankle circumferentially with a local anes- vical plexus block. Using less pressure inferiorly thetic just at the level of the medial malleolus. can result in a predominantly brachial plexus Further infiltration of the posterior tibial nerve block. is usually needed to achieve adequate anesthe- sia. The neuropathy associated with diabetes Brachial Artery/Vein can lead to a nearly anesthetic foot, and pro- cedures can be performed with minimal This is the “gray zone” of brachial plexus blocks, anesthesia. as the skin overlying the brachial vessels is often 72

VASCULAR SURGERY at least partially innervated by the medial cuta- that the operative team, surgeons and anes- neous and intercostobrachial nerves.However,if thetists, work in concert throughout any vascu- local anesthesia is used in combination with the lar procedure. brachial plexus block, adequate and safe anes- thesia can result. References Radial, Ulnar, and Antecubital Bode Jr RH, Lewis KP, Zarich SW, et al. (1996) Cardiac Regional Anesthesia outcome after peripheral vascular surgery: comparison of general and regional anesthesia. Anesthesiology The region from the elbow to the wrist is ideal 84:3–13. for a brachial plexus block. The techniques Christopherson R, Beattie C, Frank SM, et al. (1993) Periop- include an intrascalene approach, as mentioned erative morbidity in patients randomized to epidural or above, and a subclavian approach. The intrasca- general anesthesia for lower extremity vascular surgery. Anesthesiology 79:422–34. lene approach, as mentioned in the discussion Henretta JP, Hodgson KJ, Mattos MA, et al. (1999) Feasibil- of cervical plexus block, above, often involves ity of endovascular repair of abdominal aortic the ipsilateral phrenic nerve and possibly some aneurysms with local anesthesia with intravenous cranial nerves.The subclavian approach has less sedation. J Vasc Surg. phrenic nerve involvement (50%) and requires Rigg JRA, Jamrozik K, Myles PS, et al. (2002) Epidural anaes- thesia and analgesia and outcome of major surgery: a smaller volumes of anesthetic, but can lead to randomized trial. Lancet 359:1276–82. pneumothorax. Rivers SP, Scher LA, Sheehan E, Veith FJ. (1991) Epidural versus general anesthesia for infrainguinal arterial reconstruction. J Vasc Surg 14:765–70. Distal Ulnar and Radial Artery, and Rockman CB, Riles TS, Gold M, Lamparello PJ, Giangola G, Hand Surgery Adelman MA. (1996) A comparison of regional and general anesthesia in patients undergoing carotid Local anesthesia is the best option in the com- endarterectomy. J Vasc Surg 24:946–56. pliant patient. Axillary blockade is another Rodgers A, Walker N, Schug S, et al. (2000) Reduction of postoperative mortality and morbidity with epidural or option for distal arm/hand surgery and is rela- spinal anaesthesia: results from overview of random- tively easy and safe. However, axillary blockade ized trials. BMJ 321:1493–7. effects only the forearm, requires arm abduc- Steen PA, Tinker JH, Tarhan S. (1978) Myocardial reinfarc- tion, and can lead to hematoma. tion after anesthesia and surgery. JAMA 239:2566. Von Knorring J, Lepantalo M. (1986) Reduction of periop- erative cardiac complications by electrocardiographic monitoring during treadmill exercise testing before Conclusion peripheral vascular surgery. Surgery 99:610.

Numerous approaches to vascular anesthesia are available. The approach must be tailored to the patient and the procedure. It is important 8 Nonatherosclerotic Vascular Disease Jonathan R.B. Hutt and Alun H. Davies

Vasospastic Disorders ent underlying mechanisms with a similar final end point. In a similar vein, although some factors may not be primary instigators of the Raynaud’s Phenomenon problem, their activation and subsequent action may contribute to the severity of the pathology In 1862 Maurice Raynaud first described the and thus provide therapeutic targets in certain problem of an asphyxia and symmetrical gan- situations. The increasing number of implicated grene of the extremities. Raynaud’s phenome- mechanisms may also indicate the future poten- non is now defined as episodic vasospasm of tial for further delineation of the spectrum of in the extremities. It is classified as disorders associated with Raynaud’s into more either an idiopathic form, known as primary distinct pathological mechanisms. Raynaud’s or Raynaud’s disease,or as secondary Broadly speaking, the etiological factors that Raynaud’s or Raynaud’s syndrome, where it have so far been implicated in the development occurs in the presence of an underlying cause of Raynaud’s can be divided into local factors (Table 8.1). present at the immediate neurovascular level, Raynaud’s has an incidence of up to 5%. It is and more general humoral factors (Fig. 8.1). found worldwide, but due to the common pre- cipitant factor of cold extremities, it appears to The Local Microvascular Unit have a higher incidence in countries with a low Neurogenic Mechanisms ambient temperature. It affects women far more than men at a ratio of 9:1.In the case of primary Vasoconstriction of the cutaneous vessels when Raynaud’s, there is evidence of a genetic predis- induced by cold is regulated by a2 receptors. position, as 25% of sufferers have a first-degree This mechanism is open to derangement in the relative who is affected. pathology of Raynaud’s. It has been shown that The underlying pathophysiology of Ray- sufferers have a reduced basal blood flow, which naud’s presents a complicated picture. The would obviously be further decreased in the overall effect is due to vasospasm of small mus- setting of sympathetic-induced vasoconstric- cular arteries and arterioles. Many factors and tion. Notably, it also appears that baseline mechanisms have been implicated in this cutaneous blood flow is decreased in healthy process, and it is occasionally unclear whether women compared with men, which may provide they are causal as part of the primary pathology an insight into the condition’s preference for or consequential as a result of it. That there are the female sex. Although there is no increase many causes of secondary Raynaud’s is testa- in background catecholamine circulation ment to the fact that there may be subtly differ- detected in affected patients, dermal arteriolar

73 74

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Table 8.1. Secondary causes of Raynaud’s phenomenon samples from Raynaud’s patients show an exag- a Mechanical gerated response to 2-stimulating agents. The Frostbite use of sympathectomy as a therapy and the Vibration documented benefits from the a2-blocking agent Prazosin also support a place for Rheumatological disease abnormal sympathetic activity in Raynaud’s Scleroderma pathophysiology. Systemic lupus erythematosus Another neurological factor is calcitonin Dermatomyositis gene-related peptide, a powerful vasodilator Polymyositis found in cutaneous nerve endings. Response Sjögren’s syndrome to this mediator is unaffected in diseased Takayasu’s arteritis tissue, but immunocytochemistry demonstrates a decrease in calcitonin gene-related peptide levels in the local digital neurons of people with Arterial disease primary and secondary Raynaud’s. Intravenous Brachiocephalic atherosclerosis infusion of calcitonin gene-related peptide has Buerger’s disease also been shown to increase blood flow in the Thoracic outlet syndrome hands and may also help digital ulceration in more severe cases. Vasospastic disorders Migraine Prinzmetal’s angina Endothelial Mechanisms Endocrine disorders At the level of the endothelium, there are a Carcinoid syndrome number of mechanisms which may have been Hypothyroidism implicated in the pathophysiology of Raynaud’s. Endothelin-1 is a vasoconstrictor derived from Blood dyscrasias vascular endothelial cells. Increased levels of Cryoglobulinemia this mediator have been described in patients Paraproteinemia presenting with Raynaud’s. Similarly, nitric Polycythemia oxide, an endogenous vasodilator, appears to be Infective causes present at reduced levels. It appears, however, Parvovirus B19 that these findings may be more consequential Helicobacter pylori than causal. Reports on patients with primary Raynaud’s have not shown increased levels of Drugs endothelin-1, and it is accepted that endothelial Vinblastine damage is more a feature of secondary disease. Bleomycin Moreover, endothelin-1 levels correlate with Methysergide severity of disease and are also shown to Ergot alkaloids decrease in patients with systemic sclerosis as Beta blockers digital ulcers undergo healing. Administration of L-arginine, a precursor of nitric oxide synthesis, has no benefit, and samples from

Figure 8.1. Etiological mechanisms in Raynaud’s phenomenon. Both local and humoral factors have been implicated. CGPR, calcitonin gene-related peptide. 75

NONATHEROSCLEROTIC VASCULAR DISEASE nonaffected arterioles from patients with sys- Erythrocytes temic sclerosis show normal endothelium- mediated vasodilatory responses. This suggests Abnormalities of erythrocyte aggregation and that this mechanism is unlikely to be a primary deformability have been described in Raynaud’s causative one. patients.

Hormonal Humoral Factors Estrogen Cellular Certainly the large predilection for the female Platelets sex that Raynaud’s displays is cause enough to The potential for platelets to act as a significant consider an underlying hormonal basis. Differ- pathological factor is high. Activated platelets ent phases of the menstrual cycle are associated have the ability to aggregate and cause mechan- with varying responses of digital blood flow to ical blockage, or release mediators that are both cold stimuli, which certainly suggests that prothrombotic and stimulate vasoconstriction. female sex hormones may have an etiological Similar to the effects seen on endothelial cells, role. increased expression of a2 receptors on platelets in Raynaud’s patients may provide a lower threshold for activation in the presence of sym- Clinical Factors pathetic stimulation. Platelets from Raynaud’s Raynaud’s is characterized classically by the patients also appear to be hypersensitive to 5- following symptoms: hydroxytryptamine (5-HT) (serotonin) stimu- lation. An increase in activation of platelets is • Initial pallor due to vasoconstriction seen in Raynaud’s, with augmented release of • Cyanosis due to sluggish blood flow the mediators thromboxane A2 and serotonin. • Redness due to hyperemia Similar to endothelin-1, thromboxane A is 2 This gives the classical picture of white, blue, related to disease severity, primarily in second- and then red discoloration described by suf- ary disease. Administration of antagonists to ferers. This picture usually occurs in the pres- this substance, however, does not appear to ence of cold or emotional stress. It may be have a marked effect on disease expression or accompanied by numbness and burning pain, progression. which may be severe as the blood flow returns. The potential for platelets to be primary The most common site to be affected is the etiological agents is also called into question fingers, with the toes involved to a lesser extent. with the interesting observation that sufferers More rarely, other extremities such as the nose, of Glanzmann’s thrombasthenia, who display ears, tongue, or nipple may be affected. The a complete lack of platelet aggregation, may still attacks range from mild, with an asymptomatic suffer attacks of Raynaud’s syndrome. picture when seen by the clinician, to more severe effects with necrosis and gangrene of Neutrophils peripheral tissues. In extreme cases, this may progress from superficial to deep structures and Although they are unlikely to be causative require amputation. factors, circulating neutrophils may certainly In the setting of the presentation of have a propensity for causing damage. Trapping Raynaud’s as a primary complaint rather than and activation in the setting of occluded on the background of known disease, investiga- vessels followed by ischemia and reperfusion tion into underlying causes is required. Up to lead to an escalation of the reactive response in 5% of patients presenting with primary the local vicinity of the arterioles. However, in Raynaud’s ultimately develop a connective primary Raynaud’s, endothelial damage is not tissue disorder. It does appear that there are really a feature. In light of this fact, this mecha- notable differences in the demographics and nism may simply represent an augmenting presentation between primary and secondary effect. disease, as outlined in Table 8.2. 76

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Table 8.2. Clinical differences between primary and ence of underlying disease. Further tests such as secondary Raynaud’s Doppler imaging or angiography of vessels as Feature Primary Secondary well as further blood tests, should be instigated Age at onset £30 ≥30 on the basis of previous indications. A potential Digital gangrene Rare, superficial Common pathway for diagnosis in Raynaud’s is shown in Nail fold capillaries Normal Large and Figure 8.2. tortuous As an idiopathic cause, primary Raynaud’s Auto antibodies Negative or low Frequent should be considered a diagnosis of exclusion, titer to coincide with the following criteria: • Symmetrical vasospastic attacks • Absence of necrosis or gangrene History and examination should be directed • History and physical findings not indica- at the exclusion of secondary causes of tive of secondary cause Raynaud’s phenomenon. History should include • Normal capillaroscopy of nail bed questioning on symptoms of connective tissue • Normal erythrocyte sedimentation rate diseases as well as details of drugs and exposure (ESR) and negative serology for to toxic agents. A history of vibrating tool use, autoantibodies trauma, or positional triggering consistent with thoracic outlet syndrome is also helpful. A follow-up period of 2 years is likely to be Routine examination should not omit careful sufficient to pick up any underlying pathology examination of the peripheral pulses and of what initially appears to be Raynaud’s blood pressure (BP) in both arms, along with disease. The most likely culprits by far that may neck examination for the presence of a cervical reveal themselves are the connective tissue rib. diseases. A further test that can be performed at the consultation is capillaroscopy of the nail fold, where capillary loops lie horizontal to the Treatment surface (Box 8.1). Other techniques for the Acute Ischemia measurement of peripheral blood flow such as analysis of digital systolic pressure during In the setting of acute tissue-threatening cooling or red blood cell velocity in nail fold ischemia, instigation of vasodilatation is the key capillaries have yet to find their way into clini- treatment.Intravenous prostaglandin analogues cal practice. such as iloprost are effective. In the absence of A chest radiograph shows a cervical rib if the availability of such therapy, a short-acting it is present, and may also show changes con- calcium channel blocker such as nifedipine sistent with connective tissue disease. Blood can be given, along with aspirin as antiplatelet testing for autoantibodies or prothrombotic therapy.A digital or wrist block with local anes- states can provide good indicators for the pres- thesia without adrenaline may be beneficial both for pain relief and for the underlying pathology, as it effectively provides a localized chemical sympathectomy. In persistent cases, a prolonged infusion of Box 8.1. Capillaroscopy IV heparin may be required, and in intract- able cases, surgical intervention with localized The nail-fold capillaries can be visualized digital sympathectomy is indicated. through immersion oil placed on the finger. In the absence of tissue-threatening compli- Although best seen with a microscope, they cations, disease therapy is best approached in a can also be viewed using an ophthalmoscope stepwise manner. Increasing levels of inter- set at a diopter of 10–40. In the presence of vention can then be introduced if the disease connective tissue disease, the nail-fold proves refractory to a particular level of therapy. vessels are tortuous and dilated. A potential pathway for the treatment of Raynaud’s disease is shown in Figure 8.3. 77

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Figure 8.2. Algorithm for the History suggestive of diagnosis of Raynaud’s Raynaud’s phenomenon phenomenon.

Exclusion of causative or exacerbating factors • Drugs, Toxins • Environmental agents, Occupation • Trauma

ROUTINE TESTS

• Examination • Capillaroscopy • Blood tests: FBC, U+Es, Autoantibodies • Chest radiograph

In the presence of: In the presence of: • Abnormal capillaroscopy or CXR • Asymmetrical disease • Autoantibodies • Abnormal vascular examination

May require Rheumatic disease likely • Doppler studies/angiography

If all tests normal High suspicion of 20 Raynaud's • Severe symptoms • Evidence of tissue damage/gangrene Low suspicion of 20 Raynaud’s • No digital lesions/gangrene

• These patients can be considered to have primary Raynaud’s • Infrequent follow-up for two years may be necessary to rule Further tests out developing CTD • Thyroid function • Cryoglobulins • Serum protein electrophoresis

If all tests normal

Nonpharmacological Therapy harmful agents. Use of vibration-proof impact tools or in certain cases a change of job may Initial treatment is based on the avoidance of prevent the progression of secondary Raynaud’s precipitants, such as cold and emotional stress. associated with hand–arm vibration syndrome. Prevention of exposure to cold is best based on a total body approach, rather than just localized to fingers and toes, and may include specifically Pharmacological Therapy designed clothing such as heated gloves. The There are a multitude of putative pharmacolog- cessation of contributing factors is also involved ical therapies for Raynaud’s,some of which have at this step. This includes lifestyle modifications a more solid evidence base than others: regarding smoking and caffeine intake, plus other vasoconstricting substances such as Ca+ channel blockers: These have been the cocaine and amphetamines. Any medical thera- mainstay of treatment for some time. The pies that may be contributing to the disease best agents are those based on dihydropy- should be stopped or modified to other, less ridines, due to their decreased action on 78

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Is there threat of tissue loss? Figure 8.3. Algorithm for the treatment of Raynaud’s disease.

YES NO

Nifedipine or similar Doprost infusion +/- Heparin infusion Increase dose of dihydropyridine

Doprost not available or not to berated If no improvement

Nifedipine Aspirin Consider wrist or digital block +/- Heparin infusion Consider trial of • Losartan • Nitroglycerines

If no improvement

If no improvement

Consider suitability for clinical trial Sympathectomy • Proximal sympathectomy • Digital artery sympathectomy

cardiac muscle and relative selectivity Nitroglycerines: The use of topical nitrates for vascular smooth muscle. Classically, may aid in symptomatic relief and in the nifedipine is the drug of choice, but newer reduction of the number of attacks, dihydropyridines such as amlodipine and although side effects may limit their felodipine are also effective. These are usefulness. usually started at a low dose with gradual Prostaglandins: There is good evidence that escalation as required. an intravenous infusion of iloprost, a syn- Angiotensin II receptor antagonists: Trials thetic prostacyclin analogue, is efficacious with losartan show a good efficacy com- in Raynaud’s, certainly in severe disease. pared with nifedipine in reduction of The key to its widespread use in less acute quantity and severity of attacks (Dziadzio settings lies in the production of an effec- et al., 1999). tive oral preparation. However, attempts to Serotonin modulation: The serotonin antago- date to produce a similar effect to that seen nist Ketanserin has been used in treatment, with intravenous administration have particularly in the setting of scleroderma, proved equivocal and have been troubled although its evidence base may be ques- by a high incidence of side effects. tionable. There is also some evidence that Future possibilities: Further medical treat- selective serotonin reuptake inhibitors ments are likely to continue to appear, in (SSRIs) such as fluoxetine may have a the light of the large quantity of mooted beneficial effect. causative factors. Initial trials with calci- 79

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tonin gene-related peptide certainly indi- The clinical picture varies in severity.Therapy cate potential for development. Further with aspirin and vasoconstrictive agents can be delineation of the genomics behind helpful, and treatment of the underlying disease primary Raynaud’s may show the road to may aid symptoms in secondary disease. more interventional possibilities in the setting of gene therapy. Acrocyanosis

Surgical Therapy This presents as a symmetric cyanosis of the hands or less commonly of the feet, which is Due to its invasive nature as well as its inherent both persistent and painless. Affected body complications, surgery for Raynaud’s is usually parts show decreased temperature and blue dis- reserved for cases that are refractory to medical coloration, and they may be swollen and sweaty. therapy. The main surgical option is sympa- Examination of peripheral pulses is normal. thectomy, which may be performed as a proxi- Generally, it is not a harbinger of underlying or mal procedure, or as a microsurgical localized threatening pathology, and supportive treat- operation: ment with reassurance and advice about avoiding the cold is usually sufficient. Upper limb: This involves destruction of the second and third thoracic ganglia and their interconnections, which may be performed through a number of surgical approaches. Vasculitis Results are disappointing in terms of Vasculitis is broadly defined as inflammation of relapse rate, although it may still have a the vessel wall. It covers a wide range of clinical role in severe cases. and pathological entities, which have both Lower Limb: This involves destruction of confusing similarities and yet important dis- the second, third and sometimes fourth tinctions, most notably in their treatment and lumbar sympathetic ganglia plus intercon- prognosis. nections. It appears to be a more effective Classification of these diseases is compli- therapy than the similar procedure in the cated, as there is considerable overlap both in upper limb. clinical presentation and histological appear- Another option, this one microsurgical, is ance. The most common approach used is to digital artery sympathectomy, a more effective classify them by consideration of the size of procedure than proximal sympathectomy. the vessels that the disease affects (Table 8.3). Although effective, its place probably lies in Vasculitis that affects the smaller arteries can be treatment of tissue-threatening disease or in further classified according to whether or not cases refractory to medical therapy. antineutrophil cytoplasmic antibodies (ANCAs) are found. Such a distinction is possible at a his- tological level, as only those associated with Other Vasospastic Disorders ANCAs affect the small arteries, with the others affecting arterioles, venules, and capillaries. The underlying pathophysiology of many of the noninfective vasculitides appears to have an This is a rare condition characterized by vasodi- immunological basis. This is clear not only from lation associated with erythema and increased the temporal associations of some of the con- temperature of the extremities along with a ditions with certain viral infection, but also burning pain. Similarly to Raynaud’s phenome- from the fact that the majority are treated with non, it may occur in an idiopathic form or various combinations of immunosuppressants. secondary to other disease. Associated pathol- Their clinical presentation arises from the ogy includes hypertension, myeloproliferative consequences of vessel wall inflammation. disorders, diabetes, rheumatic disease such as These include thrombosis and subsequent rheumatoid arthritis or systemic lupus erythe- ischemia or infarction, aneurysm formation, matosus (SLE), gout, spinal cord disease, and and hemorrhage. The extremely broad range of multiple sclerosis. clinical phenomena and affected target vessels 80

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Table 8.3. Classification of the vasculitides Features of vascular insufficiency may also be Large-vessel vasculitis present, such as jaw claudication, or, more Giant cell arteritis rarely, tongue or limb claudication. These symp- Takayasu’s arteritis toms may be accompanied by systemic symp- Medium-vessel vasculitis toms of fever, malaise, fatigue, and a sore throat. Kawasaki’s disease The most feared complication is involve- Polyarteritis nodosa ment of the ophthalmic artery. This leads to ischemia of the optic nerve and sudden painless Small-vessel vasculitis visual loss, which can be temporary or may be ANCA associated Wegener’s granulomatosis permanent. Churg-Strauss syndrome On examination, there may be swelling and Microscopic polyangiitis tenderness of affected superficial arteries,which will be pulseless. The most notable finding on Not ANCA associated simple blood tests is a significantly raised ESR Henoch-Schönlein purpura Cryoglobulinemic vasculitis and C-reactive protein (CRP). Cutaneous leukocytoclastic angiitis The key to diagnosis of this condition is obtaining histology from an arterial biopsy, ANCA, antineutrophil cytoplasmic antibody. which is usually taken from the temporal arter- ies. Due to the nature of the disease, which means that the vasculitides present to a myriad occurs as skip lesions, it is important to take a of clinicians: dermatologists, rheumatologists, multiple sections, each of an amount of at least and gastrointestinal(GI) and vascular surgeons. 3 to 5cm. The most effective treatment is corticos- teroids, and if a diagnosis of giant cell arteritis Large-Vessel Vasculitis (GCA) is suspected, immediate initiation of Giant Cell Arteritis steroid therapy is required to prevent the onset of blindness. A prompt biopsy should then be This is a granulomatous inflammatory disease organized, preferably within 7 days of starting of the aorta and its branches. It has a tendency the steroid course. This reduces the possibility to affect the extracranial branches of the carotid of a negative biopsy in an affected patient, artery, hence its other name of temporal arteri- avoiding the clinical conundrum that follows tis. It was first described by Sir Jonathan of a patient on long-term steroids without a Hutchinson in 1890, who noticed it in a retired definitive diagnosis. hospital porter who was unable to wear his hat In 75% of patients, the disease settles within due to tender and inflamed temporal arteries. It a period of 3 years,but in others it proves refrac- is a disease that is predominantly seen in Euro- tory to treatment. As in all diseases treated with peans over 50 years old,and has a slightly higher long-term steroids, the side effects of the treat- incidence in women, with a male to female ratio ment itself can lead to difficulties. Currently, of 1:2. Incidence can be up to 25/100,000 in the however, it appears that no steroid-sparing older age groups. Although the actual cause agent has emerged as a suitable alternative or remains a mystery, it has a strong association adjunct. with polymyalgia rheumatica, which is present in up to 50% of cases. Both these conditions Takayasu’s Arteritis share genetic risk factors and geographical populations. In 1908 Mikito Takayasu, a Japanese ophthal- At a microscopic level, there is intimal thick- mologist, described the association of retinal ening and edema. A chronic inflammatory arteriovenous anastomoses and absent upper picture is seen with giant cell and granuloma extremity pulses. Takayasu’s arteritis is a rare formation. granulomatous arteritis of the aorta and its The usual clinical presentation is with severe major branches. It has a predilection for unilateral occipital or temporal headaches. females, and tends to affect people in their There is scalp tenderness, which classically second and third decades, although it has been becomes evident on brushing or combing hair. reported in patients as young as 6 months and 81

NONATHEROSCLEROTIC VASCULAR DISEASE in adults at every age. Although it is encoun- Treatment tered worldwide, it is especially prevalent in people of Asian descent. Some patients demonstrate a self-limiting Pathologically, Takayasu’s arteritis somewhat disease that requires minimal intervention, resembles giant cell arteritis, displaying severe whereas others require more intensive therapy. necrotizing inflammation that leads to marked intimal thickening. This causes eventual nar- Medical rowing and occlusion of the lumen. It can also weaken the vessel wall, providing a predisposi- In the first instance, treatment is with glucocor- tion to aneurysm formation. ticoids. If the disease proves refractory to Clinically, patients suffer from systemic steroid therapy, or if the patient is unable to be symptoms such as fever, malaise, weight loss, weaned off their long-term use, further treat- arthralgia or myalgia, and night sweats. More ment with cytotoxic agents is indicated. specific symptoms are related to the affected Adjunct therapy with methotrexate is effective arterial system and related end-organ ischemia, in increasing progression to remission as well a (Table 8.4). Clinical presentation can vary from having steroid-sparing effects. Cyclophos- incidental discovery in the asymptomatic pa- phamide has similar properties, but due to its tient to a catastrophic event. significant toxicity is probably best used as a Physical examination may reveal bruits or third-line treatment in those who are intolerant decreased pulses (Takayasu’s is also known as of or nonresponsive to methotrexate. pulseless arteritis). Blood pressure may be ele- vated, and also asymmetrical due to subclavian Surgical stenosis. There may be valvular regurgitation and arterial tenderness. This latter sign may be There is a place for open vascular surgery and especially noticeable over the carotids. endovascular options in the cure of fixed vascu- Investigation is primarily by arteriography. lar lesions producing significant ischemia. Indi- Neither the level of symptoms nor other indica- cations include cerebral hypoperfusion, tors of disease such as the ESR provide a clear hypertension due to renovascular disease, and indication of disease extent or severity.As a rule, aneurysms or valvular insufficiency. Clinically these indicators are thus not a good guide to significant improvement of symptoms is usually management. possible with surgery, although restenosis is common.

Table 8.4. Site-dependent presentation of Takayasu’s arteritis Prognosis Clinical presentation and severity depend on: Site Takayasu’s is a chronic disease with a 45% Degree of stenosis relapse rate, although 23% of patients never Availability of collateral blood supply reach a state of remission. Following diagnosis, survival rates are greater than 80%. However, Subclavian: Arm claudication, Raynaud’s the disease still carries a significant morbidity. Carotids: Visual changes, syncope,TIAs/ stroke Vertebrals: Visual changes, dizziness Cogan’s Syndrome Aortic arch: Aortic insufficiency, CHF Aorta This rare disorder of young adults of either sex (includes main enteric branches): warrants a mention at this point primarily due Abdominal pain, nausea, to the vessel it affects. It is an inflammatory vomiting process that leads to interstitial keratitis and Renal arteries: Hypertension/renal failure may lead to permanent hearing damage or Iliac arteries: Leg claudication effects on the vestibuloauditory system, Pulmonary arteries: Atypical chest pain, dyspnea Coronary arteries: Chest pain/MI although these effects appear unrelated to the vasculitic phenomena. From a vascular point CHF, chronic heart failure; MI, myocardial infarction; TIA, transient of view, patients may suffer or other ischemic attack. large-vessel inflammation. The primary source 82

VASCULAR SURGERY of morbidity is cardiovascular involvement and Table 8.6. Other clinical features of Kawasaki’s disease auditory problems. System Feature Treatment is with prednisolone, and is indi- Cardiovascular Pancarditis cated for severe ocular or auditory disease and Gastrointestinal Diarrhea vasculitis. Prompt treatment at the first sign of Genitourinary Albuminuria hearing damage improves the prognosis for Neurological Aseptic meningitis overall hearing loss and return of function. Joints Arthralgia Blood Leukocytosis, thrombocytosis, raised Medium-Vessel Vasculitis C-reactive protein Kawasaki’s Disease

Kawasaki’s disease was first identified in 1967 by aneurysms. These occur 1 to 4 weeks after the Tomisahu Kawasaki, a Japanese pediatrician, onset of fever, and are seen in up to 25% of and is also called mucocutaneous lymph node untreated cases. Thus, monitoring of the disease syndrome. Although it is seen in adults, this is is usually structured with an electrocardiogram primarily a disease of childhood, and the major (ECG) performed in the first week of illness, cause of acquired heart disease in children with an echocardiogram both initially at diag- in the United States and Japan. Despite the nosis and repeated 2 to 4 weeks later. original demographical description, it is a Treatment is twofold. High-dose IV disease that is found worldwide. In the United immunoglobulin is given as a single infusion. Kingdom the incidence is less than 5/100,000 in This prevents the formation of coronary children less than 5 years old; 80% of sufferers aneurysms but also decreases fever and are in this age bracket, and males are affected inflammation in the myocardium. Patients are with slightly greater frequency than females at also given aspirin as an antithrombotic a ratio of 2:1. measure. In certain cases, long-term follow-up and anticoagulation may be required. Clinical Factors The condition begins with an acute febrile Polyarteritis Nodosa illness. This is followed by a polymorphic rash Polyarteritis nodosa (PAN) was the name even- that may affect any part of the body, congestion tually given to the disease process in the first of the conjunctivae, dryness and erythema of definitive report of a patient with necrotizing the oral mucosa, cervical lymphadenopathy, and arteritis, which was written in 1866. For some erythematous edema of the palms and soles. time, before it was clear that there were fur- These features are the criteria for the diagnosis ther underlying pathological mechanisms, all of Kawasaki disease (Table 8.5). Other clinical patients presenting with necrotizing arteritis features are outlined in Table 8.6. were given a diagnosis of PAN. In truth, it is an The major cause of morbidity and mortality uncommon disorder. Unlike other vasculitic in the disease arises from the cardiovascular disorders, PAN is most frequently observed in complications, including pancarditis, but more middle-aged men. It often leads to severe sys- specifically the vasculitic changes in the coro- temic complications affecting many of the organ nary arteries may lead to the formation of systems. The underlying pathology of PAN is one of florid acute inflammatory changes seen in a pattern of fibrinoid necrosis. This is similar to what is seen in models of immune complex Table 8.5. Diagnostic criteria for Kawasaki’s disease vasculitis, and there is some evidence that Fever plus: certain viruses have associations with the devel- Rash opment of PAN. These include the hepatitis B Conjunctival injection and C viruses and HIV. Clinically, the patient Oral mucosal changes may present with a number of complaints, due Brawny induration of extremities Cervical lymphadenopathy to the widespread nature of the disease (Table 8.7). 83

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Table 8.7. Clinical manifestations of polyarteritis nodosa involvement. Five-year survival with treatment System Manifestation is 80%, and it is a disease that relapses only Cardiovascular Coronary arteritis may lead to MI or infrequently. HF Respiratory Asthmatic symptoms + hemoptysis, Small-Vessel Vasculitis (rare) Estimates of incidence of the small-vessel vas- Gastrointestinal Hemorrhage and mucosal ulceration culitides vary, most likely due to variations in Presentation may mimic the acute the diagnosis. They share similar nonspecific abdomen systemic features such as fever, malaise, weight Genitourinary Hematuria loss, arthralgia, and myalgia. Investigation of Neurological Mononeuritis multiplex these patients should include screening for anti- (involvement of vasa nervorum) neutrophil cytoplasmic antibodies (Box 8.2). Broadly speaking, the vasculitides of the Joints Subcutaneous nodules,* small vessels can be divided into those in which hemorrhage, and gangrene the ANCAs are positive or negative (Table 8.8). Livedo reticularis, (seen if chronic) Blood Leukocytosis, thrombocytosis, raised CRP Wegener’s Granulomatosis In Wegener’s (named for Friedrich Wegener, * These occur due to the involvement of subcutaneous arteries and, although uncommon, they are part of the reason why the disease a German pathologist, 1907–1990), the small was originally named. arteries are predominantly affected above all CRP,C-reactive protein; HF, heart failure; MI, myocardial infarction; others. It may occur at any age, and appears to TIA, transient ischemic attack. show no predilection for either sex (Hoffman et al., 1992). Pathologically, it has a pattern of necrotizing Blood tests in PAN reveal anemia, leukocyto- granulomatous vasculitis and is typically char- sis, and a raised ESR; ANCA is rarely positive acterized by lesions that involve three main in classic PAN. Diagnosis is primarily by two methods. Histologically, biopsied lesions show a classical pattern of necrotizing arteritis, whereas angiography reveals microaneurysms, Box 8.2. Antineutrophil which may be found in hepatic, intestinal, or renal vessels. cytoplasmic antibodies Treatment of the condition is primarily with immunosuppressants. Therapy is initially with Antineutrophil cytoplasmic antibodies corticosteroids, but further agents such as (ANCA) azathioprine or cyclophosphamide may be indi- There are two primary types of ANCA, cated in life-threatening disease. differentiated on the basis of their pattern In cases where the vasculitis occurs in a of immunofluorescence on ethanol-fixed picture of viral infection, control of the neutrophils. inflammation with immunosuppression may be cANCA necessary before effective antiviral therapy can Antibodies directed against serine pro- be considered. However, combination antiviral tease proteinase 3 (PR3). therapy may prevent the problems of conven- These give a cytoplasmic pattern. tional treatment, which may enhance viral repli- pANCA cation, increasing the chance of progression to Antibodies directed against the enzyme chronic infection. In viral-associated vasculitis, myeloperoxidase (MPO). plasma exchanges may also be considered, as These give a perinuclear pattern. they are effective in reducing the amount of The ANCA typing can be combined with circulating immune complexes. antigen-specific testing for PR3 and MPO to The prognosis, perhaps unsurprisingly, is increase specificity. worse in those patients who suffer multisystem 84

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Table 8.8. Distribution of ANCA among the small vessel before succumbing to pulmonary or renal vasculitides failure. Even with treatment, relapse is seen in ANCA positive ANCA negative around 50% of cases. The presence of lung or Wegener’s granulomatosis Henoch-Schönlein kidney involvement at diagnosis is a poor purpura prognostic indicator. Wegener’s also has an Churg-Strauss syndrome Cutaneous leukoclastic especially mutilating form, known as midline angiitis granuloma, which carries a particularly poor Microscopic polyangiitis Cryoglobulinemic outlook. vasculitis Therapy is with a combination of glucocorti- coids and other immunosuppressants. Treat- ANCA, antineutrophil cytoplasmic antibody. ment with prednisolone alone is ineffective, and the decision on which further agent to use is based on a number of factors. In active organ systems: the upper respiratory tract, the Wegener’s where the disease is life threatening, lungs, and the kidneys. Greater than 90% of treatment with prednisolone is combined with patients seek help for symptoms related to the cyclophosphamide. This leads to a 90% respiratory tract. improvement rate, achieving complete remis- Patients suffer initially from severe rhinor- sion in around 75% and giving a survival rate rhea. This is followed by nasal and sinus of 80%. The main drawback with this regimen inflammation, which eventually leads to carti- is the significant toxicity associated with laginous ischemia, the sequelae of which are cyclophosphamide use.To avoid it,a progressive perforation of the nasal septum and saddlenose approach may be needed, using cyclophos- deformity of the nasal bridge. Tracheal phamide until the disease is in remission, then inflammation and sclerosis lead to stridor and changing to another agent such as methotrexate potentially dangerous airway stenosis. This par- or azathioprine, which can then be tapered out. ticular complication is more common in chil- In active disease that is not life threatening, dren who are affected. Disease activity in the combination treatment with prednisolone and lower respiratory tract leads to cough, hemopt- methotrexate is equally as good at maintain- ysis, and pleuritic pain. Renal tract disease man- ing remission compared with a cyclophos- ifests as glomerulonephritis. This is present in phamide, and a similar regimen may also be only 20% of patients at the time of diagnosis, used in those patients who are intolerant of but appears overall in 80% eventually. cyclophosphamide. A chest radiograph may show nodular masses, which can be multiple. There may also Churg-Strauss Syndrome be ground-glass infiltration and cavitation.Over time, the lesions show a migratory pattern, dis- Churg-Strauss syndrome, named for Jakob appearing in one area only for new lesions to Churg, a Polish-American pathologist (1910– appear in others. 1966) and Lotte Strauss, an American pathol- The typical histology of Wegener’s is best ogist (1913–1985), has an incidence of about seen in the kidney. A renal biopsy demonstrates 3 per million. The typical patient is usually necrotizing microvascular glomerulonephritis. male and in the fifth decade of life. Classically However, diagnosis is often by nonrenal biopsy, the syndrome is a triad of rhinitis and asthma, which demonstrates the granulomatous necro- eosinophilia, and systemic vasculitis. Because tizing inflammation with neutrophil aggrega- of its makeup, there are a number of theories tion and vasculitis. The site of biopsy is about the underlying pathophysiology. It may important. An upper airway biopsy, although be a progression of an allergic phenomenon, easy to perform, demonstrates diagnostic or a primary vasculitis that has an asthmatic changes in only 20% of cases. A more invasive component due to the involvement of biopsy of the lung parenchyma shows the diag- eosinophils. nosis in 90%. Pathologically, the picture is one of Before treatment became available, patients eosinophilic infiltration, which typically affects suffering from Wegener’s granulomatosis would the lung, peripheral nerves, and the skin. Histo- have a mean survival time of only 5 months logically, a necrotizing vasculitis of the small 85

NONATHEROSCLEROTIC VASCULAR DISEASE arteries is seen along with extravascular, it is characterized by the deposition in vascular allergic granulomas. structures of immunoglobulin A (IgA)-contain- Although initially presenting as above, the ing immune complexes. It has a preference for syndrome has a progressive nature, which is venules, capillaries, and arterioles. The common eventually vasculitic and involves the lungs, clinical presentation is usually with arthralgia, nerves, heart, and the GI and renal tracts. A colicky abdominal pain, and a purpuric rash; complete blood count shows a high eosinophil 50% of sufferers have hematuria or proteinuria. count. However, this compromises renal function in Treatment is primarily with corticosteroids only 15%. alone, although in life-threatening cases It is important to distinguish Henoch- cyclophosphamide can be added. Due to its Schönlein as a distinct pathological entity from association, it may be difficult to taper pred- other small-vessel vasculitides. It has an excel- nisolone treatment when the vasculitic parts of lent prognosis, and supportive care is usually the disease are in remission, as this may lead to sufficient for most patients, in contrast to the asthmatic exacerbations. life-threatening disease that can be caused by the other inflammatory disorders. End-stage renal failure occurs in less than 5% of patients. Microscopic Polyangiitis Another vasculitis that primarily affects the Cutaneous Leukocytoclastic Angiitis small vessels, microscopic polyangiitis has only recently been distinguished from PAN, and for This is the most common cutaneous vasculitic this reason there is a relative dearth of data lesion. It is an acute purpuric skin lesion, under- about the disease. Pathological distinction from lying which is an inflammation of the dermal PAN is accepted to be on the basis that micro- postcapillary venules. Although primarily scopic polyangiitis leads to vasculitis in vessels affecting the skin, it may also be associated with smaller than arteries, whereas PAN can be diag- an arthralgia or glomerulonephritis. Etiologi- nosed if these vessels are not involved. Histo- cally, there is some indication that viral agents logically, it represents a necrotizing vasculitis, such as hepatitis C virus may play a part. It with few immune deposits and no granuloma can also result from drug therapy with certain formation. agents such as sulfonamides or penicillin. Clinically, microscopic polyangiitis mainly Most patients suffer a single episode, with affects the kidney, presenting with glomeru- resolution occurring over a few months. About lonephritis and hemoptysis. It may also be asso- 10% suffer recurrent disease at varying inter- ciated with mononeuritis multiplex and fever. vals. Symptomatic relief from cutaneous irrita- Diagnosis is usually based on clinical features, tion and associated arthralgia and myalgia is testing for ANCAs, and renal biopsy. It can be possible with antihistamines and nonsteroidal severe, and survival rates at 5 years may be as antiinflammatory drugs. Treatment of severe low as 74%. In disease that is potentially life cutaneous disease is with corticosteroids. threatening, treatment is with prednisolone and cyclophosphamide. Cryoglobulinemic Vasculitis Cryoglobulins are cold-precipitable immuno- Non–Antineutrophil Cytoplasmic globulins that may be monoclonal or polyclonal. Antibody–Associated Small-Vessel They are encountered in myriad disease pic- tures including lymphoid and plasma cell neo- Vasculitis plasms and chronic infective and inflammatory Henoch-Schönlein Purpura processes. Essential mixed cryoglobulinemia describes the presence of cryoglobulins in the This is the most common systemic vasculitis in absence of any precipitating underlying pathol- children. It is named for Edouard Henoch, a ogy. Although this has been described his- German pediatrician (1820–1910), and Johann torically, it appears that most of these cases Schönlein, a German physician (1793–1864). are related to infection with hepatitis C virus The peak incidence is at 5 years. Pathologically, (HCV). 86

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Vasculitis occurring in association with cryo- rence. This much is clear from observations of globulins affects people at about 50 years of age. the patient base, although interestingly the A clinical picture of palpable purpuric lesions, actual underlying mechanism has proved arthritis, weakness, neuropathy, and glomeru- elusive. The indications appear to be that of an lonephritis is seen. The latter complication has immune-mediated pathology, and a high preva- an association with a poor prognosis, if not lence has been associated with certain tobacco always a progression to end-stage renal failure. types in India and Bangladesh. Histologically, A useful diagnostic test is to look at complement the disease manifests as an intense endarteritis levels. A distinctive picture of low levels of C4 with cellular infiltration, giant cell foci, and the with normal or slightly low C3 is seen. Renal presence of cell rich thrombi, which may show biopsy shows an endothelial membranoprolifer- recanalization. Other immunological markers ative glomerulonephritis with intraglomerular have also been demonstrated within the intima deposits. of the vessels. The internal elastic lamina and Mild disease can be approached symptomati- overall vascular wall architecture are well cally. Antiviral therapy that produces a sus- preserved. tained response appears to be the most effective Clinically, there is a picture of ischemia of the way of treating HCV-associated cryoglobuline- distal extremities with rest pain, ulceration, and mic vasculitis. In severe disease, the use of gangrene (Ohta and Shionoya, 1988). Both immunosuppressants has been advocated, upper limb and lower limb disease is seen in although as expected, these agents may lead to 40% of cases. In 10% there is only upper limb an increase in HCV viremia. involvement, and in 50% only the lower limb is affected. Claudication is a rare symptom due to the distal nature of the diseases, and if present Miscellaneous Disorders occurs most notably on the instep. Diagnosis is based both on typical clinical Buerger’s Disease features as well as the exclusion of other causes, as outlined in Table 8.9. This eponymous disease, named for Leo The investigations are thus directed initially Buerger, an Austrian-born American physician at ruling out other conditions. The next step is and urologist (1879–1943), is also known by the to image the affected vessels. Arteriograms of more descriptive term thromboangiitis obliter- the upper limb often show occluded radial and ans. It is an occlusive disease of the small and ulnar arteries that have become tortuous where medium-size arteries of the extremities, which they have recanalized. There may also be it affects in a segmental fashion. It primarily “pruning” of the digital arteries. In the lower affects young people, with a median age of 34 limb, the vessels are often normal down to the years. Initial descriptions by Buerger noted a popliteal trifurcation. Distal to this, segmental strong predilection of the disease for men, occlusive disease is seen. This frequently affecting 2 of 500 cases that he reported. More affects the tibial branches more than the recent studies report a male to female ratio of popliteal. None of these changes, however, is up to 5:1. The disease also has a somewhat pathognomonic. unusual geographical distribution. It has a low Although the treatment of infected lesions incidence in people of European descent, but is with antibiotics and debridement where neces- high in India, Japan, Korea, and the Middle East, sary is similar to that of other ischemic disease, especially among Jews of Ashkenazi descent. In the mainstay of therapy in Buerger’s disease is fact, in this latter micropopulation, Buerger’s the cessation of smoking. Recurrence is almost disease accounts for up to 80% of cases of always associated with resumption of tobacco peripheral vascular disease. usage, and new ischemic lesions are rare The primary causative factor associated with without reexposure. Conversely, persistent Buerger’s disease is tobacco usage. Although abstinence from tobacco results in quiescence of this usually manifests as smoking, it has also the disease process. As the lesions in Buerger’s been observed in patients who chew tobacco. disease appear to have healing potential, this Tobacco use holds the key not only to causation intervention can have a significant clinical but also to persistence, progression, and recur- effect. 87

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Table 8.9. Features of Buerger’s disease regard to limb loss. Some form of amputation, 1. Distal extremity ischaemic symptoms ranging from digital to major lower limb 2. Exclusion of other causes removal, is required in up to 20% of patients. ᭺ Proximal embolic source The extreme importance of smoking is again ᭺ Localised lesion (popliteal entrapment, cystic evident here. In one study, 94% of patients who disease quit smoking remained amputation free, ᭺ Vasculitis whereas 43% of those who continued eventually ᭺ Drugs—ergot required at least one amputation. Interestingly, ᭺ Hypercoagulable states and perhaps due to the distal nature of the ᭺ Trauma 3. Onset at <45yrs vasculature affected, the long-term survival of 4. Tobacco usage patients with Buerger’s disease is affected only 5. Supporting features very slightly, with life expectancies approaching ᭺ Migratory superficial that of the normal population. ᭺ Raynaud’s phenomenon ᭺ Upper limb involvement Distal extremity ischemic symptoms Exclusion of other causes This is a noninflammatory, nonatherosclerotic Proximal embolic source vascular disease affecting arteries of small and Localized lesion (popliteal entrapment, cystic medium size. It appears in a variety of histol- disease) ogical manifestations depending on the arterial Vasculitis wall layer that is most significantly involved Drugs: ergot (Table 8.10). Although different types show a Hypercoagulable states slight variation epidemiologically, the common- Trauma est form has a predilection for females in their Onset at <45 years of age second to fourth decades. Disease has been Tobacco usage noted in patients as young as 2 months old. Supporting features The etiology of fibromuscular dysplasia Migratory superficial phlebitis (FMD) is still unclear, but it appears to be mul- Raynaud’s phenomenon Upper limb involvement tifactorial. Suggested factors include localized ischemia due to poor perfusion from the vasa vasorum, sequelae of mechanical damage, and there is evidence for a familial link. There are also many documented associations, both with Other options are used in refractory progres- diseases such as pheochromocytoma, neurofi- sive disease. Sympathectomy has been advo- bromatosis, Ehlers-Danlos, Alport’s, Rubella cated, and surgical bypass may occasionally be syndrome, and heterozygous a1-antitrypsin attempted. This latter treatment, however, has deficiency as well as other factors such as a poor rate of success. The results are affected ergotamine and methysergide. not only due to the segmental, distal nature of Symptomatic disease from FMD may result the disease, but also because the associated from vessel stenosis, dissection, embolization, phlebitis makes the veins poor conduits. thrombosis, or rupture of associated ane- A number of new treatments are being eval- urysms. Disease and thus symptoms have been uated, including implantation of spinal cord recorded across the whole spectrum of the stimulators and intramuscular injections of vascular endothelial growth factor. The use of iloprost has also been advocated, although a Table 8.10. Histological classification of fibromuscular significant clinical effect seems to be absent. dysplasia The final surgical option is amputation. It Classification Frequency (%) should be noted that healing of surgical ampu- tation is much improved when patients are free Intimal fibroplasia 5 from tobacco usage. Medial fibroplasias 1–2 Medial hyperplasia 80–90 Compared with other necrotizing arteritides, Perimedial fibroplasia 10–15 Buerger’s disease has a worse prognosis with 88

VASCULAR SURGERY vascular bed, and it is likely that there will be that as with other reno-occlusive disease subclinical disease present in other areas in angiotensin-converting enzyme (ACE) inhi- most patients. The most common manifesta- bitors should be avoided. If pharmacological tions are hypertension from renovascular treatment fails, there are a number of options. disease and stroke from carotid disease. In Percutaneous transluminal angioplasty (PTA) is terms of the kidney, a significant proportion of an effective intervention, and although it is renovascular disease arises on a background of associated with up to a one in five re-stenosis FMD, the primary result of which is hyperten- rate, the rate of reappearance of hypertension is sion. However, as renovascular disease is a lower. Given the success in actually curing relatively uncommon cause of hypertension in hypertension, PTA should probably be consid- itself, FMD is not a major contributing factor to ered earlier in younger patients to avoid unnec- adult hypertension. When it affects the cere- essarily long courses of medical therapy along brovascular system, it is predominantly seen in with progressive deterioration of renal func- the internal carotid artery, and frequently is tion. There are also a number of surgical seen bilaterally. Vertebral artery involvement options, which carry a higher morbidity and also occurs, although rarely in isolation from mortality. However, if considered in the appro- carotid disease. There is also a reported priate setting both in terms of patient suitabil- association between cerebrovascular FMD and ity and available expertise, they can be very intracranial “berry” aneurysms of an order of effective. around 7%. The symptoms of cerebrovascular Management of cerebrovascular FMD disease depend on the location and severity of depends on the presence or absence of symp- the lesions. toms to a certain extent. However, there is not a Where visceral vessels are affected,symptoms great deal of information on the progression of are usually due to ischemia. Infarction is rare the disease with which to make this judgment. due to the collateral arterial supply. In the In the asymptomatic setting, medical therapy is peripheral vascular tree, lesions at all levels have appropriate. In the presence of symptoms, intra- been identified. The commonest sites are the operative or percutaneous dilatation of lesions subclavian artery in the upper limb and the can be considered. external iliac artery in the lower limb. Where the visceral vessels are affected, surgi- Investigations are directed at ruling out other cal treatment may be indicated when medical causes of disease, but ultimately are based on therapy fails. Treatment of peripheral disease imaging of the affected arterial system. As a can broadly be considered as medical therapy, noninflammatory process, FMD is not associ- dilation therapy, either percutaneously or by ated with any of the acute-phase changes seen open technique, and surgical bypass or in the vasculitides, which can be detected by reconstruction. simple blood tests. Imaging can be either by noninvasive Cystic Adventitial Disease methods such as duplex scanning or magnetic resonance angiography (MRA), or by angio- This is a rare, nonatherosclerotic cause of limb graphy. The angiographic appearance of the claudication. Since being first reported in 1947, most common histological type of FMD is of a there have been less than 350 documented cases. string of beads. If duplex scanning is used to It affects people mostly in the fourth and fifth image the carotid system, it is important to decades, with a male to female ratio of 5:1. image as distally as possible in order not to miss Pathologically, it is defined by synovial- FMD, which in contrast to atherosclerotic like cysts in the adventitial layer of the arterial lesions is not commonly seen around the wall. These contain a mucinous gel that carotid bifurcation. contains various proportions of mucoproteins, Therapeutic intervention in FMD should be mucopolysaccharides, hyaluronic acid, and considered on an individual basis and depend hydroxyproline. Although the exact underlying on the individual as well as the location and etiology is unclear, a number of mechanisms severity of the disease. In renovascular disease, have been proposed. It has been suggested initial medical therapy for hypertension is that the fluid may come from the reactivation usually indicated. It should be remembered of mesenchymal cells trapped in developing 89

NONATHEROSCLEROTIC VASCULAR DISEASE vessels during embryological vessels. Another, images, demonstrating multiple intramural more widely supported hypothesis is that the cystic masses oriented along the long axis of the cysts develop from a herniation of adjacent vessel. synovium. This latter theory is backed up by There are numerous therapeutic options. imaging results and by the late age of onset of Spontaneous resolution of symptoms with disease. conservative management has been docu- From the reported cases, cystic adventitial mented. The cysts can also be drained percuta- disease has a predilection for the popliteal neously under computed tomography or artery above all others, but has also been ultrasound guidance. Surgical intervention con- described in the external iliac, axillary, and sists of either excision of the cysts and diseased distal brachial, radial, and ulnar arteries. In the wall with preservation of the artery or use of an acute setting the picture is of sudden onset and interposition graft. Both of these techniques progressive claudication. Physical examination have good initial results, although long-term may reveal a mass. Indeed, some of the cases are follow-up data are lacking. discovered in patients referred for investiga- Given the paucity of cases on which to base tions of a soft tissue mass, before the emergence interventional judgment, the decision is pro- of significant vascular symptoms. bably best made by considering the clinical The mainstay of investigation is imaging. urgency and available expertise. Although the main accepted method is angiog- raphy, good diagnostic results can also be obtained from less invasive techniques. Duplex ultrasonography can reveal the cystic disease References itself, which appears as anechoic or hypoechoic masses in the external wall. It also has the Dziadzio M, Denton CP, Smith R, et al. (1999) Arthritis Rheum 42:2646–55. advantage of providing information as to the Hoffman GS, Kerr GS, Leavitt RY, et al. (1992) Ann Intern degree of vascular impairment. Magnetic reso- Med 116:488–98. nance imaging also produces characteristic Ohta T, Shionoya S. (1988) Br J Surg 75:259–62. 9 Lower Limb Ischemia Rajabrata Sarkar and Alun H. Davies

Lower limb ischemia is an increasingly preva- Etiology and Presentation lent disorder that has a wide range of clinical presentations and variable consequences for Peripheral arterial occlusive disease due to ath- the patient. Although atherosclerosis is by far erosclerosis is the most common cause of lower the most common cause of lower extremity extremity ischemia in developed countries, with ischemia,a variety of other conditions can cause 3% to 6% of the population over the age of 65 either acute or chronic lower extremity suffering from symptomatic disease. The clini- ischemia. Three major factors are contributing cal presentation of long-standing ischemia can to an increase in both the prevalence and inci- be variable, with symptoms ranging from inter- dence of lower extremity ischemia. The first mittent claudication to rest pain, arterial ulcers, is the general aging of the population in devel- and frank gangrene. The classic progression of oped countries, with its attendant increase in symptoms in atherosclerotic lower extremity the prevalence of atherosclerosis, peripheral ischemia is (1) decreased pulses without any aneurysms, and other vascular lesions associ- symptoms, (2) intermittent claudication, (3) rest ated with advanced age. The second factor is the pain, and (4) arterial ulceration or gangrene alarming increase in the incidence of diabetes, (Fig. 9.1). Patients with limited ambulation due particularly among adolescents and younger to other causes (e.g.,stroke,musculoskeletal dis- adults.As diabetes accelerates the progression of orders) or diabetic neuropathy may present ini- atherosclerosis and lower extremity ischemia, tially with evidence of advanced ischemia such we can anticipate further increases in the as arterial ulceration or frank gangrene. Limb number of patients presenting at a younger age ischemia should always be considered in the with lower extremity ischemia. The third factor evaluation of the older patient who presents is the increasing numbers of patients who have with a nonhealing ulcer of the lower extremities, undergone prior peripheral arterial bypass or with an extensive or persistent skin or soft surgery and are potentially at risk for either tissue infection of the foot. graft occlusion or progression of disease. At Other causes of limb ischemia include many major medical centers the majority of embolic or thrombotic sequelae of aortic or patients presenting with acute limb ischemia peripheral aneurysms, embolization from the are those with thrombosis of a prior lower heart or proximal arterial sources, and arterial extremity arterial reconstruction. This chapter dissection (usually aortic). More unusual causes reviews the causes, clinical presentations, diag- include popliteal entrapment syndrome, ad- nostic approach, treatment options, and out- ventitial cystic disease, and Buerger’s disease comes of chronic and acute lower extremity (thromboarteritis obliterans). Some of these eti- ischemia. ologies such as embolization or thrombosis of

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Figure 9.1. Chronic limb ischemia, progression of disease. Atherosclerosis leads to arterial occlusion, resulting in loss of pulses fol- lowed by claudication.In patients with mild peripheral arterial disease,the best treatment option is risk factor modification and exer- cise.In more severe cases there is rest pain,which usually occurs at night followed by gangrene (photo insert) or ulceration.Rest pain and gangrene/ulceration are considered limb threatening ischemia and the surgical options are amputation or revascularization. Aggressive attempts at revascularization are usually undertaken in ambulatory patients.

an aneurysm present as acute limb ischemia, and this resolution occurs if the patient simply which is characterized by the 5 P’s: pulseless- stops and stands in place. Patients with neuro- ness, paralysis, paresthesia, poikilothermia genic claudication usually have to sit down to (coolness), and pallor. relieve their pain. Neurogenic claudication and musculoskeletal pain are often induced by standing in one place for prolonged periods Chronic Ischemia (waiting in line at the bank or washing dishes). This is not the case with vascular claudication, Patient History where lower extremity muscular oxygen demands are not as greatly increased by Patients are often referred for vascular evalua- standing as they are by prolonged walking. tion if they have reproducible pain in the lower Neurogenic claudication is relieved by leaning extremities with walking.Although many disor- forward, so patients with this disorder often ders can cause these symptoms, several basic note that they can lean forward onto a grocery questions can be asked to ascertain a vascular cart or lawn mower and go substantially further etiology. Patients with vascular claudication than they can walk unaided. Similarly, the always have pain when they walk a relatively patient with neurogenic claudication often can constant distance on level ground; they do not walk further on an incline, whereas vascular have variable days when they can walk for con- claudication is marked worsened if the patient siderably greater distances without pain. Often is on an incline. Patients with musculoskeletal patients know exactly how far or for how long disorders often have pain that is present at rest, they can walk before the symptoms occur. This or worsened by standing or sitting in certain is in contrast to patients with neurogenic clau- positions. The pain in neurogenic claudication dication or musculoskeletal causes of lower often is described as originating in the thigh extremity pain, where the symptoms occasion- and then extending down the leg, which is quite ally occur at rest or at with highly variable different from the focal posterior calf pain walking distances. Stopping results in resolution usually noted in vascular claudication. Together, of vascular claudication within a few minutes, these aspects of the history of the patient’s 93

LOWER LIMB ISCHEMIA symptoms help differentiate vascular from neu- History-taking in the patient with lower rogenic claudication. extremity ischemia should also focus on More pronounced ischemia results in pain at symptoms of atherosclerosis in other vascular rest, which also has specific features that distin- beds, particularly the cerebral and coronary guish it from the many other causes of lower circulation. Patients with symptomatic lower extremity pain. Ischemic rest pain occurs when extremity ischemia have a 20% to 60% in- the blood flow to the foot is decreased to the cidence of significant coronary artery disease, point where ischemia of the sensory nerves and the coexistence of cerebrovascular and occurs, hence the burning causalgia-like quality lower extremity arterial occlusive disease is also of the pain. Cardiac output decreases with sleep, well established. Symptoms of angina, conges- and most patients describe symptoms that are tive heart failure, and transient ischemic attacks initially present only at night. As the ischemia or strokes should be diligently investigated as becomes advanced, the pain is present con- many patients may ascribe these symptoms to a stantly. The more distal aspects of the lower nonvascular cause and may not volunteer this limb are the most ischemic, and rest pain is important information. The history should also most commonly described as occurring across include any prior events, such as blue or painful the metatarsal heads of the affected foot. toes, which may be suggestive of an embolic Ischemic pain awakens the patient from sleep cause of the ischemia. and is relieved by dangling the affected limb over the edge of the bed, which patients quickly Physical Examination learn will allow uninterrupted sleep. Alterna- tively patients awakened by the pain find that The physical examination should be complete rubbing the foot or walking to stimulate circu- and focused on the detection of occlusive and lation relieves the pain. Dangling (or standing) aneurysmal disease throughout the peripheral causes the perfusion pressure of the foot to be circulation.The presence (or absence) of carotid augmented by the hydraulic pressure due to the bruits, cardiac arrhythmias, peripheral pulses, gravity component of the height of the calf. and bruits should be documented, and any prior This is approximately 40cm of water pressure scars consistent with arterial bypass surgery (length of the calf), which equals a 29mmHg or vein harvest should be noted. This is of par- augmentation of foot perfusion pressure. ticular importance when planning reoperative This increase is enough to overcome the critical infrainguinal bypass surgery, which may involve closing pressure (CCP) of the precapillary harvesting autogenous vein from multiple sphincter in the vascular bed and restore flow to sites and limbs. The stigmata of chronic occlu- the ischemic regions of the foot. With progres- sive or embolic disease should be diligently sion of disease and more pronounced ischemia, sought, including muscle atrophy, loss of sec- this maneuver no longer provides relief as the ondary skin structures such as hair and nails, net pressure falls below the CCP and capillary dependent rubor, splinter hemorrhages, and perfusion ceases. Several other disorders cause embolic skin lesions or dusky toes. Nonpalpable lower extremity pain at night and can be pulses should be interrogated with a handheld confused with ischemic rest pain. Diabetic leg Doppler, and a bedside ankle—brachial index cramps are quite common and occur at night, (ABI) determined with an inflatable blood pres- but the site of pain is variable and the pain often sure cuff placed above the site of the Doppler migrates up or down the leg. Musculoskeletal signal and then at the wrist. Peripheral and pain rarely occurs in the midfoot at night, and aortic aneurysms may be difficult to detect on is usually localized to the joint in question physical examination, particularly in the obese (commonly the ankle or knee). Musculoskeletal patient.A wide or easily palpable popliteal pulse causes of foot pain are usually exacerbated by is suspicious for a popliteal aneurysm, and eval- walking or standing and relieved by rest, in con- uation with ultrasound or computed tomogra- trast to ischemic pain. Infections in the foot, phy (CT) scanning is indicated to determine the particularly osteomyelitis, can cause constant true diameter of the vessel. pain at rest but are often easily recognized due More advanced limb ischemia may be asso- to other . ciated with arterial ulcers or frank gangrene. 94

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Arterial ulcers are distinguished from venous the aorta and femoral and popliteal arteries ulcers by their location on the more distal should be performed. aspects of the foot, and their exquisite sensitiv- ity to touch. They appear as small, dry,punched- Diagnostic Studies out lesions in the skin, and have often been present for long periods of time without evi- The history and physical examination generally dence of granulation tissue or scar contracture facilitate classification of the degree of arterial at the edges. Larger ulceration located at the insufficiency. Diagnostic studies are indicated ankle, particularly if moist or weeping, is more when the diagnosis is in question, or in prepa- characteristic of venous disease, although ration for intervention. Noninvasive vascular patients with combined arterial and venous testing is also useful in establishing the degree insufficiency may present with long-standing of ischemia when there are other confounding ankle ulceration that fails to heal despite factors present, such as venous disease, diabetic aggressive treatment of venous insufficiency. foot ulcers, or active infection. Usually the ABI All patients with presumed venous ulceration facilitates accurate determination of the degree should undergo examination of peripheral of limb ischemia; however, several conditions pulses, and if not present, prompt evaluation for exist in which the ABI and segmental pressures arterial ischemia and consideration for revascu- may be falsely elevated. These include diabetes, larization. Even moderate degrees of arterial chronic renal failure, and advanced age (over 80 insufficiency in conjunction with venous years), which can cause calcification of the insufficiency may result in failure of a primarily medial layer of the arterial wall, which in turn to heal.Similarly,moderate arterial causes incompressibility and subsequent false occlusive disease (ABI 0.4 to 0.5), which ordi- elevation of any cuff-based determination of narily does not cause tissue loss, may cause a peripheral perfusion pressure.An ABI of greater surgical incision in the lower extremity not to than 0.9 is associated with a readily palpable heal in a timely fashion. This is most commonly pulse, and the absence of a pulse with such an seen after harvest of the lower aspect of the ABI value is evidence of incompressibility. In greater saphenous vein for coronary artery these cases several alternatives can be used to bypass surgery, but can occur after orthopedic establish the diagnosis of arterial ischemia. A or podiatric surgery in the lower limb. toe cuff can be used to determine a toe— Gangrene of a toe may be produced by brachial index (TBI), as the medial calcification advanced ischemia alone, or can be secondary rarely extends into the vessels of the foot. The to infection, particularly in diabetic patients. If waveform tracings from the pulse volume associated with infection, the infectious process recorder are not altered by vessel calcification, often extends further into the forefoot than the and examination of the contour of these wave- extent of cutaneous changes. Less frequently a forms at the various arterial levels can suggest patient presents with isolated toe gangrene or the site of the occlusive lesions. Flattened wave- pregangrenous changes (blue toe) without evi- forms at the ankle or more distal level or a TBI dence of either infection or advanced ischemia less than 0.6 is an indication of arterial insuffi- of the limb. This scenario, particularly if present ciency. More sophisticated diagnostic measures in more than one toe, and especially if found in such as transcutaneous oxygen measurement nonadjacent toes, is suspicious for embolic are sometimes useful to determine perfusion disease, or so-called blue-toe syndrome. If the in the foot of patients with confounding involved toes are on both feet, then an embolic factors such as lymphedema or severe venous source proximal to the aortic bifurcation is the insufficiency. cause. All patients with evidence of chronic Exercise testing plays an important role in the peripheral embolization should undergo subset of patients with symptoms of early occlu- echocardiography and complete angiography of sive disease despite relatively normal perfusion the thoracic and abdominal aorta, ileofemoral at rest. Increasing lower extremity blood flow by system, and proximal aspect of the involved treadmill testing can accentuate the gradient limbs. Embolic sources can include proximal across a moderate stenosis and demonstrate a aneurysms, which may not be readily detectable drop in distal perfusion pressures after exercise by angiography, and ultrasound examination of that is not present at rest. This is based on 95

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Poiseuille’s law where the pressure drop across cardiac disease and cerebrovascular disease, a stenosis is directly proportional to the volume which are both responsive to reduction of the flow across the lesion. Patients with a normal same causative risk factors as lower extremity ABI at rest and a decreased ABI after exercise ischemia. An important risk factor reduction is testing are uncommon and almost always cessation of tobacco use, and management of have aortoiliac occlusive disease. Many patients dyslipidemia, diabetes, and hypertension also cannot complete exercise testing on a treadmill plays a role. A critical factor is reassurance to because of angina or pulmonary dysfunction; patients and their family that disease progres- however, a normal ABI after exercise testing sion to critical limb ischemia and possible excludes arterial insufficiency as a cause of amputation, which is many patients’ greatest lower extremity pain with walking. fear, is unlikely, particularly with cessation of Imaging studies of the aorta and lower further tobacco use. The 10-year risk of limb extremity arteries are not necessary to deter- loss with claudication is less than 10%, and mine the presence or extent of arterial often simply alleviating this fear is the most insufficiency and are thus reserved for planning valuable aspect of evaluation and treatment of interventions to revascularize the lower extrem- mild to moderate limb ischemia. ity. The most widely used study is contrast A wide range of pharmacological agents angiography, although duplex scanning and and alternative therapies have been utilized to magnetic resonance angiography are less inva- treat the symptoms of mild to moderate limb sive modalities that can provide images that can ischemia. Unfortunately, controlled clinical obviate the need for conventional angiography. trials coupled with careful evaluation of long- These are utilized in patients with documented term improvement have demonstrated a consis- adverse reactions to contrast agents, or with tent lack of benefit for the vast majority of renal insufficiency that increases their risk of agents tested. This includes vasodilator drugs, contrast-induced nephropathy.In most patients, pentoxifylline, antiplatelet and antithrombotic contrast angiography provides the most de- drugs, chelation therapy, and a variety of herbal tailed information to direct catheter-based or medications such as gingko. The agents that surgical limb revascularization. Other imaging have been shown to be of some value in con- modalities that play a lesser role in the evalua- trolled clinical trials include cilostazol, a phos- tion of limb ischemia include CT scans and phodiesterase inhibitor that cannot be used in ultrasound studies to determine the presence patients with cardiac dysfunction, the Tibetan of aortic and peripheral aneurysms (especially herbal supplement Padma Basic, and high doses as sources of emboli), echocardiography to of L-arginine, the amino acid precursor of evaluate potential cardiac embolic sources, and the endogenous vasodilator nitric oxide. The duplex evaluation of veins preoperatively for benefit in walking distance with these agents, use as bypass conduits. although statistically significant in clinical trials, is often minimal in terms of functional Treatment improvement for the patient. For example in a randomized multicenter trial, the mean walking Mild to moderate limb ischemia that does distances after 4 weeks of either cilostazol or not warrant invasive revascularization can be placebo were 306 versus 267m (Money et al., followed with serial examinations. An ABI 1998). It is unclear whether these minimal determination is obtained at the initial visit to increases represent a meaningful improvement establish a baseline, as this measure may over a graduated exercise program alone. improve with exercise or deteriorate with pro- Studies of graded exercise programs have gression of disease. The emphasis in treatment demonstrated that motivated patients can of these patients is on risk factor modification double their walking distance; however, this to prevent progression of disease and con- requires walking to near-maximal pain levels currently increase longevity, and a walking for 30 minutes on a regular basis for at least 6 program to encourage exercise and increase months (Gardner and Poehlman, 1995). exercise tolerance. The most common causes of Many patients with moderate chronic limb death in patients with symptoms of lower ischemia have symptoms that they consider dis- extremity arterial insufficiency are ischemic abling, and seek revascularization to increase 96

VASCULAR SURGERY their ability to exercise or perform job-related Table 9.1. Conduits for revascularization tasks. The role of revascularization, whether Axillofemoral, aortofemoral, Dacron or ePTFE catheter-based or surgical, in patients with femoral–femoral claudication remains controversial. Factors that Femoral: above the knee Autologous vein, should be considered include ongoing cigarette Dacron, or PTFE use, the patient’s commitment to exercise and physical activity, and the anatomical level of Femoral: below the knee Autologous vein occlusive disease that requires correction. Aor- PTFE, polytetrafluoroethylene; ePTFE, expanded PTFE. toiliac occlusive disease, as judged by physical examination and noninvasive studies, can be treated well by angioplasty and stenting with minimal risk to the patient. More extensive disease, particularly involving either the patency (Veith et al., 1986). A randomized mul- infrarenal aorta or the external iliac arteries, is ticenter trial demonstrated an improved graft better treated with aortobifemoral bypass graft- patency and decreased risk of subsequent ing. The long-term results of aortobifemoral amputation with heparin-bonded Dacron grafts bypass grafting are excellent, with patencies in comparison to polytetrafluoroethylene exceeding 90% at 5 years. Although aortoiliac (PTFE) grafts (Devine et al., 2001), and repre- endarterectomy was the first procedure devel- sents the first major advance in synthetic vas- oped for the treatment of occlusive disease of cular grafts that has been shown to improve these vessels, it has largely been replaced by clinical results relative to standard materials. bypass grafting. Extensive unilateral disease, Self-expanding and balloon-expandable stents particularly occlusion of the external iliac in conjunction with balloon angioplasty are artery, can often be treated with femoral– being applied to stenoses and occlusions of the femoral bypass grafting. This is a procedure of distal superficial femoral artery with improving substantially smaller magnitude than an aorto- results, and are extending the ability to provide bifemoral bypass, and is often the procedure of percutaneous revascularization of moderate choice in patients with coexisting cardiac and lower limb ischemia. pulmonary disease. Femoral–femoral bypass Occlusive disease of the popliteal artery or requires normal flow in the contralateral ile- more distal vessels, although uncommon in the ofemoral system, and mild to moderate disease nondiabetic patient with claudication, requires of the contralateral artery can be treated with bypass with autogenous vein to the distal angioplasty and stenting to obtain sufficient popliteal artery or tibial vessels. These proce- inflow to support the femoral–femoral bypass dures are generally reserved for more severe graft. Although some centers have advocated ischemia where salvage of the extremity is in axillofemoral bypass grafts for mild to question. If there is calf claudication with exten- moderate limb ischemia and claudication, our sive occlusive disease of the proximal aspects of policy is to reserve this form of extensive extra- the tibial arteries, a femoral-tibial bypass to a anatomical bypass for poor-risk patients with distal vessel may result in excellent perfusion of limb-threatening ischemia or when revascular- the foot with minimal relief of claudication. ization is required after removal of infected This is due to the lack of retrograde perfusion aortic grafts. to the geniculate arteries that supply the major Occlusive disease of the distal superficial muscles of the upper calf. femoral artery, another common site in mild More advanced ischemia of the lower limb to moderate limb ischemia, generally requires generally requires a more aggressive approach bypass with either prosthetic or autologous to revascularization if long-term viability of the grafts (Table 9.1). Femoral-popliteal bypass limb is to be preserved. The need for revascu- grafting is often performed with excellent larization needs to be combined with a complete results in patients with disabling claudication. evaluation of the medical and functional status A randomized prospective trial of prosthetic of the patient. Patients with critical limb versus greater saphenous vein bypass grafts ischemia, which presents with rest pain, arterial in the femoral to above-knee popliteal artery ulcers, or frank gangrene, commonly have mul- did not demonstrate a difference in long-term tilevel occlusive disease, which usually requires 97

LOWER LIMB ISCHEMIA major surgical revascularization to achieve choices for conduit include cryopreserved long-term limb salvage. They also have corre- cadaver saphenous vein, umbilical vein grafts, spondingly more advanced atherosclerosis in conventional prosthetic grafts (PTFE and their coronary and cerebrovascular circulation, Dacron), and heparin-bonded Dacron. These and their perioperative morbidity and mortal- have variable patency rates, all of which are infe- ity is higher than for patients with claudication. rior to saphenous vein or spliced autologous The incidence of renal insufficiency or chronic veins when utilized for femoral-tibial bypass. failure as well as diabetes is higher in patients A useful technique in patients with limited who present with signs of critical limb ischemia, amounts of available vein is to originate the and these medical factors have been noted in graft from a more distal site than the common several multivariate analyses to be independent femoral artery, thus requiring shorter segment predictors of poor outcomes and higher mor- of vein conduit. Long-term patency is not com- tality after arterial reconstruction. promised by originating the graft from the deep Revascularization in patients with critical femoral artery, the superficial femoral artery, or limb ischemia often requires correction of the popliteal artery provided that there is not both aortoiliac and infrainguinal (femoral- significant occlusive disease above the inflow popliteal-tibial) occlusive disease. In patients site (Wengerter et al., 1992). Autogenous vein who present with advanced tissue loss or gan- grafts should be studied postoperatively along grene and multilevel occlusive disease, restora- their entire length periodically with duplex tion of in-line arterial flow to the foot is ultrasound to identify potential areas of mid- required to heal the large tissue defects. A com- graft stenosis, which should be corrected with bination of percutaneous treatment of the aor- either balloon angioplasty or surgical repair toiliac disease (if anatomically suitable) with before graft thrombosis occurs. femoral-popliteal or femoral-tibial bypass can Many patients with critical limb ischemia be used to rapidly restore foot perfusion in are bedridden or do not ambulate because of these cases. If the presenting ischemic symp- neurological or musculoskeletal problems. In toms are rest pain or small arterial ulcers, then these patients, primary amputation is a safer correction of one level of occlusive disease and more expeditious means of dealing with (usually the aortoiliac) with angioplasty/stent- foot gangrene than surgery for revasculariza- ing or surgical bypass relieves the symptoms. tion. The level of amputation, which is always The conduit of choice for femoral-tibial of great patient concern even when ambula- bypass, or femoral-popliteal bypass with poor tion is not an issue, is determined by the ambu- runoff is the greater saphenous vein (Table 9.1). lation potential of the patient and the degree Prospective studies comparing reversed versus of perfusion required to heal the amputation. in situ saphenous vein grafts have not demon- Although there are numerous guidelines and strated a difference in patency or limb salvage means of measuring skin perfusion to deter- rates between the two techniques (Harris et al., mine the appropriate level of amputation, 1987). In many patients with critical limb clinical judgment remains the final factor. ischemia, the ipsilateral greater saphenous vein Enthusiasm for various quantitative means of is not available for use as a conduit due to prior measuring limb and skin blood flow has been harvest or . If the contralateral tempered by prospective studies of these greater saphenous vein is not available, then various techniques, which have failed to identify secondary sources of autogenous vein such as one quantitative test that preoperatively esti- the lesser saphenous vein or arm veins should mates probability of healing with sufficient be preoperatively mapped by duplex scanning positive and negative predictive value. Transcu- and utilized. The use of spliced segments of taneous oxygen testing (TcPO2) is the most autologous vein was recently compared to PTFE readily available of these sophisticated blood grafts with vein cuffs in a randomized prospec- flow measurements, which include radiolabeled tive trial of patients without an available greater xenon washout, laser Doppler velocimetry, and saphenous vein (Kreienberg et al., 2002). photoplethysmography perfusion studies. A Patency was greater in the spliced arm vein TcPO2 of greater than 40mmHg at the level of group (87% vs. 59% at 2 years) with similar rates proposed amputation is predictive of healing, of limb salvage (94% and 85%). Alternative and a TcPO2 of less than 20mmHg is indicative 98

VASCULAR SURGERY of a high likelihood of failure to heal. Unfortu- genesis) has spurred interest in applying angio- nately, many patients with lower extremity genic therapy to patients with limb ischemia. ischemia fall into the range of 20 to 40mmHg, Preliminary results with growth factors such where clinical judgment must be used to decide as fibroblast growth factor are encouraging on the level of amputation. (Lederman et al., 2002), and further studies are We recommend attempting a below-knee needed to define the optimal growth factor, amputation in any ambulatory patient with rea- route of delivery, and duration of therapy. Sim- sonable rehabilitation potential in whom there ilarly, the finding that circulating bone is detectable popliteal artery Doppler signal. marrow—derived stem cells contribute to the This approach is based on the known benefits angiogenesis and spontaneous revasculariza- with preservation of the knee joint for ambula- tion seen in experimental hindlimb ischemia tion, and will predictably result in a small has led to trials of stem cell therapy for the treat- number of failures that require revision as a cost ment of chronic limb ischemia in humans, with of salvaging as many below-knee amputations promising preliminary results (Tateishi-Yuyama as possible. In the nonambulatory patient with et al., 2002). These areas of investigation should advanced ischemia, a primary above-knee lead to therapies for critical limb ischemia that operation is performed if perfusion at the level will complement surgical revascularization and of the popliteal artery is poor or nondetectable. extend our ability to provide limb salvage. Although there is some benefit to preservation of the knee joint even in the nonambulatory patient for aid in transferring from bed, major Acute Ischemia amputations in this population carry at least a 10% to 15% mortality per procedure and it is Patient History recommended to perform a single definitive above-knee procedure if there is questionable The most important determination in the eval- perfusion in a nonambulatory patient. uation of acute limb ischemia is whether the ischemia is due to an arterial embolus or throm- Outcomes bosis of a chronically diseased artery. Two aspects of the patient’s history contribute to this There has been a steady improvement in limb decision. The first is the onset of symptoms. salvage rates due to refinements in both percu- Embolic occlusion of a normal arterial bed taneous and surgical revascularization for results in sudden onset of symptoms, and the chronic limb ischemia. In particular, the wide- patient can often recollect the exact moment of spread application of femoral-tibial bypass onset of the ischemia. In contrast, thrombotic has led to revascularization of limbs that until occlusion of a diseased native artery occurs recently would have been deemed inoperable. more gradually, with symptoms often worsen- Awareness of limb ischemia as a cause of non- ing over several days. The second important healing ulcers and patient and practitioner edu- aspect of the history is the presence or absence cation are responsible for earlier evaluation and of chronic peripheral arterial occlusive disease, referral of patients for revascularization. The which is more frequently associated with success of aortoiliac angioplasty and stenting thrombosis rather than embolism. Thus the has led to relief of claudication in patients presence of previous symptoms such as claudi- without the morbidity and length of hospital stay cation or rest pain, or a history of prior previously associated with aortofemoral bypass. interventions for peripheral arterial occlusive Despite the advances in percutaneous and disease, strongly suggests that the acute surgical revascularization, a large number of ischemia is secondary to thrombosis of a dis- patients with critical limb ischemia will eventu- eased vessel or bypass graft. Many of these ally undergo an amputation (>50,000 cases per patients have an antecedent history of acute year in the United States). Many patients are dehydration from gastrointestinal causes or not candidates for standard revascularization poor perfusion, from acute cardiac dysfunction. techniques because of anatomical or medical Conversely a lack of prior claudication coupled factors. The discovery that endogenous peptides with the presence of risk factors for arterial can induce growth of new blood vessels (angio- embolization (atrial fibrillation, a recent 99

LOWER LIMB ISCHEMIA myocardial infarction, dilated cardiomyopathy, of whether the occlusion is due to embolism or prior embolic event) is more consistent with or thrombosis of a diseased artery, as this dis- either arterial embolization or another unusual tinction leads to either immediate surgical nonatherosclerotic cause of acute ischemia such or preoperative angiography to as dissection or thrombosis of a peripheral delineate the cause of ischemia. The arteries of aneurysm. Unfortunately, this maxim cannot the lower extremity have tremendous capacity always be relied on, as up to 25% of patients for collateral flow, and thus thrombosis of a with embolism as a cause of acute limb ischemia native artery occurs only when atherosclerotic have long-standing signs and symptoms of lesions are very advanced. Such advanced ath- prior peripheral arterial occlusive disease. erosclerosis is usually symmetrical,and the con- tralateral limb does not have a normal pulse exam. The presence of normal pulses in the Physical Examination contralateral limb is highly suggestive of an embolism as a cause of acute ischemia, and Acute limb ischemia is characterized by the five warrants operative embolectomy without the P’s: pulselessness, paralysis, paresthesia, pain, delay associated with preoperative angiography. and pallor. The level of arterial occlusion is gen- Unfortunately, the converse is not always true, erally one anatomical level higher that the clin- as signs and symptoms of prior peripheral ical manifestation of the ischemia.Thus patients arterial occlusive disease do not guarantee with an embolus lodged in the proximal superfi- that the acute ischemia is due to thrombosis cial femoral artery present with an ischemic rather than embolism. Thus the presence of calf. The severity of the ischemia can be deter- significant peripheral arterial occlusive disease mined from the physical findings, with pain and (defined by both prior symptoms or physical pallor occurring early and paresthesia and findings in the contralateral limb) in patients paralysis being later findings. Paresthesia is due with acute limb ischemia is an indication for to direct ischemia of the sensory nerves within angiography. Angiography definitively identi- the extremity and is often reversed with prompt fies the cause of the acute ischemia and delin- revascularization. Paralysis can be due to either eates the proximal and distal arterial anatomy ischemia of the motor neurons or muscle death. should a bypass be required either immediately Muscle death can be determined on examina- or subsequently to relieve ischemia. Nonem- tion by rigidity of the ischemic muscle to pal- bolic causes of acute ischemia include pation (rigor) and corresponding difficulty thrombosis of a chronically diseased vessel, moving the joints with passive motion. If skele- thrombosis of a previous bypass graft, throm- tal muscle death has occurred, there is little to bosis of a peripheral aneurysm (particularly a no chance for meaningful limb salvage. popliteal aneurysm), and proximal arterial dis- A major problem with diagnosis of acute section (usually aortic). The treatment of these limb ischemia remains the failure to consider conditions is quite varied, and immediate surgi- ischemia as a cause of acute symptoms in the cal exploration without angiography is often limb,leading to delays in treatment that can lead unsuccessful in restoring flow. In many cases, to limb loss. These delays are usually seen in angiography is not only diagnostic but is thera- patients without known prior peripheral vascu- peutic in terms of initiating thrombolytic lar disease, such as those with undiagnosed therapy for occlusion of bypass grafts or throm- popliteal aneurysms, aortic dissection, or bosed popliteal artery aneurysms. Aside from (most commonly) arterial embolism. The most assessment of limb perfusion by Doppler exam- common misdiagnosis is a primary neurologi- ination, immediate angiography is the only cal problem, such as spinal cord impairment or diagnostic study utilized in the evaluation of stroke, to which the paresthesia and paralysis of acute limb ischemia. ischemia is attributed. Treatment Diagnostic Studies For any form of acute limb ischemia, systemic The history and physical examination in acute anticoagulation with intravenous unfraction- limb ischemia are focused on the critical issue ated heparin is immediately instituted while 100

VASCULAR SURGERY preparations are made for surgery or angiogra- ill with concurrent renal, mesenteric, or spinal phy. Patients with known sensitivity to heparin cord ischemia. Mortality rates approaching 40% or a documented history of heparin-induced have been reported from major centers in thrombocytopenia can be treated with direct patients with coexisting cardiac and renal thrombin inhibitors. Anticoagulation alone disease. Advances in catheter-directed therapy usually does not relieve the ischemia, but it for acute dissection are allowing rapid restora- helps prevent further propagation of the throm- tion of perfusion to the involved branches of the bus and preserve flow in collateral vessels aorta without the physiological stress of opera- around the occlusive thrombus. The specific tive repair of the thoracoabdominal aorta treatment of acute limb ischemia rests on pre- (Slonim et al., 1996). These procedures include operative establishment of the cause of the acute endovascular stenting of dissections within the ischemia. In a patient with a prior history of thoracic aorta and catheter-based percutaneous peripheral bypass surgery, the most common fenestration to restore perfusion to both false cause of acute limb ischemia is thrombotic and true aortic lumina. occlusion of the bypass graft. In these patients, For limb ischemia secondary to suspected as well as patients with preexisting chronic femoral, iliac, or aortic bifurcation emboli, peripheral vascular occlusive disease, preopera- embolectomy is performed via the common tive angiography is usually obtained to deter- femoral artery. For bilateral limb ischemia mine the location of the occlusion and the where the embolus is lodged in the aortic bifur- inflow and outflow sites for bypass grafting. Pre- cation, bilateral transfemoral embolectomy is operative angiography is not utilized in those performed. Catheter embolectomy should be cases of advanced acute ischemia where the performed both proximally and distally from location of the problem is clinically obvious, the common femoral artery. This is usually per- such as a patient with a prior aortobifemoral formed through a transverse in the bypass graft, an absent femoral pulse, and a pro- common femoral artery placed opposite the foundly ischemic limb. The delay associated orifice of the deep femoral artery to facilitate with obtaining preoperative angiography is also passage of the catheter into both the superficial avoided in patients with suspected arterial and deep femoral arteries. The first priority embolism, which is treated with emergent should be establishment of adequate inflow to catheter embolectomy. the common femoral artery. This is usually Restoration of a functional and viable intact accomplished easily with catheter embolectomy, limb is extremely rare when skeletal muscle but occasionally the arterial flow from the exter- death has already occurred. If physical exami- nal iliac artery may be unsatisfactory even after nation suggests that limb paralysis is due to removal of all possible thrombus. This is usually death of the skeletal muscle, then the status of due to preexisting chronic occlusive disease the muscle is determined by operative explo- of the iliac arteries, but can also be caused ration. The high likelihood of amputation is dis- by dissection of a diseased vessel during the cussed with the patient and family members embolectomy. There are two options to manage prior to surgery,and primary amputation is per- inadequate inflow after transfemoral em- formed if there is no bleeding from the muscle bolectomy. The traditional solution is surgical and no muscle contraction with direct electrical bypass, usually with a femoral–femoral or stimulation.Aortoiliac revascularization may be axillofemoral graft. More recently, intraopera- subsequently required to obtain adequate blood tive angioplasty and stenting of the iliac system flow to allow healing of the definitive amputa- can be used to treat occlusive disease or dissec- tion site. tion of the ipsilateral iliac arteries. This can be Treatment of lower limb ischemia secondary performed via either an ipsilateral retrograde to aortic dissection can be either directed at cor- approach or the contralateral femoral artery. recting the dissection or an extra-anatomical The use of angioplasty and stenting in this bypass to relieve the limb ischemia. Correction setting can often restore adequate inflow more of the underlying dissection may require rapidly than constructing an extra-anatomical surgical repair of the thoracoabdominal aorta, bypass, and is the procedure of choice if although these procedures are formidable the appropriate expertise and equipment are undertakings in patients who are often critically available. 101

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Caution must be taken when restoring blood angiography is performed to determine the flow to the severely ischemic limb, as the stag- location and amount of residual thrombus. If nant and ischemic venous blood contains toxic thrombus is found in the proximal aspects of the metabolites from the limb. Sudden return individual tibial arteries and blood flow to the into the systemic circulation can be associated remains poor, then more distal embolectomy is with serious complications including acido- performed to restore blood flow to the foot. This sis, cardiac arrhythmias, or arrest and renal is usually performed via the infrageniculate damage. Release of the venous return from the popliteal artery, which is exposed via a medial ischemic limb to the body is done in close incision down distally to the tibioperoneal cooperation with the anesthesiologists, and trunk in order to allow the passage of the administration of antiarrhythmic agents, embolectomy catheter into each of the tibial sodium bicarbonate, and mannitol may be vessels. If the infrageniculate popliteal artery is required. In patients with prolonged ischemia, small or diseased, a longitudinal arteriotomy is particularly those with preexisting cardiac dys- closed after embolectomy with a small vein function, consideration is given to draining the patch; otherwise a transverse arteriotomy can initial venous return from the limb to prevent be primarily closed with interrupted sutures. flow of these toxic metabolites back to the cir- Irrigation of the distal circulation with culation of a compromised patient. The com- heparinized saline containing papaverine helps mon femoral vein is encircled at the level of the relieve spasm of the tibial vessels induced by inguinal ligament with a Rummel tourniquet passage of the embolectomy catheter. Intra- and the first 300 to 600mL of venous blood is operative instillation of thrombolytic therapy, exsanguinated via a transverse venotomy at the usually urokinase or streptokinase, has been time that arterial inflow to the limb is restored. described as a means of treating residual Appropriate replacement with banked blood is thrombus that cannot be retrieved by catheter essential to maintain adequate cardiac output embolectomy. Dramatic increases in patency of and oxygen delivery, and should be done con- the distal circulation have been noted after currently with the venous drainage. intraoperative thrombolytic therapy, and this Most emboli of cardiac origin lodge in the technique is particularly useful when there common femoral or proximal superficial fe- appears to be insufficient runoff to maintain moral artery. Smaller emboli may lodge in the patency of either a distal bypass graft or the popliteal artery, and embolic occlusion of indi- native proximal popliteal artery. vidual tibial arteries from a cardiac source is Arterial bypass plays an important role in the unusual. Once adequate inflow to the common management of acute limb ischemia, particu- femoral artery is established as described above, larly in patients with ischemia secondary to the embolectomy catheter is directed distally thrombosed popliteal artery aneurysms, arte- down the superficial femoral artery to retrieve rial dissection of the ileofemoral arteries, or distal thromboemboli. Restoration of back- thrombosis of a chronically diseased aortoiliac bleeding from the superficial femoral artery is segment. Bypass operations for acute occlusion followed by embolectomy of the profunda of the aortoiliac segment include aortofemoral femoris artery, which is rarely the site of bypass, femoral–femoral bypass, and axillo- embolization. Propagation of a secondary femoral bypass. The latter two are less extensive thrombus, however, does occur in the proximal procedures that are particularly useful in the aspect of this vessel, although more distal seg- emergent management of acute aortoiliac ments remain patent due to collateral circula- thrombosis secondary to acute medical illness tion via the numerous branches. Transfemoral such as cardiogenic shock.The femoral–femoral embolectomy of the distal circulation may bypass is performed for acute unilateral sometimes not result in restoration of a satis- ischemia if embolectomy fails to restore ade- factory Doppler signal at the level of the ankle. quate inflow or if the acute ischemia is due to There may be subsequent propagation of any nonembolic cause. A clinically normal con- thrombus distally into tibial vessels, or frag- tralateral femoral pulse is a prerequisite for a ments of more proximal emboli may become femoral–femoral bypass graft, and a decreased dislodged into the distal circulation during contralateral pulse would favor the placement of catheter embolectomy. In this case on-table an axillofemoral bypass or aortofemoral bypass 102

VASCULAR SURGERY in the patient whose medical condition will Table 9.2. Controversies in the management of limb ischemia tolerate it. Emergent axillofemoral bypass and Primary amputation versus complex bypass for limb aortofemoral bypass are also used to treat bilat- salvage in patients with critical limb ischemia and eral acute limb ischemia. Axillofemoral bypass renal failure and diabetes is applied in the unstable or critically ill patient Thrombolytic therapy versus surgical thrombectomy in whom the more extensive incisions, pro- for aortofemoral graft occlusion. longed time to revascularization, and greater Thrombolytic therapy versus surgical therapy for fluid shifts associated with aortofemoral bypass primary aortoiliac thrombosis. may be detrimental. Emergent aortofemoral bypass for acute ischemia has the advantage of providing definitive revascularization from the most reliable source of inflow, namely the of attempted bypass surgery to a distal vessel nondiseased juxtarenal aorta. The disadvantage not angiographically visualized below the level of urgent or emergent aortofemoral bypass is of acute thrombosis. Accordingly, we utilize the substantial magnitude and duration of an thrombolytic therapy even in the presence of aortic procedure in a potentially ill or medically early neuromuscular changes if there are no unstable patient with insufficient time for pre- vessels visualized initially that are suitable operative optimization of associated medical targets for bypass grafting (Table 9.2). Although conditions. thrombolytic therapy is usually associated with Infrainguinal bypass procedures are also improvement in the acute ischemia,serial exam- commonly used in the management of acute ination of these patients for worsening ischemia limb ischemia. Thrombosis of a popliteal artery is critical to determine if thrombolytic therapy aneurysm or a diseased popliteal artery is a should be terminated and surgical bypass typical indication, as are symptomatic acute performed. thrombosis of the superficial femoral artery The conduit of choice for infrainguinal and dissections extending more distal to the bypass to treat acute limb ischemia is the common femoral artery. Acute thrombosis of a greater saphenous vein, either from the involved popliteal artery aneurysm or diseased popliteal limb or if necessary from the contralateral leg. artery can be successfully treated with popliteal There is usually insufficient time for preopera- or tibial bypass only if a patent target vessel tive vein mapping in such patients, and the suit- below the popliteal artery is identified on pre- ability of the saphenous vein is defined by operative angiography. Although some authors operative exploration if there are no signs of have advocated bypass to isolated or “blind” prior harvest. If there is no available saphenous segments of the popliteal or tibial arteries, we vein, which is often the case in patients with prefer to utilize target vessels that flow across acute ischemia secondary to thrombosis of a the ankle joint to supply the pedal arch, or in the prior saphenous vein graft, then a prosthetic case of the peroneal artery, collateralize via the (usually PTFE) graft with a vein patch or cuff or anterior or posterior branch at the malleolus to a cryopreserved cadaver vein can be used. Both provide flow to either the anterior tibial or pos- of these options are associated with substan- terior tibial artery that subsequently supplies tially worse long-term patency than autologous the foot. Failure to visualize any target vessel saphenous vein, particularly when used for in the calf below the level of acute thrombosis bypass to the below-knee popliteal artery or is an indication for intraarterial thrombolytic tibial arteries. therapy to improve the outflow and provide a After revascularization for acute limb suitable target for a subsequent bypass graft. ischemia, consideration is given to immediate Neurological changes secondary to acute fasciotomy if the ischemia was severe and of ischemia are traditionally considered con- greater than 4 to 6 hours’ duration. Immediate traindications for thrombolytic therapy due to prophylactic fasciotomy avoids problems with the time required for effective thrombolysis. identifying compartment syndrome subse- However, the results with thrombolytic therapy quently in patients who are receiving pain med- for moderate to severe acute ischemia (particu- ication or sedation and already have pain in the larly thrombosed popliteal aneurysms) are limb from the surgical incisions (particularly if substantially better than the dismal outcomes the popliteal artery was exposed below the 103

LOWER LIMB ISCHEMIA knee). The need for fasciotomy is less common weeks associated with healing open wounds by in patients with preexisting arterial insuffi- secondary intention. If there is a question of ciency, as they possess preformed arterial col- whether the edema will compromise skin lateral pathways that decrease the degree of closure, we place interrupted nylon horizontal acute ischemia induced by the superimposed mattress sutures in the skin and leave them thrombosis or embolus. Nonetheless, either untied at the time of fasciotomy. Once the immediate fasciotomy or careful observation for edema subsides (usually 1 to 3 days), delayed development of elevated compartment pres- primary closure is accomplished by tightening sures is mandatory following any prolonged and tying these sutures at the bedside under period of ischemia of the lower extremity. This intravenous sedation. The muscle ischemia in is particularly true in patients with thrombosis compartment syndrome results in myoglobine- of an aortobifemoral bypass limb with poor mia and myoglobinuria, and precautionary outflow, as profound ischemia is produced when measures to protect the kidneys from precipita- the inflow graft occludes. tion of myoglobin within the renal tubules are The early signs and symptoms of compart- instituted in all patients with compartment ment syndrome are the 3 P’s: pink, painful, syndrome. Alkalinization of the urine is and pulses (present). Before the capillary leak accomplished by administration of intravenous induced by the ischemia-reperfusion causes sodium bicarbonate, and close monitoring of intracompartment pressures to eventually ex- serum electrolytes as well as serum myoglobin ceed mean arterial pressure, there is a palpable and creatine kinase (CK) levels is continued pulse in the involved limb. The skin appears until the syndrome subsides. In patients with pink as the dermal plexus of arterioles main- documented myoglobinurea, we routinely tains perfusion despite ischemia of the underly- monitor urine pH to confirm alkalinization of ing muscle. The pain induced by compartment the urine. syndrome in the conscious patient is initially present only with motion of the muscles in the Outcomes affected compartment. Thus passive stretching of the first toe is one of the most sensitive tests The probability of limb salvage in acute lower for compartment syndrome of the anterior limb ischemia is dependent on two factors. The compartment of the lower leg. As the ischemia first and more important is the duration and becomes advanced, pain is present at rest degree of ischemia prior to revascularization. In and becomes excruciating. Immediate four- patients with prior peripheral vascular surgery, compartment fasciotomy is performed via diagnosis and treatment are usually not double incisions if there is any clinical suspi- delayed, as both the patient and physician are cion or signs of compartment syndrome after focused on ischemia as a cause of the symptoms revascularization. in the limb. As discussed above, patients with In the intubated or otherwise unresponsive arterial embolism or aortic dissection can be patient where the diagnosis is unclear, meas- misdiagnosed as having a primary nonvascular urement of intracompartment pressures with cause of their limb symptoms. The associated either a Stryker device or an intravenous infu- delay in treating the ischemia can often con- sion pump [with pressure sensing capability, tribute to ultimate limb loss. The second factor i.e., an intravenous accurate control (IVAC) in determining the outcome in acute limb machine] enables the diagnosis of compartment ischemia is the success of revascularization, syndrome to be made in the absence of the which is related to the level of disease responsi- characteristic signs and symptoms. Pressures ble for the acute ischemia. More proximal occlu- greater than 12 to 15mmHg are treated with sive disease, particularly aortoiliac disease or fasciotomy. Fasciotomy of the lower limb is occlusion, is readily treated with embolectomy usually performed through two incisions, or bypass and generally associated with good although a single incision fasciotomy with outcomes. Acute limb ischemia due to failure of fibulectomy can enable decompression of all a prior infrainguinal bypass graft placed for four fascial compartments. The skin incisions prior critical limb ischemia, particularly if there can often be closed at the time of fasciotomy, have been multiple prior bypass procedures and this allows more rapid healing than the in the involved limb, is associated with worse 104

VASCULAR SURGERY outcomes as the quality of the distal target with aortic aneurysms have evidence of an vessel and available bypass conduit progres- aneurysm in the lower limb when prospectively sively decreases. screened (Diwan et al.,2000) provides a basis for Long-term outcomes after arterial embolism such a strategy. are determined by the underlying medical con- dition of the patient, particularly the cardiac status. Despite long-term anticoagulation, up to References 20% of patients with arterial embolism suffer another embolic event. Ischemic neuropathy of Devine C, Hons B, McCollum C. (2001) J Vasc Surg 33: either the sensory or motor nerves can persist 533–9. after revascularization for acute limb ischemia, Diwan A, Sarkar R, Stanley JC, Zelenock GB, Wakefield TW. and can be a source of frustration to both the (2000) J Vasc Surg 31:863–9. patient and physician. Newer nonnarcotic Gardner AW, Poehlman ET. (1995) JAMA 274:975–80. Harris PL, How TV, Jones DR. (1987) Br J Surg 74:252–5. modalities for chronic pain and dysesthesia are Kreienberg PB, Darling RC 3rd, Chang BB, et al. (2002) J Vasc emerging, including electrical nerve stimula- Surg 35:299–306. tion, use of tricyclic drugs, and other options to Lederman RJ, Mendelsohn FO, Anderson RD, et al. (2002) treat chronic neuropathy. Lancet 359:2053–8. Patients who present with acute ischemia sec- Money SR, Herd JA, Isaacsohn JL, et al. (1998) J Vasc Surg 27:267–74; discussion 274–5. ondary to thrombosis of a popliteal aneurysm Slonim SM, Nyman U, Semba CP, Miller DC, Mitchell RS, have a high rate (40% to 50%) of limb loss Dake MD. (1996) J Vasc Surg 23:241–51; discussion despite modern advances in thrombolytic 251–3. therapy and peripheral bypass surgery. These Tateishi-Yuyama E, Matsubara H, Murohara T, et al. (2002) Lancet 360:427–35. results reinforce the need to aggressively diag- Veith FJ, Gupta SK,Ascer E, et al. (1986) J Vasc Surg 3:104–14. nose and treat popliteal aneurysms prior to Wengerter KR, Yang PM, Veith FJ, Gupta SK, Panetta TF. thrombosis, and the finding that 15% of patients (1992) J Vasc Surg 15:143–9; discussion 150–1. 10 Chronic Venous Insufficiency, Varicose Veins, Lymphedema, and Arteriovenous Fistulas Andrew W. Bradbury and Peter J. Pappas

Chronic Venous Insufficiency venous ulceration (CVU) are 30% to 50%, 5% to 10%, and 1% to 2%, respectively. The bulk of Chronic venous insufficiency (CVI) may be advanced disease affects the elderly, with up to defined as symptom or signs of ambulatory 5% of women over the age of 65 years having a venous hypertension. In developed countries, history of CVU. However, up to 50% of affected CVI affects up to half of the adult population. patients, especially men, develop their ulcer Furthermore, the treatment of CVI consumes before their 50th birthday. Women often relate up to 2% of total health spending and is a major the development of VVs to pregnancy and child- cause of lost economic productivity. These birth. The increase in female sex hormones and startling data, coupled with the ineffectiveness blood volume during the first trimester may be of current treatment modalities in many of the responsible. However, there is little evidence of most severely affected patients, underscore the an association with (multi)parity, and men and need for more research. women appear to be affected almost equally by CVI. The excess of women observed in clinical practice is mainly due to their longevity and the Classification reluctance of men to seek medical attention. There is no clear evidence that low socioeco- Chronic venous insufficiency has proved nomic class predisposes to CVI, although CVU difficult to classify for the purposes of scientific healing and recurrence rates may be worse. reporting. This has obfuscated attempts to Clinical experience suggests that occupations directly compare the findings of different epi- involving prolonged standing are associated demiological, pathophysiological, and clinical with an increased prevalence and severity of studies. The clinical, etiological, anatomical, and CVI, poor ulcer healing, and increased recur- pathophysiological (CEAP) classification, pro- rence rates. Data on the relationships between posed in 1994 by the American Venous Forum, physical activity and CVI are conflicting, but it is now the most widely accepted system seems reasonable to assume that an individual (Table 10.1). with a well-developed calf muscle pump is less likely to develop CVI. Although a consistent Epidemiology relationship between weight and height is lacking,VVs appear to be commoner in tall men In industrialized countries the lifetime risks of and CVU in obese women. Similarly, there is developing varicose veins (VVs), skin changes growing evidence of a hereditary predisposition (corona phlebectatica, lipodermatosclerosis, to CVI. For example, patients whose parents varicose eczema, atrophie blanche), and chronic both have VVs have a 90% chance of developing

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Table 10.1. Clinical, etiological, anatomic, and saphenous vein (LSV) and short saphenous pathophysiological (CEAP) classification vein (SSV) and their tributaries. As there are Clinical1 numerous communications between the long Class 0 No visible or palpable signs of venous and short saphenous systems, and between the disease superficial and deep systems through junctional Class 1 Telangiectasia2 or reticular veins3 and nonjunctional perforators, these three ele- 4 Class 2 Varicose veins ments are highly interdependent, both anatom- Class 3 Edema ically and functionally, in health and in disease. Class 4 Skin changes (lipodermatosclerosis, Most of the blood draining into the superficial atrophie blanche, eczema) Class 5 Healed ulceration veins from skin and subcutaneous tissues Class 6 Active ulceration immediately enters the deep venous system via perforators in the foot, calf, and thigh. In healthy Etiological subjects, less that 10% of the total venous return EC Congenital (may be present at birth or from the lower limb passes through the LSV and recognized later) E Primary (with undetermined cause) SSV to the saphenofemoral junction (SFJ) and P saphenopopliteal junction (SPJ), respectively. ES Secondary (with known cause): postthrombotic, posttraumatic, Blood is forced back up the leg during leg other muscle systole, and prevented from flowing back down the leg under the influence of gravity Anatomical 5 during diastole, through the actions of the AS Superficial veins (numbered 1 to 5) 6 muscle pumps and closure of venous valves, AD Deep veins (numbered 6 to 16) AP Perforating veins (numbered 17 and respectively. The act of walking sequentially 18) compresses venous sinuses in the sole of the foot, the calf (soleus, gastrocnemius), and to a Pathophysiological P Reflux lesser extent the thigh and buttock. During R relaxation these sinuses fill from the deep and PO Obstruction PR,O Both superficial venous systems and valves close in the superficial and axial veins to prevent reverse 1 Supplemented with (A) for asymptomatic or (S) for symptomatic, flow (reflux). In both the superficial and deep e.g., C6,A. systems, the density of valves is greatest in the 2 Intradermal venules up to 1mm in diameter. 3 Subdermal, nonpalpable venules up to 4mm. calf and gradually diminishes in the thigh. The 4 Palpable subdermal veins usually larger than 4mm. iliac veins and inferior vena cava are frequently 5 Telangiectasia/reticular veins (1); greater (long) saphenous vein devoid of valves. above (2) below (3) knee; lesser (short) saphenous vein (4); non- When standing completely motionless, with saphenous (5). all the leg muscles relaxed, the venous valve 6 Inferior vena cava (6); common (7), internal (8), external (9) iliac; pelvic (10); common (11), deep (12), superficial (13) femoral; leaflets come to lie in a neutral midposition. As popliteal (14); crural (15); muscular (16). a result, the venous pressure in the dorsal foot veins comes to represent the hydrostatic pres- sure exerted by the unbroken column of venous blood stretching up from the foot to the right atrium (approximately 90 to 100mmHg in a VVs,and CVU patients have a higher prevalence person of average height). Contraction of the leg of inherited thrombophilia (TP). The influence muscles immediately leads to the compression of race and ethnicity is unclear, as there are few of deep veins and sinuses and to the movement reliable data from nonwhite populations. of venous blood cranially. Retrograde blood flow is terminated by valve closure, and perfo- Normal Venous Function rators that allow unidirectional flow from the superficial to the deep venous system only. Venous blood from the lower limbs returns to Conventionally, this has also been ascribed to the right heart against gravity through the deep the closure of valves within the perforators. and superficial venous systems. The deep veins However, several studies have shown that many follow the named arteries and are often paired. perforators are devoid of valves. Instead, The superficial system comprises the long outward flow through perforators may be 107

CHRONIC VENOUS INSUFFICIENCY,VARICOSE VEINS, LYMPHEDEMA,AND ARTERIOVENOUS FISTULAS limited by external compression from contract- and reflux. As the vein dilates, the tension ing muscle and a pinch-cock mechanism involv- in the wall increases according to the law of ing the deep fascia. The importance of these Laplace, which leads to further dilatation. mechanisms is that the very high pressures The end result is an incompetent,elongated (up to 200mmHg) generated within the calf and tortuous varicose vein. Primary valvu- muscle pump are used exclusively to propel lar incompetence may also affect the deep blood back up the leg against gravity, and are venous system. not transmitted to the superficial or distal deep Postthrombotic syndrome (PTS): Approxi- systems. When the muscle pump relaxes, the mately 25% of CVU patients have a clear previously expelled venous blood tends to flow history of deep venous thrombosis (DVT), caudally under gravity but is prevented from and many more have probably suffered a doing so by valve closure. This has the effect of subclinical or undiagnosed thrombosis. dividing a single long (and heavy) column of Deep venous thrombosis leads to endothe- blood into a series of shorter columns lying lial hypoxia, valvular destruction, and between closed valves. The pressure within each mural inflammation. Even though most of these segments is low and the ambulatory DVTs recanalize, the end result is a thick- venous pressure (AVP) in the dorsal foot veins ened, valveless tube that permits gross falls typically to <25mmHg. During muscle reflux and poses an anatomical (narrow- pump diastole, blood in the superficial system ing, fibrous webs) and functional (lack flows in to the deep system along a pressure of compliance) obstruction to venous gradient. outflow. Obstruction leads to the formation of collateral pathways. For example, blood may be forced out of the calf via perfora- Pathophysiology tors into the superficial venous system and There are three basic mechanisms that lead to thence up the leg with the formation of raised AVP and the symptoms and signs of CVI: secondary VVs. Removal of such VVs (1) muscle pump dysfunction, (2) valvular increases AVP. Most patients with severe reflux, and (3) venous obstruction. and intractable CVU have PTS. Aging, general debility, and a wide range of musculoskeletal or neurological lower limb Clinical Assessment pathologies can impair calf muscle pump func- tion. The “fixed” ankle secondary to arthritis or History trauma is a common example. Muscle bulk and Inquiry should be made as to the duration of the tone are also important factors in the mainte- present ulcer as well as the duration of ulcer nance of perforator competence (see above). disease, the number of episodes, and any pre- Failure of perforator competence leads to calf cipitating factors (Table 10.2). Previous treat- pump inefficiency (akin to mitral regurgita- ment history and contact allergies are recorded. tion), as well as the transmission of high pres- Peripheral artery disease (20%), diabetes melli- sures directly to the skin of the gaiter area. tus (5%), and rheumatoid arthritis (8%) often Reflux is present in more than 90% of patients coexist. Malignancy must not be overlooked. with CVI; 5% to 10% have isolated deep, 30% to Many patients with lower limb symptoms, and 50% isolated superficial, and 50% to 60% com- who coincidentally have VVs, have other pathol- bined. In general, superficial reflux has a better ogy to explain their symptoms. Orthopedic, prognosis than deep reflux (especially when the neurological, and arterial causes of leg symp- latter is postphlebitic), and proximal reflux has toms must be excluded. Particular attention a better prognosis than distal reflux. Valvular must be paid to a history of “white leg” of preg- reflux can arise in two ways that are not mutu- nancy, prolonged immobilization, phlebitis, and ally exclusive in any one patient: major lower limb fracture, any of which may Primary valvular incompetence (PVI): A loss suggest previous the PTS. A family history of of elastin and collagen in the vein wall venous disease, particularly early-onset, recur- around the valve commissures leads to rent, or unusual thrombotic events, should be dilatation, separation of the valve leaflets, sought (Cornu-Thenard, 1994). 108

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Table 10.2. Distinguishing features of arterial and venous ulcers Clinical features Arterial ulcer Venous ulcer Gender Men > women Women > men Age Usually presents >60 years Typically develops at 40–60 years but patient may not present for medical attention until much older; multiple recurrences are the norm Risk factors Smoking, diabetes, hyperlipidemia and Previous DVT, thrombophilia, varicose veins hypertension Past medical history Most have a clear history peripheral, More than 20% have clear history of DVT, many coronary, and cerebrovascular disease more have a history suggestive of occult DVT, e.g., leg swelling after childbirth, hip/knee replacement or long bone fracture Symptoms Severe pain is present unless there is About a third have pain but it is not usually (diabetic) neuropathy, pain may be severe and may be relieved on elevation relieved by dependency Site Normal and abnormal (diabetics) Medial (70%), lateral (20%) or both malleoli and pressure areas (malleoli, heel, gaiter area metatarsal heads, fifth metatarsal base) Edge Regular, punched-out, indolent Irregular, with neoepithelium (whiter than mature skin) Base Deep, green (sloughy) or black (necrotic) Pink and granulating but may be covered in with no granulation tissue, may yellow-green slough comprise major tendon, bone and joint Surrounding skin Features of SLI LDS, varicose eczema, atrophie blanche Veins Empty, guttering on elevation Full, usually varicose Swelling Usually absent Often present

Symptoms Corona phlebectatica (ankle/malleolar flare): One of the earliest skin manifestations of Localized discomfort in the leg: Usually at the CVI comprises dilated intra/subdermal site of the visible VV,particularly after pro- veins at or just below the medial malleolus. longed standing. Prominent varices may Overlying skin is thin and fragile leading be tender, particularly in menstruating to a blue-bleb appearance. Trauma women. frequently leads to hemorrhage and Pain: Severe pain is unusual and suggests ulceration. infection or arterial insufficiency. Lipodermatosclerosis: The skin is brown Swelling: A feeling of swelling is common. (red or purple) and indurated due to Venous claudication: This is unusual and due hemosiderin and plasma protein deposi- to extensive postthrombotic iliofemoral tion, leading to dermal fibrosis. venous occlusion. There is bursting pain in Atrophie blanche: Thin and pale skin due to the calf on walking, which is relieved only the thrombotic obliteration of papillary by elevating the leg. In addition, patients capillaries; often at the site of previous often complain of heaviness in the calf with ulceration. ambulation. Varicose eczema: Scaly dry (or weeping) Itching: This is common and may lead to skin that is often intensely pruritic and scratching, infection, and ulceration. can demonstrate blanching erythema (mimicking cellulitis). Physical Examination Edema: A common presentation in patients with CEAP class 3 or greater CVI. Chronic Varicose veins: Note the distribution of venous insufficiency may coexist with varices and any surgical scars. other diseases that cause edema, such as 109

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congestive heart failure, and must be reflux, the location of the SPJ and nonjunctional considered when evaluating CVI patients perforators, and whether the deep veins are (Table 10.3). patent. Plethysmography involves the assess- Hemorrhage: Can be alarming, even life ment of venous function through the measure- threatening, may be spontaneous or follow ment of limb volume and nowadays is primarily trauma. Direct pressure and elevation a research tool. Photo (PPG) and air (APG) always arrest venous hemorrhage. As plethysmography are probably the most recurrent bleeding is almost inevitable, popular techniques. Ambulatory venous pres- the patient should be hospitalized for sure is measured by cannulating and transduc- definitive treatment. ing a dorsal foot vein; it remains the research Ulceration: Most CVUs can be easily differen- reference standard. Ascending tiated from other forms of ulceration. determines the presence of residual thrombus, the extent of recanalization,and the distribution Arterial circulation: If pedal pulses are impal- of collaterals. Contrast medium is injected into pable, measure the ankle–brachial index < a dorsal foot vein and directed into the deep (ABI). An ABI of 0.8 mandates referral to veins by the placement of an ankle tourniquet. a vascular surgeon. The ABI is unreliable in The iliac system and the vena cava may not be diabetic patients. visualized, in which case a separate injection can be made in the common femoral vein (CFV) Investigations (cavography). Descending venography involves injecting contrast medium into the CFV with Virtually all patients with CVI require further the subject positioned at 60 degrees with the investigation, and duplex ultrasound (DU) has head up in order to assess reflux. Venography is largely replaced all other modalities in routine largely reserved for patients being considered clinical practice. It allows Doppler velocity for deep venous reconstruction because it is information to be color coded and superim- superior to DU in determining the presence and posed in real time upon a gray scale (B-mode) extent of the PTS. Ovarian vein reflux and pelvic image. It determines the location and severity of varices can be visualized by placing a catheter into the ovarian or internal iliac veins via the CFV approach. As well as this imaging being diagnostic, it also enables the ovarian vein to be Table 10.3. Etiological classification of lymphedema embolized in women suffering from pelvic Primary Congenita (onset <2 years old): congestion syndrome. Ulcers that fail to heal, lymphedema sporadic tend to bleed, or have unusual features should Congenita (onset <2 years old): be biopsied at base and margin under local familial (Milroy’s disease) anesthesia. Praecox (onset 2–35 years): sporadic Praecox (onset 2–35 years): familial (Meige’s disease) Nonsurgical Management Tarda (onset after 35 years of age) The mainstay of treatment is compression with Secondary Bacterial infection or without superficial venous surgery in the lymphedema Parasitic infection (filariasis) great majority of patients who have CVI due to Fungal infection (tinea pedis) reflux. A small minority of patients who have Exposure to foreign-body deep venous obstruction may benefit from material (silica particles) surgical or endovascular reconstruction. There Primary lymphatic malignancy Metastatic spread to lymph nodes is considerable controversy over the role of Radiotherapy to lymph nodes . Surgical excision of lymph nodes Trauma (particularly degloving injuries) Dressings Superficial Deep venous thrombosis No particular dressing or topical agent has been shown unequivocally to significantly 110

VASCULAR SURGERY hasten CVU healing. However, they do have and act as a scaffold for the patient’s own epithe- different physical properties, and the surgeon lial cells. But they are extremely expensive and needs to have a basic grasp of the underlying as yet unproven. science (and art) of wound care. Enzymatic agents (e.g., streptokinase-streptodornase) Topical Agents undoubtedly digest the constituents of slough. However, they are relatively ineffective against Dermatitis is common and may be endogenous deep necrosis or hard eschar. There is evidence (varicose or venous stasis dermatitis) or that they speed up healing, and may damage the exogenous due to topically applied substances wound environment. Hydrocolloid dressings (contact dermatitis). Dermatitis is extremely come in many forms, and are generally imper- morbid,associated with nonhealing,and may be meable to gases, water vapor, and bacteria. They irritant or allergic due to cell-mediated, delayed produce a moist, acidic, low-oxygen tension hypersensitivity. Early patch testing is manda- wound environment that has been shown exper- tory. The use of bland paraffin preparations imentally to enhance wound healing. Patients greatly reduces the risks of dermatitis. In like these dressings because they are easy to use, patients with marked exudate, zinc oxide paste and patients can bathe with the dressing in situ. can be used to protect the surrounding skin. The dressings absorb exudate (reducing the fre- Acute dermatitis must be treated with removal quency of dressing changes, smell, risks of of the offending allergen and topical steroid cross-infection, and costs) and may provide therapy. Topical antibiotics should be avoided. superior pain relief. However, in randomized controlled trials where both treatment arms Physical Therapy have received equal and adequate compression, hydrocolloid dressings have not be shown to Prolonged bed rest with leg elevation will heal improve overall healing compared to any other virtually all CVUs. However, it is logistically dressing. Bead dressings (such as cadexomer impossible, and associated with decubitus com- iodine and dextranomer) comprise hydrophilic, plications, and as it does not address the under- polysaccharide materials that absorb large lying hemodynamic abnormality, recurrence is amounts of fluid and slough. The former also virtually inevitable. Exercise therapy aimed at releases iodine in to the wound. Although they improving calf muscle pump function may be of may speed up desloughing, they have not been benefit and trials are under way. shown to enhance healing. Paste bandages com- prise a plain weave cotton fabric impregnated Compression Therapy with zinc oxide paste, either alone or with calamine, calamine and clioquinol, coal tar, or Compression undoubtedly retards the develop- ichthammol. These additives are designed to ment and progression of CVI. However, it is still soothe venous eczema but are actually a more of an art than a science, and the quality of common cause of contract allergy, and patch scientific reporting remains low. Elastic band- testing is recommended. Paste bandages do not aging (the four-layer bandage) is favored in the retain moisture, and for this reason, and to United Kingdom, whereas in mainland Europe apply compression, additional layers of bandag- and North America inelastic bandaging (the ing are required. The Unna boot is a paste Unna boot) is preferred. The four-layer bandage bandage containing glycerin that hardens into comprises orthopedic wool (to protect the bony semirigid dressing. In trials where equal prominences and to absorb any exudates); crepe amounts of compression are applied, no form of bandage (to compress and shape the wool, and paste bandage has been shown to improve to provide a firm base for the compression healing over other forms of dressing. Their bandages), elastic bandage (e.g., ElsetTM, Seton, principal benefit is provision of inelastic com- applied at 50% stretch) and a self-adhesive elas- pression.Alginate dressings absorb exudate and ticated bandage (e.g., CobanTM, 3M to add to create a moist wound environment but have not compression and fix the bandaging in place). been proved to speed healing. Biological dress- This bandage typically exerts 40mmHg at the ings comprising cultured human epithelium or ankle and 20mmHg just below the knee. Once fibroblasts may act as a source of growth factors the ulcer is healed, the patient should be pre- 111

CHRONIC VENOUS INSUFFICIENCY,VARICOSE VEINS, LYMPHEDEMA,AND ARTERIOVENOUS FISTULAS scribed stocking. There is no evidence that is different from that for uncomplicated VVs in extending compression above the knee confers a number of important ways. The patients are benefit. Compliance is a major problem. older and often have multisystem, medical comorbidity; the risks, especially DVT, are Sclerotherapy higher. Patients may require inpatient optimiza- tion of cardiorespiratory function, treatment of The role of sclerotherapy is controversial, with dermatitis, edema reduction, and desloughing practitioner’s views based largely on profes- of the ulcer. The effect of deep venous reflux on sional background and country of origin rather the efficacy of superficial venous surgery is con- than on clinical comparative studies. Some scle- troversial and incompletely defined. Deep reflux rotherapists believe they can treat all VVs, but due to PVI may reverse once superficial reflux most accept the superiority of surgery in the has been eradicated. However, most agree that presence of main stem, SFJ, or SPJ incompe- patients with extensive PTS gain less benefit tence. However, the advent of foam sclerosants from surgery. Secondary VVs that are acting as may revolutionize the management of such collaterals must not be removed.Although post- disease. The aim is to place a small volume of operative compression therapy has been shown sclerosant in the lumen of a vein empty of to reduce VVs and CVU recurrence, compliance blood, and then appose the walls of that vein is poor. with appropriate compression. The vein then fibroses closed without the formation of clot. Some practitioners use magnifying loupes for Varicose Vein Surgery smaller veins, and there is increasing interest in Long Saphenous Surgery injecting larger veins under ultrasound guid- ance (echosclerotherapy).The vein must be kept Safe and effective surgery depends on observing empty of blood both during and after the injec- a few sound principles. In a patient of normal tion to prevent thrombophlebitis. Adequate build the SFJ lies directly beneath the groin compression is difficult in the perineum, upper crease; in the obese it lies above. An incision thigh, and popliteal fossa, especially in the made below the crease is likely to be too low. obese. Patients should be mobilized immedi- Resist the temptation to operate through an ately afterward. In the U.K., most surgeons use excessively small incision. Do not divide any detergents that act by directly damaging the vein until the SFJ has been unequivocally iden- endothelium. In mainland Europe and North tified. Unless all tributaries are taken beyond America, hypertonic saline is also popular. Err secondary branch points, a network remains of on the side of caution with regard to volume and superficial veins connecting the veins of the concentration until the patient’s response can thigh with those of the perineum, the lower be assessed. The complications of injection abdominal wall, and the iliac region. These sclerotherapy include anaphylaxis (<0.1%), cross-groin connections are a frequent cause of allergic reactions (uncommon), ulceration recurrence. Ligate the LSV deep to all tributar- (extravascular injection), arterial injection (rare ies flush with the CFV using nonabsorbable and serious), pigmentation (extravasation), transfixion suture to reduce neovascularization superficial thrombophlebitis (inadequate com- through the stump. Directly ligate, and if large, pression), and DVT (inadequate mobilization). consider stripping, any high anterolateral or posteromedial or thigh branches to reduce Surgical Management hematoma formation and recurrence. There is evidence to show that stripping the LSV to a There is growing evidence that saphenous hand’s breadth below the knee significantly surgery improves the quality of life in patients reduces recurrence by disconnecting the thigh with VVs, and augments the healing and perforators and saphenous tributaries and by reduces the recurrence of CVU better than com- removing the conduit that will allow neovascu- pression alone (Dwerryhouse et al., 1999). For larization in the groin to reconnect with the optimal results, it is necessary to define the remaining superficial venous system of the extent and severity of venous disease, usually by thigh and calf. Confining stripping to just below means of DU, prior to surgery. Surgery for CVU the knee, and to a downward direction, reduces 112

VASCULAR SURGERY saphenous nerve injury. The theoretical advan- randomized controlled trial of compression vs. tages of invagination stripping in terms of compression and saphenous surgery vs. com- reducing blood loss, hematoma, nerve injury, pression, saphenous surgery, and SEPS. and scars have not been confirmed in trials. Surgery for Recurrent Veins Short Saphenous Surgery Recurrent LSV VVs arise because of inadequate Saphenopopliteal junction ligation can prove to dissection of, or neovascularization at, the SFJ in be a challenging procedure, especially when the presence of a nonstripped or incompletely performed for recurrent disease. Always mark stripped LSV. Standard teaching is to approach the junction preoperatively with DU (some the SFJ through nonoperated tissues (usually surgeon still prefer venography). The SSV can from a lateral approach that first exposes the be found by following the Giacomini vein,which common femoral artery) so that the CFV can be is a superficially placed tributary of the SSV that skeletonized of branches using nonabsorbable runs up the thigh to join the LSV. This may be sutures for 1 to 2cm above and below the junc- large and confused with the SSV,especially if the tion. The top of the LSV is dissected from the SPJ is absent; the importance of this will be mass of scar tissue so that it can be stripped. apparent on the preoperative DU. Be aware that However, this can be a difficult and potentially traction on the SSV can tent up and damage the morbid operation. When the preoperative DU mobile and thin-walled popliteal vein. Palpation indicates neovascularization as opposed to an of the artery gives an indication of the depth of intact SFJ, the LSV can be located at the knee, a dissection. Beware the common peroneal nerve stripper passed up toward the groin, and the under medial edge of biceps femoris, which is vein stripped without a formal redissection. at risk from overzealous lateral retraction as well as from a careless stitch when closing the Complications popliteal fascia. The SSV is often closely associ- Fortunately, major complications following VV ated with sural nerve injury and is also at risk, surgery are relatively rare. However, up to 20% particular if stripping is undertaken. There are of patients may suffer some form of minor mor- still a number of controversial issues regarding bidity, such as hematoma, lymphatic leak, pain, the SSV. Is it always necessary to ligate the SSV saphenous neuritis, and venous thrombosis. In flush with the popliteal vein? Experience sug- the U.K., VV surgery is the commonest cause of gests that this counsel of perfection is hard to litigation against general and vascular surgeons. achieve in a significant proportion of patients This not a field for the unsupervised, inexperi- without risk of collateral damage.This raises the enced surgeon and it behooves surgeons who question of what should be done with the gas- undertake VV surgery to carefully audit their trocnemius and other, often large and refluxing, management, techniques, and outcomes. muscular veins? Should the SSV be stripped or is it permissible just to remove a segment Deep Venous Reconstruction through the popliteal fossa wound? It seems likely, although there is no proof, that SSV strip- These procedures have not gained widespread ping, for the same reasons as for the LSV,would acceptance largely because there is little data to reduce recurrence. However, there is concern support their efficacy. Several different tech- about sural nerve injury. niques have been described for suturing the edges of “floppy” valve cusps to the vein wall, Perforator Ligation rendering the valve competent. Autologous valve transplantation interposes a segment of Although the advent of DU-guided subfascial axillary or brachial vein,containing a competent endoscopic perforator surgery (SEPS) has valve, into an incompetent deep vein, usually the rekindled interest in perforator ligation, there is popliteal. Procedures using synthetic, mixed, no evidence that it alters the natural history of and animal valves are still experimental. An venous disease. Clearly, the only way to resolve incompetent superficial femoral vein can be this issue once and for all is to perform a transected and anastomosed end to end or end 113

CHRONIC VENOUS INSUFFICIENCY,VARICOSE VEINS, LYMPHEDEMA,AND ARTERIOVENOUS FISTULAS to side to a profunda femoris or long saphenous the interstitial fluid (ISF) and returns them vein that has a competent valve (vein transposi- to the circulation. tion). An obstructed femoral segment may be 2. It permits the circulation of lymphocytes bypassed by anastomosing a transected, compe- and other immune cells. tent LSV to the side of the popliteal vein. Again, 3. It returns intestinal lymph (chyle), which satisfactory long-term patency rates have been transports cholesterol, long chain fatty reported in small series. acids, triglycerides, and the fat-soluble vitamins (A, D, E, and K), directly to the Conclusions circulation, bypassing the liver. Although the most difficult cases of leg ulcera- Lymph from the lower limbs and abdomen tion are multifactorial in origin, CVI is the drains via the cisterna chyli and thoracic duct single most common underlying pathology. As into the left internal jugular vein at its such, there is hope that the prevalence of CVU confluence with the left subclavian vein. Lymph may decline in the future as a result of improved from the head and right arm drains via the right thromboembolic prophylaxis and treatment. lymphatic duct into the right internal jugular For the moment, however, CVU is a common vein. Lymphatics accompany veins everywhere and disabling condition that is often resistant to except in the cortical bony skeleton and central conservative therapy, prone to recurrence, and nervous system, although the brain and retina very expensive to manage. There needs to be a possess cerebrospinal fluid and aqueous humor, low threshold for referral to a vascular surgeon, respectively. The lymphatic system comprises preferably through a one-stop assessment clinic lymphatic channels, lymphoid organs (lymph where a thorough venous and arterial duplex- nodes, spleen, Peyer’s patches, thymus, tonsils), based assessment can be performed. This will and circulating elements (lymphocytes and enable patients who might benefit from surgical other mononuclear immune cells). intervention to be identified and treated early. It Lymphatics originate within the ISF space will also enable ongoing outpatient treatment to from specialized endothelialized capillaries be based on an in-depth understanding of the (initial lymphatics) or nonendothelialized pathophysiological mechanisms responsible in channels such as the spaces of Disse in the liver. each patient. Great progress in the management Initial lymphatics are unlike arteriovenous cap- of CVU has been made over the last decade illaries in that they are blind-ended, are much because of an increased understanding of the larger (50mm) and allow the entry of molecules pathophysiology and the availability of data up to 1000kd in size. This is because the from clinical trials that have provided a basement membrane of these lymphatics is scientifically robust platform on which to base fenestrated, tenuous, or lacking intra- and treatment algorithms. Despite all this, further intercellular endothelial pores. Lymphatic capil- research is required into the epidemiology and laries are anchored to interstitial matrix by natural history of CVU, models of care, primary filaments. In the resting state they are collapsed, prevention, and pathogenesis. but when ISF volume and pressure increases, they are held open by these filaments to facili- tate increased drainage. Initial lymphatics drain Lymphedema into terminal (collecting) lymphatics that possess bicuspid valves and endothelial cells The Lymphatic System rich in the contractile protein actin. Larger col- lecting lymphatics are surrounded by smooth The lymphatic system performs the following muscle.Valves partition the lymphatics into seg- functions: ments (lymphangions) that contract sequen- 1. It removes water, electrolytes, low- tially in order to propel lymph into the lymph molecular-weight moieties (polypeptides, trunks. Terminal lymphatics lead to lymph cytokines, growth factors), and macromol- trunks comprising endothelium, basement ecules (fibrinogen, albumen, globulins, membrane, and a media of smooth muscle coagulation and fibrinolytic factors) from cells that are innervated with sympathetic, 114

VASCULAR SURGERY parasympathetic, and sensory nerve endings. venous circulation. In one sense, all edema is About 10% of lymph arising from a limb is lymphedema in that it results from an inability transported in deep lymphatic trunks that of the lymphatic system to clear the ISF com- accompany the main neurovascular bundles. partment. However, in most types of edema this The majority of lymphatic flow, however, is con- is because the capillary filtration rate is patho- ducted against the venous flow from deep to logically high and overwhelms a normal lym- superficial in epifascial lymph trunks. Super- phatic system, resulting in the accumulation of ficial trunks form lymph bundles of various low-protein edema fluid. By contrast, in true sizes, are located within strips of adipose tissue, lymphedema, capillary filtration is normal and and tend to follow the course of the major the edema fluid is relatively high in protein. superficial veins. Both mechanisms frequently coexist, as in The distribution of fluid and protein between patients with CVI. the vascular and ISF spaces depends on hydro- Lymphedema can result from lymphatic static and oncotic pressures (Starling’s forces), aplasia, hypoplasia, dysmotility (reduced con- together with the relative impermeability of the tractility with or without valvular insuffi- blood capillary membrane to molecules over ciency), obliteration by inflammatory, infective 70kd. In healthy subjects there is net capillary or neoplastic processes, or surgical extirpation filtration, which is removed by the lymphatic (Table 10.4).Whatever the primary abnormality, system. Small particles enter the initial lym- the resultant physical or functional obstruction phatics directly; larger particles are phagocy- leads to lymphatic hypertension and distention tosed by macrophages and transported through with further secondary impairment of contrac- the lymphatic system intracellularly. Lymph tility and valvular competence. Lymphostasis flows against a small pressure gradient due to and lymphotension lead to the accumulation in transient increases in interstitial pressure sec- the ISF of fluid, proteins, growth factors and ondary to muscular contraction and external other active peptide moieties, glycosaminogly- compression, the sequential contraction and cans, and particulate matter, including bacteria. relaxation of lymphangions, and the prevention As a consequence, there is increased collagen of reflux due to valves. Lymphangions respond production by fibroblasts, an accumulation to increased lymph flow in much the same way of inflammatory cells (predominantly macro- as the heart responds to increased venous phages and lymphocytes), and activation of ker- return in that they increase their contractility atinocytes. The end result is protein-rich edema and stroke volume.Transport in the main lymph fluid, increased deposition of ground substance, ducts also depends on intrathoracic (respira- subdermal fibrosis, and dermal thickening and tion) and central venous (cardiac cycle) pres- proliferation. Lymphedema, unlike all other sures. In the healthy limb, lymph flow is largely types of edema, is confined to the epifascial due to intrinsic lymphatic contractility aug- space. Although muscle compartments may mented by exercise, limb movement, and exter- be hypertrophied due to the increased work nal compression. However, in lymphedema, involved in limb movement, they are character- where the lymphatics are constantly distended istically free of edema. with lymph, these external forces assume a Two main types of lymphedema are much more important functional role. recognized: • Primary, in which the cause is unknown Definition and Pathophysiology (or at least uncertain and unproved) but often presumed to be due to congenital Lymphedema may be defined as abnormal limb lymphatic dysplasia swelling due to the accumulation of increased amounts of high-protein ISF secondary to • Secondary, in which there is a clear under- defective lymphatic drainage in the presence of lying cause such as inflammation, malig- (near) normal net capillary filtration (Szuba and nancy, or surgery Rockson, 1997). In order for edema to be clini- Primary lymphedema is usually further subdi- cally detectable, the ISF volume has to double. vided on the basis of the presence of a family About 8L of lymph is produced and, following history, age of onset, and lymphangiographic resorption in lymph nodes, about 4L enters the findings (see below). 115

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Table 10.4. Differential diagnosis of the swollen limb Nonvascular or lymphatic General disease states Cardiac failure from any cause; liver failure; hypoproteinemia due to nephrotic syndrome, malabsorption, protein losing enteropathy; hyperthyroidism (myxedema); allergic disorders including angioedema and idiopathic cyclic edema; prolonged immobility and lower lib dependency Local disease processes Ruptured Baker’s cyst; myositis ossificans; bony or soft tissue tumors; arthritis; hemarthrosis; calf muscle hematoma; Achilles tendon rupture Retroperitoneal fibrosis May lead to arterial, venous and lymphatic abnormalities Gigantism Rare; all tissues are uniformly enlarged Drugs Corticosteroids; estrogens; progestogens; monoamine oxidase inhibitors; phenylbutazone; methyldopa; hydralazine; nifedipine Trauma Painful swelling due to reflex sympathetic dystrophy Obesity Lipodystrophy, lipoidosis Venous Deep venous thrombosis There may be an obvious predisposing factor such as recent surgery; the classical signs of pain and redness may be absent Postthrombotic syndrome Swelling, usually of the whole leg, due to iliofemoral venous obstruction; venous skin changes, secondary varicose veins on the leg and collateral veins on the lower abdominal wall; venous claudication may be present Varicose veins Simple primary varicose veins are rarely the cause of significant leg swelling Klippel-Trenaunay Rare; present at birth or develops in early childhood; comprises syndrome and other an abnormal lateral venous complex, capillary nevus, bony malformations abnormalities, hypo(a)plasia of deep veins, and limb lengthening; lymphatic abnormalities often coexist External venous Pelvic or abdominal tumor including the gravid uterus; compression retroperitoneal fibrosis Ischemia- reperfusion Following lower limb revascularization for chronic and particularly chronic ischemia Arterial Arteriovenous May be associated with local or generalized swelling malformation Aneurysm Popliteal; femoral; false aneurysm following (iatrogenic) trauma

Epidemiology metic problem. However, early diagnosis and treatment are important because relatively Lymphedema is estimated to affect around 2% simple measures can prevent the development of the population and causes significant physi- of disabling late disease, which is often very cal symptoms and complications, as well as difficult to treat. emotional and psychological distress, which can lead to difficulties with relationships, school, Clinical Assessment and work. Many sufferers choose not to seek medical advice because of embarrassment and In most cases the diagnosis of primary or sec- a belief that nothing can be done. Patients ondary lymphedema can be made, and the con- who do come forward, especially those with dition differentiated from other causes of a non–cancer-related lymphedema, often find swollen limb, on the basis of history and exam- they have limited access to appropriate expert- ination without recourse to complex investiga- ise and treatment. Lymphedema is often mis- tion. Unlike other types of edema, lymphedema diagnosed and mistreated by doctors, who characteristically involves the foot. The contour frequently have a poor understanding of the of the ankle is lost through infilling of the sub- condition, believing it to be primarily a cos- malleolar depressions; a “buffalo hump” forms 116

VASCULAR SURGERY on the dorsum of the foot, the toes appear of immune surveillance and so predisposes square due to confinement of footwear, and to other malignancies, although the causal the skin on the dorsum of the toes cannot association is not as definite as it is for be pinched due to subcutaneous fibrosis lymphangiosarcoma. (Stemmer’s sign). Lymphedema usually spreads proximally to knee level and less commonly Primary Lymphedema affects the whole leg. In the early stages, lym- phedema “pits,”and the patient reports that the It has been proposed that all cases of primary swelling is down in the morning. This repre- lymphedema are due to an inherited abnormal- sents a reversible component to the swelling, ity of the lymphatic system, sometimes termed which can be controlled. Failure to do so allows congenital lymphatic dysplasia. However, it is fibrosis, dermal thickening, and hyperkeratosis possible that many sporadic cases of primary to occur. In general, primary lymphedema lymphedema occur in the presence of a (near) progresses more slowly than secondary lym- normal lymphatic system and are actually phedema. Chronic eczema, fungal infection of examples of secondary lymphedema for which the skin (dermatophytosis) and nails (ony- the triggering events have gone unrecognized. chomycosis), fissuring, verrucae, and papillae These might include seemingly trivial (but (warts) are frequently seen in advanced disease. repeated) bacterial or fungal infections, insect Ulceration is unusual except in the presence of bites, barefoot walking (silica), DVT,or episodes chronic venous insufficiency. of superficial thrombophlebitis. In animal Lymphangiomas are dilated dermal lymphat- models, simple excision of lymph nodes or ics that blister onto the skin surface. The fluid is trunks leads to acute lymphedema that resolves usually clear but may be blood stained, and in within a few weeks, presumably due to collater- the long term they thrombose and fibrose, alization. In animals, the human condition can forming hard nodules, raising concerns about only be mimicked by inducing extensive lym- malignancy. If they are <5cm across, they phatic obliteration and fibrosis. Even then, there are termed lymphangioma circumscriptum; if may be considerable delay between the injury more widespread, lymphangioma diffusum. If and the onset of edema. Primary lymphedema they form a reticulate pattern of ridges, they are is much commoner in the legs than the arms. termed lymphedema ab igne. Lymphangiomas This may be due to gravity and a bipedal frequently weep (lymphorrhea, chylorrhea), posture, the fact that the lymphatic system of causing skin maceration and act as a portal the leg is less well developed, or the increased for infection. Protein-losing diarrhea, chylous susceptibility of the leg to trauma or infection. ascites, chylothorax, chyluria, and discharge Furthermore, loss of the venoarteriolar reflex from lymphangiomas suggest lymphangiectasia (VAR), which protects lower limb capillaries (megalymphatics) and chylous reflux. from excessive hydrostatic forces in the erect Ulceration, nonhealing bruises, and raised posture, with age and disease (CVI, diabetes) purple-red nodules should lead to suspicion of may be important. malignancy. Lymphangiosarcoma was origi- Primary lymphedema is often classified on nally described in postmastectomy edema the basis of apparent genetic susceptibility, age (Stewart-Treves syndrome) and affects about of onset, or lymphangiographic findings (Table 0.5% of patients at a mean onset of 10 years. 10.5). None of these is ideal, and the various However, lymphangiosarcoma can develop in classification systems in existence can appear any long-standing lymphedema but usually confusing and conflicting as various terms and takes longer to manifest (20 years). It presents eponyms are used loosely and interchangeably. as single or multiple bluish/red skin and subcu- This problem has hampered research and taneous nodules that spread to form satellite efforts to gain a better understanding of under- lesions that may then become confluent. The lying mechanisms, the effectiveness of therapy, diagnosis is usually made late, and confirmed and prognosis. Primary lymphedema, where by skin biopsy. Amputation offers the best there appears to be a genetic susceptibility or chance of survival, but even then most patients element to the disease, may be further divided live less than 3 years. It has been suggested into those cases that are familial (hereditary), that lymphedema leads to an impairment where typically the only abnormality is lym- 117

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Table 10.5. Lymphangiographic classification of primary lymphedema Congenital hyperplasia Distal obliteration Proximal obliteration (10%) (80%) (10%) Age of onset Congenital Puberty (praecox) Any age Sex distribution Male > female Female > male Male = female Extent Whole leg Ankle, calf Whole leg, thigh only Laterality Uni = bilateral Often bilateral Usually unilateral Family history Often positive Often positive No Progression Progressive Slow Rapid Response to compression Variable Good Poor therapy Comments Lymphatics are increased Absent or reduced distal There is obstruction at the in number, although superficial lymphatics; level of the aortoiliac or functionally defective; also termed aplasia or inguinal nodes; if associated there is usually an hypoplasia with distal dilatation, the increased number of patient may benefit from lymph nodes; may have lymphatic bypass chylous ascites, operation; other patients chylothorax, and have distal obliteration as protein-losing well enteropathy

phedema and there is a family history, and those autosomal-dominant manner with incomplete cases that are syndromic, where the lym- (about 50%) penetrance. In some families, the phedema is only one of several congenital condition may be related to abnormalities in the abnormalities and is either inherited or spo- gene coding for a vascular endothelial growth radic. Syndromic lymphedema may be sporadic factor (VEGF) on chromosome 5. The disease is and chromosomal [Turner’s (XO karyotype), characterized by brawny lymphedema of both Klinefelter’s (XXY), Down (trisomy 21) syn- legs (and sometimes the genitalia, arms, and drome], or clearly inherited and related to an face) that develops from birth or before puberty. identified or presumed single gene defect The disease has been associated with a wide [lymphedema-distichiasis (autosomal domi- range of lymphatic abnormalities on lymphan- nant)], or of uncertain genetic etiology (yellow- giography. Meige’s disease is similar to Milroy’s nail and Klippel-Trenaunay-Weber syndromes). disease except the lymphedema generally devel- Familial (hereditary) lymphedema can be ops between puberty and middle age (50 years). difficult to distinguish from nonfamilial lym- It usually affects one or both legs but may phedema because a reliable family history may involve the arms. Some, but not all, cases appear be unobtainable, the nature of the genetic pre- to be inherited in an autosomal-dominant disposition is unknown, and the genetic manner. Lymphangiography generally shows susceptibility may translate into clinical disease aplasia or hypoplasia. only in the presence of certain environmental Lymphedema congenita (onset at or within 2 factors. Although the distinction may not years of birth) is commoner in males, more directly affect treatment, the patients are often likely to be bilateral and to involve the whole leg. concerned lest they be passing on the disease Lymphedema praecox (onset from 2 to 35 years) to their children. Two main forms of familial is three times commoner in females, has a peak (hereditary) lymphedema are recognized: incidence shortly after menarche, is three times Noone-Milroy (type I) and Letessier-Meige more likely to be unilateral than bilateral, and (type II). It is likely that both eponymous dis- usually only extends to the knee. Lymphedema eases overlap and represent more than a single tarda develops, by definition, after the age of 35 disease entity and genetic abnormality. Milroy’s years and is often associated with obesity, with disease is estimated to be present in 1 in 6000 lymph nodes being replaced by fibrofatty tissue. live births and is probably inherited in an The cause is unknown. Lymphedema develop- 118

VASCULAR SURGERY ing for the first time after 50 years should and its progression slowed, by the wearing of prompt a thorough search for underlying shoes. (pelvic, genitalia) malignancy. It is worth noting Lymphangitis and lymphadenitis can cause that, in such patients, lymphedema often com- lymphatic destruction that predisposes to mences proximally in the thigh rather than lymphedema complicated by further acute distally. inflammatory episodes (AIEs). Interestingly, in such patients lymphangiography has revealed Secondary Lymphedema abnormalities in the contralateral, unaffected limb, suggesting an underlying, possibly inher- This is the most common form of lymphedema. ited, susceptibility. Lymphatic and lymph node There are several well-recognized causes, in- destruction by tuberculosis is also a well- cluding infection, inflammation, neoplasia, and recognized cause of lymphedema, especially in trauma. developing countries. Filariasis is the commonest cause of lym- Treatment (surgery, radiotherapy) for breast phedema worldwide, affecting up to 100 million carcinoma is probably the commonest cause of individuals. It is particularly prevalent in Africa, lymphedema in developed countries but is India, and South America, where 5% to 10% decreasing in incidence as surgery becomes of the population may be affected. The vivipa- more conservative. Lymphoma may present rous nematode Wucheria bancrofti, whose only with lymphedema, as may malignancy of the host is humans, is responsible for 90% of cases pelvic organs and external genitalia. Kaposi’s and is spread by the mosquito. The disease is sarcoma developing in the course of human associated with poor sanitation. The parasite immunodeficiency virus (HIV)-related illness enters lymphatics from the blood and lodges may cause lymphatic obstruction and is a in lymph nodes, where it causes fibrosis and growing cause of lymphedema in certain parts obstruction, due partly to direct physical of the world. damage and partly to the immune response of It is not unusual for patients to develop the host. Proximal lymphatics become grossly chromic localized or generalized swelling fol- dilated with adult parasites. The degree of lowing trauma. The etiology is often multifacto- edema is often massive, in which case it is rial and includes disuse, venous thrombosis, termed elephantiasis. Immature parasites and lymphatic injury or destruction. Degloving (microfilariae) enter the blood at night and can injuries and burns are particularly likely to be identified on a blood smear, a centrifuged disrupt dermal lymphatics. Tenosynovitis can specimen of urine, or in lymph itself. A com- also be associated with localized subcutaneous plement fixation test is also available and lymphedema, which can be a cause of trouble- is positive in present or past infection. some persistent swelling following ankle and Eosinophilia is usually present. Diethylcarba- wrist sprains and repetitive strain injury. mazine destroys the parasites but does not It is important to appreciate the relationship reverse the lymphatic changes, although there between lymphedema and CVI. As both condi- may be some regression over time. Once the tions are relatively common and often coexist in infection has been cleared, treatment is as for the same patient, it can be difficult to unravel primary lymphedema. Public health measures which components of the patient’s symptom to reduce mosquito breeding, protective cloth- complex are due to each pathology. There is no ing, and mosquito netting may be usefully doubt that superficial venous thrombophlebitis employed to combat the condition. (SVT) and DVT can both lead to lymphatic Endemic elephantiasis (podoconiosis) is destruction and secondary lymphedema, espe- common in the tropics and affects more than cially if recurrent. Lymphedema is an important 500,000 people in Africa. The barefoot cultiva- contributor to the swelling of the postphlebitic tion of soil composed of alkaline volcanic rocks syndrome. It has also been suggested that lym- leads to destruction of the peripheral lymphat- phedema can predispose to DVT and possibly ics by particles of silica, which can be seen in SVT through immobility and AIEs. Certainly, macrophages in draining lymph nodes. Plantar tests of venous function (duplex ultrasonogra- edema develops in childhood and rapidly phy, plethysmography) are frequently abnormal spreads proximally. The condition is prevented, in patients with lymphedema. 119

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It is not uncommon to see patients (usually features. In patients with severe, atypical, and women) with lymphedema in whom a duplex multifactorial swelling, investigations may help ultrasound scan has revealed superficial reflux confirm the diagnosis,inform management,and (such reflux is present subclinically in up to a provide prognostic information. A full blood third of the adult population).Although isolated count, urea and electrolytes, creatinine, liver superficial venous reflux rarely, if ever, leads function tests, chest radiograph, and blood to limb swelling, such patients are frequently smear for microfilariae may be indicated. Direct misdiagnosed as having venous rather than lymphangiography involves the injection of lymphedema, and mistakenly subjected to VV contrast medium into a peripheral lymphatic surgery. Not only does such surgery invariably vessel and subsequent radiographic visualiza- fail to relieve the swelling, it usually makes it tion of the vessels and nodes. It remains the gold worse as saphenofemoral and saphenopopliteal standard for showing structural abnormalities ligation, together with saphenous stripping, of larger lymphatics and nodes. However, it can compromise still further the drainage through be technically difficult, is unpleasant for the the subcutaneous lymph bundles (which follow patient, may cause further lymphatic injury, the major superficial veins) and draining and has largely become obsolete as a routine inguinal and popliteal lymph nodes. method of investigation. Indirect lymphangiog- Rheumatoid and psoriatic arthritis (chronic raphy involves the intradermal injection of inflammation and lymph node fibrosis), contact water-soluble nonionic contrast into a web dermatitis,snake and insect bites,and retroperi- space, from where it is taken up by lymphatics toneal fibrosis are all rare but well-documented and then followed radiographically. It shows causes of lymphedema. Pretibial myxedema is distal lymphatic but not normally proximal due to the obliteration of initial lymphatics by lymphatics and nodes. Isotope lympho- mucin. Factitious lymphedema is caused by scintigraphy has largely replaced lymphangiog- application of a tourniquet (a “rut” and sharp raphy as the primary diagnostic technique cut-off is seen on examination) or “hysterical” in cases of clinical uncertainty. Radioactive disuse in patients with psychological problems. technetium–labeled protein or colloid particles Generalized or localized immobility due to any are injected into an interdigital web space and cause leads to chronic limb swelling that can specifically taken up by lymphatics, and serial be misdiagnosed as lymphedema. Examples radiographs are taken with a gamma camera. include the elderly person who spends all day The technique provides a qualitative measure of (and sometimes all night) sitting in a chair lymphatic function rather than quantitative (armchair legs), the hemiplegic stroke patient, function or anatomical detail. A single axial and the young patient with multiple sclerosis. computed tomography (CT) slice through the Lipedema presents almost exclusively in mid-calf has been proposed as a useful diag- women and comprises bilateral, usually sym- nostic test for lymphedema (coarse, nonen- metrical, enlargement of the legs and, some- hancing, reticular honeycomb pattern in an times, the lower half of the body due to the enlarged subcutaneous compartment), venous abnormal deposition of fat. It may or may not edema (increase volume of the muscular com- be associated with generalized obesity. There partment), and lipedema (increased subcuta- are a number of features that help to differ- neous fat). Computed tomography can also be entiate the condition from lymphedema, but used to exclude pelvic or abdominal mass lipedema may coexist with other causes of limb lesions. Magnetic resonance imaging (MRI) can swelling. It has been proposed that lipedema provide clear images of lymphatic channels and results from, or at least is associated with, fatty lymph nodes, and can be useful in the assess- obliteration of lymphatics and lymph nodes. ment of patients with lymphatic hyperplasia. It can also distinguish venous and lymphatic Investigation causes of a swollen limb. In cases where malignancy is suspected, samples of lymph It is usually possible to diagnose and manage nodes may be obtained by fine-needle aspira- lymphedema purely on the basis of the history tion, needle core biopsy, or surgical excision. and examination,especially when the swelling is Skin biopsy will confirm the diagnosis of mild and there are no apparent complicating lymphangiosarcoma. 120

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Management that physical therapy can be highly effective in reducing swelling, its general acceptance Ideally, a multiprofessional team comprising and practice has been hampered by a lack of physical therapists, nurses, orthotists, physi- proper research and confusing terminology. cians (dermatologists, oncologists, palliative The current preferred term is decongestive lym- care specialists), surgeons, and social services phedema therapy (DLT) and comprises two should deliver the care. Although surgery itself phases. The first is a short intensive period of has a very small role, surgeons (especially breast therapist-led care, and the second is a mainte- and vascular) are frequently asked to oversee nance phase where the patient uses a self-care the management of these patients. Early regimen with occasional professional interven- diagnosis and institution of management are tion. The intensive phase comprises skin care, essential because at that stage relatively simple manual lymphatic drainage (MLD), multilayer measures can be highly effective and will lymphedema bandaging (MLLB), and exercises. prevent the development of disabling late-stage The length of intensive treatment depends on disease, which is extremely difficult to treat. the disease severity, the degree of patient com- There is often a latent period of several years pliance, and the willingness and ability of between the precipitating event and the onset of the patient to take more responsibility for the lymphedema. The identification, education, and maintenance phase. However, weeks rather treatment of such at-risk patients can slow than months should be the goal. down, even prevent, the onset of disease. In The patient must be carefully educated in the patients with established lymphedema, the principles and practice of skin care. The patient three goals of treatment are to relieve of pain, should inspect the affected skin daily, with reduce swelling, and prevent the development of special attention paid to skin folds where mac- complications. eration may occur. The limb should be washed On initial presentation 50% of patients with daily, the use of bath oil (e.g., balneum) is rec- lymphedema complain of significant pain. The ommended as a moisturizer, and the limb must pain is usually multifactorial, and its severity be carefully dried afterward.A hair drier, on low and underlying cause(s) vary depending on the heat, is more effective and hygienic, and less etiology of the lymphedema. For example, traumatic, than a towel. If the skin is in good following treatment for breast cancer, pain condition, daily application of a bland emollient may arise from the swelling itself, radiation and is recommended to keep the skin hydrated. If surgery induced, nerve (brachial plexus and the skin is dry and flaky, then a bland ointment intercostobrachial nerve), bone (secondary [e.g., 50/50 white soft paraffin/liquid paraffin deposits, radiation necrosis) and joint disease (WSP/LP)] should be used twice daily, and if (arthritis, bursitis, capsulitis), and recurrent there is marked hyperkeratosis, then a kera- disease. The detailed treatment of such patients tolytic agent such as 5% salicylic acid can be is beyond the scope of this chapter but involves added. Many commercially available soaps, the considered use of nonopioid and opioid creams, and lotions contain sensitizers, and, as analgesics, corticosteroids, tricyclic antidepres- patients with lymphedema are highly suscepti- sants, muscle relaxants, antiepileptics, nerve ble to contact dermatitis (eczema), are best blocks, physiotherapy, adjuvant anticancer ther- avoided.Apart from causing intense discomfort, apies (chemo-, radio-, hormonal therapy), as eczema acts as an entry point for infection. well as measures to reduce swelling if possible. Management comprises avoidance of the aller- In patients with non–cancer-related lym- gen (patch testing may be required) and topical phedema, the best way to reduce pain is to corticosteroids. Fungal infections are common, control swelling and prevent the development of difficult to eradicate, and predispose to AIEs. complications. Chronic application of antifungal creams leads Physical therapy for lymphedema comprising to maceration, and it is better to use powders bed rest, elevation, bandaging, compression in shoes and socks. Ointment containing 3% garments, massage, and exercises was first benzoic acid helps prevent athlete’s foot and can described at the end of the 19th century, and be used safely over long periods.Painting at-risk through the 20th century various eponymous areas with an antiseptic agent such as eosin may schools developed.Although there is little doubt be helpful. Lymphorrhea is uncommon but 121

CHRONIC VENOUS INSUFFICIENCY,VARICOSE VEINS, LYMPHEDEMA,AND ARTERIOVENOUS FISTULAS extremely troublesome. Management comprises However, the sub-bandage pressure does not emollients, elevation, compression, and some- alter greatly in response to changes in limb cir- times cautery under anesthesia. cumference consequent upon muscular activity Apart from lymphangiosarcoma, AIEs are and posture. By contrast short-stretch bandages probably the most serious complications of exert support through the production of a semi- lymphedema and frequently lead to emergency rigid casing, where the resting pressure is low hospital admission. About 25% of primary and but changes quite markedly in response to 5% of secondary lymphedema patients are movement and posture. affected. The AIEs start rapidly, often without It is generally believed that nonelastic MLLB warning or precipitating event, with tingling, is preferable (and arguably safer) in patients pain, and redness of the limb. Patients feel viral, with severe swelling during the intensive phase and severe attacks can lead to the rapid onset of of DLT, whereas compression (hosiery, sleeves) fever, rigors, headache, vomiting, and delirium. is preferable in milder cases and during the Patients who have suffered previous attacks can maintenance phase. Whether the aim is to usually predict the onset, and many learn to provide support or compression, the pressure carry antibiotics with them and self-medicate at exerted must be graduated (100% ankle/foot, the first hint of trouble. This may stave off a 70% knee, 50% mid-thigh, 40% groin), and the full-blown attack and prevent the further lym- adequacy of the arterial circulation must be phatic injury that each AIE causes. It is rarely assessed. As it is rarely possible to feel pulses in possible to isolate a responsible bacterium, but the lymphodematous limb, noninvasive assess- the majority are presumed to be streptococcal ment of ABI using a handheld Doppler ultra- or staphylococcal in origin. The diagnosis is sound device is usually necessary. The details of usually obvious but dermatitis, throm- MLLB are beyond the scope of this chapter; bophlebitis, and DVT are in the differential. however, it is highly skilled and in order to be Benzyl (intravenous) or phenoxymethyl (oral) effective and safe, it needs to be applied by a penicillin, and flucloxacillin (or clindamycin in specially trained therapist. It is also extremely severe attacks), are the antibiotics of choice and labor intensive, needing to be changed daily. should be given for 2 weeks. Rest reduces lym- Compression garments form the mainstay of phatic drainage and the spread of infection, management in most clinics. The control of elevation reduces the edema, and heparin pro- lymphedema requires higher pressures (30 to 40 phylaxis reduces the risk of DVT. Co-amoxiclav mmHg in the arm, 40 to 60mmHg in the leg) can be taken by patients who self-medicate. The than are typically used to treat CVI. The patient use of long-term prophylactic antibiotics is not should put the stocking on first thing in evidence-based but is probably reasonable in the morning before rising. It can be difficult patients who suffer frequent attacks. However, to persuade patients to comply. Donning the benefits of scrupulous compliance with lymphedema-grade stockings is difficult, and physical therapy and skin care cannot be under- many patients find them intolerably uncomfort- estimated. able, especially in warm climates. Furthermore, Several different techniques of MLD have although intellectually they understand the been described and the details are beyond the benefits, emotionally they may find wearing scope of this chapter. However, they all aim to them presents a greater body image problem evacuate fluid and protein from the ISF space than the swelling itself. and stimulate lymphangion contraction. Thera- Enthusiasm for pneumatic compression pists should perform MLD daily; they should devices has waxed and waned. Unless the device also train the patient or caregiver to perform a being used allows the sequential inflation of simpler, modified form of massage termed multiple chambers up to 50mmHg, it will prob- simple lymphatic drainage (SLD). In the inten- ably be ineffective for lymphedema. Patient sive phase, SLD supplements MLD, and once the benefit is maximized and complications mini- maintenance phase is entered, SLD will carry on mized if these devices are used under the direc- as daily massage. tion of a physical therapist as part of an overall Elastic bandages provide compression, pro- package of care. duce a sustained high resting pressure, and Lymph formation is directly proportional to compress more as limb swelling reduces. arterial inflow, and 40% of lymph is formed 122

VASCULAR SURGERY within skeletal muscle. Vigorous exercise, espe- the ileal mucosal patch (Kinmonth), and, more cially if it is anaerobic and isometric, tends to recently, direct lymphovenous anastomosis. exacerbate lymphedema, and patients should The procedures are technically demanding, not be advised to avoid prolonged static activities, without morbidity, and there is no controlled for example, carrying heavy shopping bags or evidence to suggest that these procedures prolonged standing. By contrast, slow rhythmic produce an outcome superior to the best isotonic movements (e.g., swimming) and mas- medical management alone. Limb reduction sage increase venous and lymphatic return procedures are indicated when a limb is so through the production of movement between swollen that it interferes with mobility and skin and underlying tissues (essential to the livelihood. These operations are not cosmetic in filling of initial lymphatics) and augmentation the sense that they do not create a normally of the muscle pumps. Exercise also helps to shaped leg and are usually associated with maintain joint mobility. Patients who are unable significant scarring. Four operations have been to move their limbs benefit from passive exer- described: cises. When at rest, the lymphedematous limb 1. Sistrunk: A wedge of skin and subcuta- should be positioned with the foot/hand above neous tissue is excised and the wound the level of the heart. A pillow under the mat- closed primarily. This is most commonly tress or blocks under the bottom of the bed employed to reduce the girth of the thigh. encourage the swelling to go down overnight. There are considerable, and scientifically 2. Homan: Skin flaps are elevated; subcuta- inexplicable, differences in the use of specific neous tissue is excised from beneath the drugs for venous disease and lymphedema flaps, which are then trimmed to size to between different countries. The benzpyrenes accommodate the reduced girth of the are a group of several thousand naturally occur- limb and closed primarily. This is the most ring substances, of which the flavonoids have satisfactory operation for the calf. The received the most attention. Enthusiasts argue main complication is skin flap necrosis. that a number of clinical trials have shown There must be at least 6 months between benefit from these compounds, which are operations on the medial and lateral sides purported to reduce capillary permeability, of the limb, and the flaps must not pass improve microcirculatory perfusion, stimulate the midline. This procedure has also been interstitial macrophage proteolysis, reduce ery- used on the upper limb but is contraindi- throcyte and platelet aggregation, scavenge free cated in the presence of venous obstruc- radicals, and a exert an antiinflammatory effect. tion or active malignancy. Detractors argue that the trials are small and 3. Thompson: One denuded skin flap is poorly controlled, with short follow-up and soft sutured to the deep fascia and buried end points, and that any benefits observed can beneath the second skin flap (the so-called be explained by a placebo effect. Diuretics are of buried dermal flap). This procedure has no value in pure lymphedema.Their chronic use become less popular as pilonidal sinus for- is associated with side effects including elec- mation is common, the cosmetic result is trolyte disturbance and should be avoided. no better than that obtained with the Homan’s procedure, and there is no evi- Surgery dence that the buried flap establishes any new lymphatic connections within the Surgery benefits only a small minority of deep tissues. patients with lymphedema. Operations fall into 4. Charles: This operation was initially two categories: bypass procedures and reduc- designed for filariasis and involved exci- tion procedures. The rare patient with proximal sion of all the skin and subcutaneous ilioinguinal lymphatic obstruction and normal tissues down to the deep fascia with cover- distal lymphatic channels might benefit, at least age using split skin grafts. This leaves a in theory, from lymphatic bypass. A number of very unsatisfactory cosmetic result, and methods have been described including the graft failure is not uncommon. However, it omental pedicle, the skin bridge (Gillies), anas- does enable the surgeon to reduce greatly tomosing lymph nodes to veins (Neibulowitz), the girth of a massively swollen limb. 123

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Arteriovenous Fistulas coloration and a lump. If arterial, it is typically firm, pulsates, and is associated with a thrill and Classification a murmur and sometimes pulsatile draining veins. If primarily venous, it is soft and com- Arteriovenous fistulas (AVFS) are broadly pressible, and reduces in size and enlarges upon classified into congenital and acquired. elevation and dependency, respectively. Acquired fistulas may be traumatic, iatrogenic, or associated with malignancy, aneurysmal Hemangiomas disease, and infection. These are not considered further. Congenital AVFs are further classified Hemangiomas present at or within a few weeks as hemangiomas or malformations. The former of birth. They are said to be present in 10% are characterized by endothelial hyperplasia, of Caucasian children on their first birthday, to are not present at birth, and grow in early child- be three times commoner in girls, to be multi- hood, but in 90% of cases involute by the age ple in 20%, and to affect the head and neck of 5 to 10 years. The latter exhibit normal (60%), trunk (25%), and extremities (10%). If endothelial cell kinetics, are always preset at superficial, they are bright (strawberry nevus), birth, grow and continue to grow with the child, and if deep dark (cavernous hemangioma), red. and may enlarge dramatically at puberty or in They are firm and rubbery and cannot be pregnancy. Whenever vascular lesions appear emptied of blood on compression or elevation. and grow rapidly, it is important to exclude After an initial phase of rapid growth, they malignancy. Malformations may be high flow begin to involute at about 6 to 12 months of (predominantly cardiac and great vessel anom- age when the red color turns to purple, alies) or low flow (arterial, venous, lymphatic, or gray/while flecks appear, the lesion becomes mixed). The processes leading to the develop- softer, and the overlying skin wrinkles. Resolu- ment of the mature vascular tree are largely tion is typically completed in 50% at 5 years, unknown, but presumably congenital fistulas 70% at 7 years, and 90% or more by 10 years. represent a localized disorder of vessel forma- Apart from cosmetic concerns there may be tion. Occasionally they may be familial, and ulceration and bleeding. On the face they may some abnormalities have been mapped to block vision, and depending on where they are certain chromosomal loci. sited may cause mass effects. Large heman- giomas involving internal organs may cause heart failure and anemia. Symptoms and Signs The clinical presentations are protean and Diagnosis and Investigation depend on the nature of the lesion, anatomical The diagnosis can usually be made on clinical site, size, and flow. examination. Handheld Doppler helps to con- firm if there is an arterial component, and DU Malformations provides more detailed anatomical and func- tional information. In particular, DU permits Although malformations are present at birth, detailed assessment of the venous system in they do not usually become symptomatic, and patients with Klippel-Trenaunay syndrome even go unnoticed, until later at life. They typi- where the deep venous system may be hypoplas- cally present at puberty or during pregnancy or tic or even absent, having been replaced by an following trauma to the part. There is usually abnormal laterally placed venous malformation. an obvious swelling and discoloration, and Duplex ultrasound has largely replaced venog- there may be limb enlargement. Adults typically raphy. Phleboliths may be seen on plain x-rays present with a lump,VVs, (ischemic) ulceration, and are only usually seen in venous lesions. bleeding, or an inequality in limb length. That Magnetic resonance imaging, rather than CT, is which is visible is often the “tip of the iceberg,” now regarded as the definitive investigation for and the deep component may cause pain, pres- assessing the extent of AVF. Angiography is sure on local strictures, organ dysfunction, and performed only where there is an intention to internal bleeding. On examination there is dis- treat radiologically. 124

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Management tion (arterial lesions) or by direct injection (venous lesions), usually under general anesthe- Management is complex,multidisciplinary (vas- sia. This is a highly skilled and specialized cular, plastic, maxillofacial, and orthopedic sur- branch of , and great geons, interventional radiologist, cardiologist), care must be taken to avoid collateral damage. difficult, and highly tailored to the individual Extremities are particularly vulnerable. Surgical patient. Many patients (and parents) simply skeletonization of the arterial inflow to the require reassurance, and in general it pays to be lesion is now avoided,as recurrence is inevitable as conservative as possible. Only 10% of heman- and such intervention prevents radiological giomas fail to resolve spontaneously and many intervention. Strong indications for interven- malformations remain asymptomatic. Pallia- tion are hemorrhage, distal ischemia due to tion, not cure, is the principal aim, and it is steal, and ulceration due to ischemia or venous important to ensure that the treatment is not hypertension. worse than the disease. Venous lesions may be treated with compression bandaging and hosiery. A small minority of patients are suit- References able for excisional surgery. Complete excision is rarely possible, and usually the aim is to remove Cornu-Thenard A, Boivin P, Baud JM, De Vincenzi I, the most symptomatic part. Such surgery can be Carpentier PH. (1994) J Dermatol Surg Oncol 20:318–26. difficult and bloody, and recurrence is common. Dwerryhouse S, Davies B, Harradine K, Earnshaw JJ. (1999) For these reasons, most patients are treated J Vasc Surg 29:589–92. radiologically either by transcatheter emboliza- Szuba A, Rockson SG. (1997) Vasc Med 2:321–6. 11 Vascular Trauma Kathleen J. Ozsvath, R. Clement Darling III, Laila Tabatabai, Sacha Hamdani, Alun H. Davies, and Meryl Davis

Trauma is the leading cause of death in patients try was established during the Vietnam War; under the age of 44 in the United States. North surgeons were able to document and analyze the American trauma centers have an incidence of long-term management and outcome of vascu- penetrating trauma of 35% as compared with lar trauma (Rich and Hughes, 1969). The 5% to 8% in Europe, the difference being ex- significantly improved long-term results of vas- plained by the higher rate of weapon-related cular repair were attributed to faster evacuation crimes in North America.The treatment of trau- of casualties within 3 hours of injury, thereby matic vascular injuries today is based on prin- allowing surgeons to treat injuries that had pre- ciples gained during the military conflicts of the viously been otherwise fatal. Operations were 20th century; previously treatment of vascular performed by experienced surgeons using auto- injuries was limited to the staunching of bleed- logous vein grafts. ing by cautery, compression, and ligature. The The rise of civilian trauma in the United concept of repair was documented in anecdotal States has resulted in surgeons becoming more reports only. William Hunter in 1759 recounts adept and experienced at dealing with vascu- the first successful vascular repair on a brachial lar injuries (Mattox et al., 1989). Penetrating artery using a farrier’s stitch. injuries have been the number one cause of Reports of vein grafting were available in vascular trauma in both urban and rural com- the early 20th century; however, these tech- munities, whereas blunt trauma has accounted niques were not suitable for the injuries en- for approximately 50% of vascular injuries, countered during World War I, in which the most commonly secondary to road traffic amputation rate was noted to be 72.5%. In 1946 accidents. DeBakey and Simeone published a review of Regardless of the etiology of the vessel injury, World War II experiences with vascular surgery. the essential principles of treatment are emer- They concluded that ligation was “of stern gency resuscitation at the scene, triage and necessity,” required to control hemorrhage; rapid transport to an appropriate hospital, vig- attempts at vascular repair were superior to orous resuscitation, diagnosis, and definitive ligation and led to an amputation rate of surgery. Ideally, vascular injuries should be 49%. treated by surgeons with expertise in vascular The application of vessel reconstruction in reconstruction and trauma, in an environment the Korean War, despite the mean lag time of with the necessary ancillary support services to over 6 hours between injury and repair, reduced allow the best results. the lower limb amputation rate to 13% (Hughes, This chapter reviews the workup and treat- 1959); a comparable figure was achieved during ment of traumatic vascular injuries involving the Vietnam War. The Vietnam Vascular Regis- the head and neck, chest, abdomen, and extrem-

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VASCULAR SURGERY ities, and discusses the approach to iatrogenic Diagnosis injuries and the endovascular treatment of vas- cular injuries. The clinical manifestations of vascular injury are divided into hard and soft signs (Table 11.1). The management of penetrating limb trauma in the presence of one hard sign is exploration in Mechanisms of Injury the operating room. In blunt trauma, closed head injuries, spinal damage, and cervical and Vascular injuries can be divided into penetrat- brachial plexus injuries may complicate the ing and blunt. Penetrating injuries include stab- clinical findings; a careful neurological exami- bing and gunshot wounds. Stab wounds are nation is mandatory. usually clean with minimal soft tissue injury; Clinical examination in blunt and complex however, in the neck and upper limb concurrent penetrating trauma may be unreliable, and nerve damage must also be suspected. trauma centers advise early angiography. The Gunshot wounds are classified according to role of duplex ultrasound in vascular trauma is the bullet velocity. Low velocity bullets have less clear; currently it has a major role in the a velocity of less than 250m/s, whereas 750 to diagnosis of occult vascular injuries and in 900m/s represents the speed of high-velocity postoperative assessment.Doppler arterial pres- bullets. Low-velocity bullets injure the tissue sure index (API) is a useful tool. It is the systolic through which they pass, whereas high-velocity arterial pressure in the injured extremity bullets create a cavitational effect, thereby caus- divided by the arterial pressure in a noninjured ing a suctional effect contaminating the entire arm. A result of <0.90 has been found to have a wound. If a high-velocity bullet strikes bone, sensitivity of 95% and specificity of 97% for there is extensive comminution with a large exit major arterial injury (Johansen et al., 1991). wound. Shotgun injuries particularly to a limb Once the diagnosis of major vascular injury can cause vascular damage at several levels. has been made, the majority of patients require Bombs, mines, and rocket-propelled grenades exploration and repair. The principles of emer- produce complex injuries that frequently result gency vascular repair are to control bleeding in amputation. and prevent limb ischemia. Hemorrhage is Blunt vascular trauma is often caused by usually apparent, but ischemia may be insidious deceleration in road traffic accidents and is fre- and must be sought. Time is paramount; it is quently associated with other injuries. Femoral generally accepted that more than 6 to 8 hours shaft fractures and fracture dislocations of the of warm ischemia time makes limb survival knee carry a 10% to 40% incidence of vascular unlikely. If there is significant concurrent nerve injury. It is important to realize that although damage, then limb reconstruction may not be the artery can remain intact, intimal damage appropriate and amputation should be per- with concomitant thrombosis risk can occur. formed. The input of multidisciplinary teams is Blunt trauma to the upper limb is often asso- vital to ensure optimal treatment. ciated with avulsion injuries to the brachial plexus. Extensive crush injuries to the limbs are associated with a poor prognosis due to soft tissue damage and reperfusion injury. Iatrogenic injuries are increasing in inci- Table 11.1. The clinical manifestations of vascular injury are dence as a consequence of invasive procedures. divided into hard and soft signs Cardiological and radiological catheterization cause between 60% and 76% of all iatrogenic Hard signs Soft signs injuries. Orthopedic procedures including joint No pulse Hematoma (small) replacements may cause vascular injury, com- Thrill or bruit History of bleeding at scene monly to the external iliac, common femoral, or Active bleeding Hypotension popliteal arteries.In such cases where iatrogenic Hematoma (large/ Nerve damage expanding) arterial injury is suspected, expeditious referral Distal ischemia to a vascular surgeon must be made. 127

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Vascular Injuries in the Neck Wounds of major vessels are often lethal, and frequently these patients have multiple injuries. This is particularly true in penetrating in- juries of the brachiocephalic vessels, where air- way compromise, hemorrhage, and neurological damage secondary to impaired brain blood flow may occur, along with associated injuries to the III pharynx, esophagus, and brachial plexus. In the neck penetrating trauma is more common than blunt trauma, although vascular injuries caused by blunt trauma can be more difficult to diagnose and treat. Blunt injuries II include steering wheel injuries, deceleration forces, and crushing blows. Injuries to the carotid artery occur in 6% of I penetrating injuries to the neck and make up 22% of all vascular neck injuries, whereas 3% to Figure 11.1. Treatment of vascular injuries in the neck is based 5% of carotid injuries are secondary to blunt on dividing the neck into three zones: zone I is 1cm above the trauma (Demetriades et al., 1996). The mortal- manubrium to include the thoracic outlet, zone II extends from ity rate of patients with penetrating neck vas- the upper limit of zone I to the angle of the mandible,and zone cular trauma is 5% to 20%. Patients presenting III lies between the angle of the mandible and the base of the with obvious signs of penetrating vascular skull. injury (expanding hematoma, pulsatile bleed- ing) should be rapidly explored operatively. Treatment of vascular injuries in the neck is and dissections of the carotid artery who are based on dividing the neck into three zones: otherwise stable may be followed with physical zone I is 1cm above the manubrium including examination and follow-up duplex ultrasound, the thoracic outlet, zone II extends from the because these lesions may resolve without inter- upper limit of zone I to the angle of the man- vention. Venous injuries may be dealt with by dible, and zone III lies between the angle of the ligation. In the unusual circumstance of both mandible and the base of the skull (Fig. 11.1). internal jugular veins having been damaged it is Zone I injuries are best explored through a imperative that one vein be reconstructed. median sternotomy,which can then be extended Patients with blunt carotid artery injuries can superiorly along the anterior border of the ster- be difficult to diagnose due to either other nocleidomastoid muscle as needed. Penetrating distracting injuries or altered mental status. trauma to vessels in zone II can be approached Carotid artery blunt injuries are associated with directly for definitive repair. Zone III injuries a high mortality and poor neurological out- can be difficult to access and sometimes require comes in most patients. subluxation of the mandible or mandibular Mechanisms of blunt carotid artery in- osteotomy. Patients with zone III asymptomatic, juries include hyperextension, direct injury, angiographically documented injuries are now basilar skull fractures, and intraoral injuries. being managed with endovascular stenting or Patients may present with carotid artery dissec- embolization (Feliciano, 2001). tions, thrombosis, pseudoaneurysms, carotid- Arterial defects are repaired with primary cavernous sinus fistulas, or arterial disruption. repair, transposition, patch, or bypass. Patients Carotid artery dissections and thrombosis are found to have an acutely occluded carotid artery treated with anticoagulation. Cogbill et al. are anticoagulated in an effort to prevent clot (1994) reported that two thirds of patients with propagation. Neurologically impaired patients carotid dissections eventually have normal with carotid injuries are aggressively treated studies on follow-up, whereas one third pro- surgically. Patients with small intimal defects gress. Pseudoaneurysms may be treated surgi- 128

VASCULAR SURGERY cally or radiologically depending on their size. bruising, reduced or absent lower limb pulses, Carotid–cavernous sinus fistulas are generally raised jugular venous pressure, and unex- treated by endovascular techniques. Complete plained hypotension. The chest radiograph may disruption of the carotid artery is associated show a widened mediastinum, fracture of the with a high mortality. first or second rib, hemothorax, and thoracic Injury to the vertebral arteries is rare. The spine injury. anatomical location of the injury determines the In stable patients the investigations of choice best operative approach when intervention is are chest radiographs (suggesting great vessel required. Proximal vertebral artery exposure is or aortic injury), spiral computed tomography performed by a transverse supraclavicular inci- (CT) with contrast, angiography, and trans- sion or an anterior cervical incision. The cervi- esophageal echocardiography. cal vertebral artery is best approached through The most common intrathoracic injury an incision along the anterior border of the ster- caused by deceleration involves disruption of nocleidomastoid muscle, and can be extended the descending thoracic aorta at the isthmus. to the posterior auricular area. Once the verte- Sudden death is common, and it is estimated bral artery takes its course from the C2 foramen that 90% die before reaching the hospital; of and enters the skull, the exposure becomes very those who reach the hospital, 25% die within difficult. Ligation or occlusion of the vertebral 24 hours. artery is usually the treatment of choice. Per- Commonly the site of aortic disruption is cutaneous techniques have been successfully distal to the left subclavian artery. Access is employed in managing arteriovenous fistulas, gained via a left posterior thoracotomy with pseudoaneurysms, and occlusions (Halbach . The incidence of et al., 1993). paraplegia is approximately 8%. Recent endolu- minal treatment has been described and shown to be successful with a lower mortality rate. Thoracic Vascular Injuries The subclavian arteries are relatively well protected from blunt trauma. Patients may Thoracic vascular trauma constitutes approxi- present with absent distal pulses, and injury mately 10% of vascular trauma (Bongard et al., should be suspected in patients with a first rib 1990). Although penetrating trauma remains fracture or traction injury to the brachial the most common etiology of thoracic vascular plexus. In stable patients, careful clinical assess- injuries, deceleration injuries and crush injuries ment of the brachial plexus and magnetic reso- can result in major thoracic vascular trauma. nance imaging (MRI) should be performed Injuries to the vessels in the thoracic cavity prior to surgical exploration. can lead to rapid blood loss and hemodynamic Direct repair of the vessel, patch, and pros- collapse; many patients die before reaching thetic or autologous interposition grafts are the hospital. It is often more appropriate to possible choices in repairing aortic and great bypass the nearest hospital and transfer the vessel injuries. Some centers are now opting to patient to a unit able to manage cardiothoracic use endovascular techniques (Ohki et al., 1997). problems. At present this method of treatment should be These patients may require immediate treat- pursued only in institutions with adequate sur- ment for tension pneumothorax or cardiac tam- gical and radiological expertise. ponade. Thoracotomy may be required as an emergency procedure and is usually carried out via a left anterolateral thoracotomy incision Abdominal Vascular Injuries (which can be extended across the sternum) or a posterolateral thoracotomy. Access to carotid One third of patients with vascular trauma pre- arteries and innominate artery can be obtained sent with abdominal vascular injuries. These through a median sternotomy.Middle and distal patients are more commonly victims of pene- subclavian artery injuries can be controlled trating injuries, with mortality rates averaging with infra- and supraclavicular approaches. 50%. Deceleration and compression injuries are Clinical findings suggesting thoracic injury common blunt injuries and may cause damage include external evidence of severe chest to the renal or superior mesenteric arteries and 129

VASCULAR TRAUMA portal vein tributaries. Vessels can be injured patch with autologous or prosthetic material, or by transection or partial transection, or have interposition grafting with prosthetic material. intimal defects causing thrombosis. Major vas- The use of antibiotic-soaked grafts may over- cular injury in the abdomen is often associated come concerns regarding the use of prosthetic with injuries to other intraabdominal organs. Of material in the presence of penetrating injuries. those patients who reach the hospital, the mor- The decision to explore a retroperitoneal tality postsurgery remains high (50% to 70% hematoma depends on the mechanism of injury for aortic injury and 30% to 53% for vena caval and stability of the patient. For a retroperitoneal injury). hematoma caused by blunt trauma, a conser- Resuscitation is based on Advanced Trauma vative approach is advised especially when it Life Support (ATLS) guidelines, with unstable is associated with pelvic fractures. This can patients being transferred promptly to the oper- be addressed by external fixation of the pelvis, ating room (Fig. 11.2). Intrathoracic injuries are angiography, and coil embolization. In contrast associated in up to 25% of patients with gunshot an expanding or pulsatile retroperitoneal wounds of the abdomen. hematoma requires immediate exploration. The assessment of stable patients with intra- Retrohepatic caval injuries are difficult to abdominal pathology has been extensively dis- control and carry a high mortality. Mobilization cussed; ultrasound and CT are the modalities of of the liver with division of the right triangular choice. Angiography in the stable patient with ligament and right thoracotomy with dissection blunt injuries may be useful in documenting of the diaphragm may be required. Bleeding unusual injuries. from the porta hepatis can be controlled by In unstable patients with significant hemor- compression of the hepatic artery and portal rhage, laparotomy should be performed and the vein (Pringle’s maneuver). abdomen packed, and systematic evaluation The mortality rate for patients with of the abdomen undertaken. Large defects in significant superior mesenteric artery (SMA) the gastrointestinal tract should be temporarily injury can be high (58% mortality rate).Injuries controlled with soft bowel clamps to reduce to the proximal SMA are technically challenging contamination. If hemorrhage is not controlled, due to the proximity of the pancreas and the it may be necessary to cross-clamp the proximal presence of multiple short branches. Control of supraceliac aorta via the lesser sac; alternatively the supramesocolic vessels can be obtained by (via the left thorax) the descending thoracic medial visceral rotation via the left paracolic aorta may be cross-clamped. The goal is to gutter. Injuries to the celiac artery and branches obtain proximal and distal control of the hem- may present with an expanding hematoma dis- orrhaging vessels so that repair or ligation can placing the stomach and pancreas forward. quickly be undertaken. Hypothermia and coag- Celiac axis vessels may be ligated if there is ulopathy is a serious risk; therefore, expeditious a patent SMA. Retropancreatic SMA control control is important. Aortic injuries can be may have to be obtained by transection of the repaired with a transverse primary repair, a pancreas.

Resuscitation as per ATLS guidelines

Haemodynamically Haemodynamically Unstable Stable

Figure 11.2. Algorithm for the management of a patient with abdominal trauma. Theatre Ultrasound CT Angiography 130

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Injury or transection of the SMA may require In those patients requiring surgical inter- either autologous or prosthetic bypass. Bowel vention, vessels are repaired by primary repair, viability may be difficult to assess intraopera- interposition grafting, or bypass with vein tively; therefore, second-look laparotomy in (from the uninjured limb) or prosthetic mate- these patients is advisable. rial; 31% of patients with arterial trauma have Inframesocolic vessel injuries can be ap- concomitant venous injuries. Repair of venous proached by mobilizing the small intestines and injuries has been found to improve the outcome transverse colon superiorly. The inferior mesen- of patients with combined arterial and venous teric artery can be ligated in most patients, as injuries (Martin et al., 1994; Pappas et al., collaterals exist that provide adequate blood to 1997). the intestine. Grossly contaminated wounds and massive Access to the inferior vena cava, right renal soft tissue and bone injuries require a multi- vein, suprarenal aorta, and porta may be gained disciplinary team approach to management. by an extended mobilization of the duodenum, Orthopedic injuries should be reduced with head of pancreas, and right colon (Kocher external fixators, and arterial and venous shunts maneuver). The infrarenal aorta is exposed by can be used to minimize the ischemia time. Soft retracting the small bowel to the right and incis- tissue coverage either by extraanatomical by- ing the retroperitoneum from the root of the pass or muscle flaps may be necessary to protect mesocolon to the pelvis. Simple stab wounds to vascular repairs. the aorta may be closed primarily; more exten- Debridement of devitalized tissue is impor- sive injuries may require a prosthetic patch or tant for postoperative wound care. Fasciotomies bypass graft. In the presence of significant con- are also of great importance in those patients tamination, an axillobifemoral bypass may be with extremity injuries who have suffered preferred after ligation of the aorta. Iliac vessel delayed repair, extensive tissue injury, swelling, injuries can be approached via the retroperi- elevated compartment pressures, and prolonged toneum; such injuries carry a high mortality hypotension. The development of compartment (10% to 40%) and morbidity including limb syndrome can lead to myoglobinuria, renal loss. failure, and skeletal muscle necrosis. Renal artery injury may occur after rapid Controversies arise in the presence of exten- deceleration, resulting in acute renal artery sive tissue damage, vascular injuries, and con- thrombosis or laceration. The diagnosis of comitant nerve injuries. Unfortunate patients thrombosis is often made late, and if explored may be facing the future with a viable limb that 12 hours after the injury, renal salvage is often is nonfunctioning and painful after multiple limited. In patients with a functioning kidney operations. These patients may be best served on the opposite side, a “watch and wait” policy with a primary amputation. This is a difficult can be adopted. decision to make, and therefore should be made The control of venous hemorrhage can be only after extensive discussion with the patient difficult. Simple injuries to the inferior vena and family, and after the expertise of the com- cava can be repaired primarily with intermittent bined team has been sought. digital pressure. In severe hemorrhage, ligation Injuries of the subclavian and axillary vessels of the infrarenal vena cava may be necessary; in rarely cause upper extremity ischemia due to contrast, injury to the suprarenal vena cava the rich collateral network at the shoulder. requires reconstruction. Penetrating and blunt injuries can both lead to brachial plexus injuries. Brachial artery injuries below the level of the profunda brachii Extremity Vascular Injuries may not present with ischemia due to the col- lateral supply around the elbow. Isolated injury Experience both with trauma patients and with to the ulnar or radial arteries may be treated noninvasive techniques are paramount in the with ligation in the presence of a complete pal- management of extremity vascular trauma. A mar arch. low threshold for angiography should be main- Injuries to the femoral vessels occur in 70% tained to diagnose ischemia. of all arterial injuries, with penetrating trauma 131

VASCULAR TRAUMA being the most common etiology.In 20% to 35% tissue infection, mycotic aneurysm formation, of cases in which the popliteal artery is injured, and gangrene. the popliteal vein and tibial nerve are also involved. Blunt injuries to the knees leading to posterior dislocation can result in popliteal Endovascular Treatments artery injury in 30% to 40% of patients. Single tibial vessel injury can generally be dealt with by With the emergence and development of endo- ligation; however, if more than one vessel is vascular techniques, arterial trauma is being involved, repair is advocated. treated at some centers with coil embolization, intravascular stent grafts, and covered stent grafts. The use of endovascular techniques has Iatrogenic Vascular Injuries minimized the need for extensive operative dis- sections and anesthesia; this is especially impor- With an increasing use of percutaneous tech- tant in injuries involving vessels difficult to niques, there is also a higher risk of iatrogenic assess. Endovascular techniques are best uti- vascular injuries. In a survey of 10,500 cases lized in institutions equipped and ready to following femoral artery puncture, the in- handle trauma in this fashion. cidence of complications was 0.44% (Dorfman and Cronan, 1991). For cardiac catheterization the incidence was 0.55%, whereas peripheral angiography resulted in a complication rate of Conclusion 0.17%. The most important risk is bleeding, which Improvements in patient transport to a level- may be controlled with direct pressure after a one trauma center combined with prehospital catheter has been removed. Occasionally, surgi- care have allowed patients to present earlier for cal repair is undertaken to repair the punctured treatment. The multidisciplinary team approach vessel; direct repair is adequate in most to the management of these patients has led to instances. Retroperitoneal bleeding is generally better outcomes. self-limiting; however, when the patient has In vascular reconstructive surgery autologous been taking anticoagulants blood or pharmaco- bypasses should be used wherever possible logical products may be required to correct clot- (vein being harvested from the uninjured limb). ting abnormalities. In the event of this not being possible, the newer Pseudoaneurysms can also complicate punc- antibiotic-soaked prosthetic grafts is advocated. tures in 0.5% to 5.5% of diagnostic femoral Interventional radiology with deployment of punctures. Most of these pseudoaneurysms endoluminal stents will continue to develop its thrombose spontaneously. Many false aneur- role in vascular trauma. It is important that vas- ysms respond well to ultrasound-guided com- cular surgeons remain involved in all aspects of pression, which has now been superseded by vascular trauma to facilitate improvements. compression with concomitant injection of procoagulant products. Surgical intervention must be undertaken acutely in the presence of References a femoral neuropathy, hemodynamic instabil- ity, overlying skin necrosis, and extremity Bongard F,Dubrow T,Klein S. (1990) Ann Vasc Surg 4:415–8. ischemia. Cogbill TH, Moore EE, Meissner M, et al. (1994) J Trauma Arteriovenous fistulas usually present late 37:473–9. Demetriades D, Asensio JA,Velmahos G,Thal E. (1996) Surg and complicate up to 2% of cardiac catheteriza- Clin North Am 76:661–83. tions. Although most of these fistulas throm- Dorfman GS, Cronan JJ. (1991) Radiology 178:629–30. bose, a small percentage can lead to congestive Feliciano DV. (2001) World J Surg 25:1028–35. heart failure or limb ischemia requiring either Halbach VV, Higashida RT, Dowd CF, et al. (1993) J Neuro- surg 79:183–91. radiological or surgical intervention. Hughes CW. (1959) Milit Med 124:30–46. Vascular injury secondary to intraarterial Johansen K, Lynch K, Paun M, Copass M. (1991) J Trauma injection of drugs can lead to extensive soft 31:515–9; discussion 519–22. 132

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Martin LC, McKenney MG, Sosa JL, et al. (1994) J Trauma Pappas PJ, Haser PB, Teehan EP, et al. (1997) J Vasc Surg 37:591–8; discussion 598–9. 25:398–404. Mattox KL, Feliciano DV, Burch J, et al. (1989) Ann Surg Rich NM, Hughes CW. (1969) Surgery 65:218–26. 209:698–705; discussion 706–7. Ohki T,Veith FJ, Marin ML, Cynamon J, Sanchez LA. (1997) Semin Vasc Surg 10:272–85. 12 Complications in Vascular Surgery Jeremy S. Crane, Nicholas J.W. Cheshire, and Gilbert R. Upchurch, Jr.

Complications in vascular surgery are often life perioperative and postoperative occur, leading threatening. However, with treatment options to myocardial ischemia. Naturally, the type of for vascular disease ever widening, patient surgery is related to cardiac risk; procedures selection for operative procedures is governed associated with blood pressure and cardiac not only by evidence-based treatment options rhythm changes with significant blood loss are but also by immediate and long-term compli- at high risk (e.g., aortic aneurysm repair), cations. The major impact complications of whereas carotid endarterectomy carries moder- vascular surgery, in particular long-term com- ate cardiac risk. plications, have on patient quality of life, inpa- Patients at high risk of a coronary event may tient hospital costs, psychological problems, be considered for preoperative stress testing and health care resources cannot be stressed or may be directly referred for coronary angio- enough. graphy with possible coronary bypass or A useful working definition of a vascular angioplasty prior to vascular surgery. Cardiac surgical complication is a procedure-related complications influence the outcome of vascu- adverse event that harms a patient (Table 12.1). lar surgery to such an extent that the existence Many of the same complications that are ubiq- of cardiac disease may lead the vascular surgeon uitous in general surgery are pertinent to vas- to pursue an alternative surgical technique, cular surgery. such as extraanatomical bypass to treat aortic disease, or to cancel vascular surgical interven- tion altogether. Cardiac and Pulmonary The magnitude of the effect of coronary disease following vascular surgery is such that Complications even 2 years following vascular surgery, 19% of patients experience a late cardiac event The most important cause of mortality and (Krupski, 1993). morbidity after major peripheral vascular sur- In addition, many elderly vascular surgery gery is perioperative cardiac complications. patients have a degree of underlying pulmonary Atherosclerosis is a systemic arterial vascular disease. Therefore, postoperative respiratory disorder typically involving multiple vascular complications are exceedingly common after territories in the same patient. Accordingly, major vascular surgery. Predisposing patient coronary artery disease is the most frequently risk factors that may give rise to respiratory associated vascular territory affected in patients problems include advancing age,cigarette smok- with peripheral arterial disease. Consequently, ing, and the presence of chronic obstructive cardiac manifestations of atherosclerosis in the pulmonary disease. Predisposing procedure-

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Table 12.1. Classification of complications by outcome Complications of Arterial Minor complications No therapy, no consequence Reconstruction Nominal therapy, no consequence; includes overnight admission for observation only Vascular surgical complications arising specifi- Major complications cally from peripheral arterial reconstruction Requires therapy, minor hospitalization (<48 hours) are becoming more prevalent. This is due to Requires major therapy, unplanned increase in level of increasing numbers of operations being under- care, prolonged hospitalization (>48 hours) taken, with up to 50,000 patients being admitted Permanent adverse sequelae annually to hospitals in the United Kingdom for Death treatment of lower limb ischemia. Due to the growing aging population coupled with the ever-expanding role of vascular surgery, sur- geons will be faced with increasing numbers of complications following lower extremity revas- cularization. As these complications may be life specific risk factors include emergency proce- or limb threatening, treating these complica- dures, lengthy general anesthesia, thoracic or tions is one of the most significant challenges upper abdominal incisions, massive blood facing the contemporary vascular surgeon. transfusions, and a postoperative period of pro- Specific complications associated with peri- longed immobility. Similar to cardiac disease, pheral arterial reconstructions usually occur screening for pulmonary dysfunction preope- within predictable time frames, and can be ratively can reduce postoperative respiratory classified as immediate, early, intermediate, or morbidity. A thorough history to ascertain late (Table 12.2). For the purpose of this chapter, whether the patient suffers from dyspnea on immediate complications refer to those events exertion or has significant sputum produc- occurring intraoperatively or within the first tion, coupled with a plain chest radiograph, 24 hours after surgery, early complications identifies most respiratory disease. Pulmonary occur less than 30 days after surgery, inter- function tests and arterial blood gas samples mediate occur within the first year, and late further aid diagnosis. occur after the first postoperative year. Compli- Preoperative therapy involving chest physio- cations occurring immediately perioperatively therapy, smoking restriction, antibiotics, and and within the first 30 days after surgery are bronchodilators can greatly reduce postopera- most often due to technical error or poor tive pulmonary complications. The severity of patient selection. Technical errors include inad- postoperative pulmonary complications can equate anastomotic suturing technique, kinking range from benign minor atelectasis, which is of the graft, and the injudicious choice of a usually self-limiting, to a fulminant acute respi- poor-quality, small-diameter graft. Poor quali- ratory failure that carries a very high mortality. ties of either inflow or distal run-off are pre- Accordingly, recognition and management of dictors of poor graft longevity. Complications postoperative cardiac and pulmonary complica- ensuing from these errors are usually anasto- tions are essential for the vascular surgeon. motic hemorrhage or a partially or completely

Table 12.2. Time frame for complications of peripheral vascular grafts Immediate Early Intermediate Late Anastomotic bleeding Myointimal hyperplasia Accelerated atherosclerosis Graft infection Graft thrombosis Graft thrombosis Myointimal hyperplasia Atherosclerosis Embolic sequelae Vein graft stenosis Myointimal hyperplasia Graft infection Graft aneurysm formation Vein graft stenosis 135

COMPLICATIONS IN VASCULAR SURGERY thrombosed graft with possible distal embolic injury caused by a bypass procedure or angio- sequelae. plasty of the peripheral arteries can initiate and The wide range of vascular grafts now avail- maintain the process of MIH. The clinical rele- able has revolutionized vascular surgery. How- vance of MIH is pertinent, as the development ever, before a graft is declared competent and of MIH at the outflow anastomosis of a vein durable, long-term follow-up is needed, as graft bypass placed in the arterial system is respon- failure may only become apparent several years sible for most complications leading to revi- after implantation. There are three types of vas- sion surgery. Proliferating smooth muscle cells cular graft: autologous (venous and arterial), migrate to the injury-provoked denuded endo- prosthetic [e.g., Dacron, polytetrafluoroethyl- thelial layer area and forms a hyperplastic ene (PTFE)] and biological prosthetic (e.g., lesion, which is associated with vein graft steno- modified human umbilical vein graft). Once sis and obstruction of the vascular lumen. The functioning in the arterial circuit, each type of pathogenesis of MIH remains under investiga- graft has its inherent drawbacks, leading to tion. However, it has been established that both specific complications. These complications can mechanical and chemical factors may induce be categorized into two groups. Direct compli- this process. Arterial injury is believed to stim- cations involve those where the graft itself fails ulate the production of growth factors, such as (e.g., thrombosis), whereas indirect complica- platelet-derived growth factor (PDGF), which tions are those that relate to a graft that still have been shown to stimulate the proliferation functions (e.g., graft infection, suture line false of arterial smooth muscle cells and the forma- aneurysm). tion of the hyperplastic lesion in the vascular system. A variety of cells, including endothe- lial cells, macrophages, platelets, and smooth Autologous Grafts muscle cells, have been shown to secrete growth factors and cytokines. Blocking the effects of Autologous vein is the conduit of choice for growth factors such as PDGF or fibroblast lower limb arterial reconstruction, as this has growth factor (FGF), by the administration of been repeatedly demonstrated in large retro- antibodies against these growth factors, may spective studies (Bergamini, 1991). limit the development of the hyperplastic lesion Due to its anatomical constancy, the long (or (Neville and Sidawy, 1998). The role of hemody- greater) saphenous vein (GSV) is generally con- namic changes in the vein graft, including sidered to be the vein of choice. However, when altered vessel wall shear stress and increased the GSV has been affected by thrombophlebitis, particle residence time, has also been shown to been removed for previous bypass surgery, or play an important part in MIH growth. Inves- has become dilated and varicosed, the short (or tigations aimed at modifying blood flow dy- lesser) saphenous vein or upper extremity vein namics within vein grafts to diminish MIH (basilic or cephalic) are often used and have development are currently under way. acceptable long-term patency rates. Regard- It has been theoretically proposed that less of the conduit, there remains a significant leaving a vein graft in situ, instead of using the failure rate in autologous vein graft, which is reversed vein graft technique, may lead to fewer associated with considerable morbidity and subsequent complications. Due to the natural mortality. tapering of the vein, an in situ vein graft has a The most common cause of autologous vein better diameter match between the vein and the graft failure in the intermediate and long term native artery at the proximal and distal ends of is the development of myointimal hyperplastic the vein graft. This makes the construction of lesions that lead to vein graft stenosis, subse- both the proximal and distal anastomosis easier quent graft occlusion, and ultimately graft to perform and therefore reduces the probabil- failure. Myointimal hyperplasia (MIH) is the ity of technical errors. A more suitable diameter morphological lesion that underlies vein graft match leads to more favorable blood flow fea- stenosis. It can be described as an abnormal tures with decreased incidence of graft throm- accumulation of cells and extracellular matrix bosis, anastomotic aneurysm, and development in the intima of the vessel wall. The mechanical of MIH. Also as the blood supply to the vein 136

VASCULAR SURGERY graft through the vasa vasorum is still partially Diagnosis intact, the vein graft remains less hypoxic. Conversely, as the need to use a valvulotome The diagnosis of an occluded infrainguinal graft to obliterate the valves is essential, damage to is made clinically, but can be confirmed by the vessel wall may ensue, possibly leading duplex ultrasound. Presentation ranges from to increased risk of early graft thrombosis. a sudden onset of a reduction in pain-free However, biological studies of the integrity of walking distance to acute limb ischemia. From the vein wall in in situ and reversed vein grafts the history, the time of onset of occlusion can be have failed to show significant differences. It is ascertained, and the time frame between ori- important to note that several studies have ginal surgery and occlusion can aid in the found no significant difference in complication etiology (Table 12.2). rates resulting from either technique. Management Prosthetic Grafts If a thrombosed graft presents within hours or days of the occlusion, the limb is usually viable Once incorporated into the circulation, the and the aim is to restore graft patency. In the luminal surface of a prosthetic graft becomes absence of contraindications, thrombolysis is lined with fibrinogen, followed by fibrin and indicated. Hemorrhage at the site of catheter red and white blood cells. This layer is known thrombolysis insertion occurs in 10% to 30% of as a pseudointima. Whereas prosthetic grafts cases and is the most common complication. perform well in a high-flow environment (e.g., The most catastrophic complication of throm- in aortic reconstruction), their performance in bolysis is intracranial hemorrhage that is often the infrageniculate position is poor compared fatal, in particular in elderly patients with a with that of autologous vein. The main problem history of stroke. Bleeding into other organs is leading to poor long-term graft patency is the also commonly recognized. Due to the high increased thrombogenicity of prosthetic distal complication rate during thrombolysis, if an bypass grafts. Some have advocated the case for occluded lesion does not render the patient crit- primary amputation being first-line treatment ically ischemic, it can be argued that thrombol- when autologous vein is unavailable for a distal ysis is not justified. bypass. If after successful thrombolysis an underlying Originally, Dacron grafts were used as the lesion is identified, the patient should be material of choice for distal bypass. However, heparinized and the lesion corrected. Jump due to very poor patency rates, PTFE took over grafting or patch angioplasty is an appropriate as the prosthetic conduit of choice.As well as the procedure. When a myointimal hyperplastic complications resulting from increased throm- lesion postthrombolysis is found, transluminal bogenicity of prosthetic grafts, graft infection balloon angioplasty, patch angioplasty, or inter- has dire consequences, described later in this position grafting can be used, as well as jump chapter. grafting. Autologous vein is preferable for sec- ondary reconstructions. An emergency revascularization is the man- Lower Limb Graft Occlusion agement of a graft occlusion associated with a threatened limb. Loss of neurological function As the majority of vascular grafts in the lower coupled with a tender and tense calf is an indi- limb are performed for critical limb ischemia, cation for urgent surgery. The procedure differs graft occlusion often reverts the limb back to depending on the type of graft. The aim of treat- its original critical state or worse. Moreover, ment of a thrombosed vein graft threatening the ischemia may be compounded due to a reduc- limb is restoration of graft flow with correction tion in collateral flow caused by division of of any underlying abnormality. The distal anas- vessels during surgery, by physiological reduc- tomosis should be opened and the graft and tion of collateral flow as a result of a successful distal vessels cleared of thrombus. On-table graft, or by thrombosis extending distally into angiography should be performed once flow has the run-off vessels. been restored. Then any abnormality can surgi- 137

COMPLICATIONS IN VASCULAR SURGERY cally be corrected as previously described. With circumstances, open graft thrombectomy or a prosthetic graft, the aim of an emergency thrombolysis is not possible, and so common procedure is restoration of the original graft practice involves revascularizing the affected function with or without correction of an limb with a femoral artery–to–femoral artery underlying cause. The long-term patency of crossover graft taken from the contralateral salvaged occluded autologous or prosthetic limb.Other extraanatomical reconstructions are infrainguinal grafts is disappointing, and com- also feasible in this situation. plete replacement with a new vein graft, reserv- When the body and limbs of an aortic graft ing graft revision for those patients’ with no are thrombosed, proximal disease advancing better bypass options, has been advocated. Fol- into the graft from the proximal aorta is usually lowing an emergency procedure for lower extre- the cause. This complication can be avoided by mity graft thrombosis, particularly if there has placing the initial graft on the aorta near the been significant preoperative ischemia, the sur- level of the renal arteries. However, once a diag- geon should have an extremely low threshold nosis of total aortic graft occlusion is made, for performing a fasciotomy to prevent muscle most surgeons would undertake an axillob- necrosis. ifemoral graft as an option; redo aortic grafting is major corrective surgery carrying great risk to the patient. Occasionally, a failed aortic graft Complications of will not produce new or acute symptoms because of the development of collateral vessels Aortic Reconstruction in a relatively mobile patient or because immo- bility masks claudication symptoms. If this were Reconstruction of the aorta for atherosclerotic the case, it may be that the patient will present aneurysmal or occlusive disease brings about a many months after the graft has failed, with different spectrum of complication when com- either nonhealing ulcers or rest pain. In either pared with lower-extremity revascularization. case,and to thwart the onset of critical ischemia, The aortic graft used is either Dacron or PTFE, a complete graft replacement is the only option, as there is no autologous conduit large enough as at this stage the graft is usually unsalvageable. to replace the aorta. Due to the high flow through a large-caliber vessel, prosthetic grafts replacing native aorta perform well and have Infected Prosthetic Graft well-documented excellent long-term results. The two most common local complications after One of the most challenging complications in aortic reconstruction are occlusion and graft vascular surgery is a graft infection. Infection infection (see Infected Prosthetic Graft, below). radically changes patient outcomes and is both When an aortic graft or the limb of an aorto- life and limb threatening. Quantifying incidence bifemoral graft occludes, the limb is usually of graft infection is not easy,as many reports are viable. Occlusion of a single limb of an aortic anecdotal and this is compounded by the long graft is most often caused by anastomotic stric- and variable time period between original sur- ture at the femoral anastomosis. If the onset of gery and evidence of graft infection. The the occlusion is in the early phase (within 30 incidence of graft infection, however, is influ- days) postsurgery and the graft can be throm- enced by anatomical site of graft, indications for bolyzed successfully, subsequent patch angio- original intervention, underlying disease, and plasty or distal jump grafting is usually the patients’ host defense. The literature quotes successful. Thrombolysis of retroperitoneal figures that range between 0.7% and 7% for knitted Dacron grafts must be performed with graft infection after aortic surgery. Prosthetic caution because of the risk of extravasation of graft infection is more common after emer- blood into the retroperitoneum. Thrombectomy gency procedures (e.g., ruptured abdominal using ring strippers or adherent clot catheters is aortic aneurysm), or when the graft is anasto- more successful than using ordinary thrombec- mosed to the femoral artery in the groin or sited tomy balloon catheters. It is more common that superficially (e.g., axillofemoral bypass). When the time of graft failure is not known and is and how a graft becomes infected is often likely to be of several weeks’ duration. In these difficult to ascertain, and there are multiple risk 138

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Table 12.3. Risk factors for graft infection collection should be determined whenever pos- Local factors sible. Determining which organisms are in- Prosthetic graft fecting a graft is also imperative to help guide Groin invasion antibiotic choice following graft removal. Once Emergency or lengthy surgery these two factors have been elucidated, the like- Leg ulceration or gangrene lihood of infection must be balanced against the Postoperative wound infection general condition of the patient, the extent of Systemic factors the revision surgery required, and the necessity Diabetes mellitus for immediate intervention. Malnutrition or obesity Chronic renal failure Malignancy Investigations Steroid therapy Having bacteriological cultures done on swabs taken from a discharging sinus may identify the organism involved. Blood cultures may factors for graft infection (Table 12.3). However, also be positive, particularly if blood is drawn there are three modes whereby the graft may from the femoral artery, downstream to a pos- become contaminated: (1) the infection may be sible graft infection. The organisms most com- seeded onto the graft at the time of surgery monly isolated from blood or from wounds (perioperative contamination), (2) subsequent are gram-positive bacteria, Staphylococcus and bacteremia may seed the graft, and (3) direct Streptococcus species. A particularly worrying spread from a nearby source (e.g., skin or duo- phenomenon is the continued rise in the num- denum) may occur. ber of reports of methicillin-resistant Staphylo- coccus aureus (MRSA) isolated from infected Presentation grafts. This organism and gram-negative infec- tions are associated with severe systemic sepsis, Any symptoms and signs of sepsis in a patient and experience in our unit and elsewhere has with a vascular graft should alert the clinician shown these organisms to carry a less favorable to the possibility of a graft infection.With a sub- outcome in terms of limb salvage and mortality cutaneous graft, localized erythema and cellu- than infection with less virulent organisms. litis or a discharging sinus may be clinically Early graft infection is usually associated with visible over the length of the graft, or prosthetic virulent organisms such as S. aureus, Strep- material may be visualized eroding through the tococcus faecalis, Escherichia coli, Klebsiella, skin. With a deep infected graft (e.g., an aortic Pseudomonas aeruginosa,and Proteus or mixed graft), the patient may present with vague pathogens. Late graft infections are usually symptoms and have pyrexia of unknown origin. caused by less virulent bacteria (e.g., Staphylo- An infected aortic prosthesis may form an aor- coccus epidermidis, which is a common skin toduodenal fistula and present with upper gas- commensal). Interestingly, this organism has trointestinal bleeding that may be mistaken for been cultured from grafts that have been peptic ulceration. Less commonly, lower gas- removed for purposes other than infection, trointestinal hemorrhage may be seen from which may signify that only a small proportion aortoenteric fistulas into distal bowel sites. of such contaminated drafts develop graft- Alternatively, signs of septic emboli to the threatening infection. The type of antibiotic extremities may present as a purpuric rash. therapy differs between centers,but it is prudent Other more rare sequelae of a graft infection to discuss an appropriate antibiotic regimen included metastatic mycotic aneurysm forma- with a microbiologist. tion, anastomotic pseudoaneurysm formation, There are a few imaging techniques to eluci- or anastomotic hemorrhage. With all these date the presence and extent of a graft infection. potential sequelae, the clinician must have a Computed tomography (CT) scanning can help high index of suspicion in the presence of a in demonstrating fluid collections around a sus- prosthetic graft. pected infected graft.The presence of gas within Making a definitive diagnosis of graft infec- a perigraft collection is pathognomonic of an tion can be difficult. The presence of a perigraft infection; however, around an aortic graft, gas 139

COMPLICATIONS IN VASCULAR SURGERY may represent resolving thrombus. Computed legs ischemic, and at the time of removal of tomography scanning may also not be able to the infected graft further revascularization is differentiate free gas that is around a graft and required. gas within the bowel that is adhered closely to the graft. Computed tomography–guided aspi- ration of perigraft fluid may be undertaken to Complications Related to aid in diagnosis; however, this carries the risk of introducing infective seedlings into a poten- Disorders of Coagulation tially sterile field. A radioisotope-labeled white blood cell scan The acute thrombosis of an arterial procedure enables localization of occult sites of infection, in the perioperative period is usually seen as labeled granulocytes concentrate around an before the patient exits the operating room and infected focus. Magnetic resonance angiogra- may occur up to 12 hours following surgery. phy of the aorta is believed to be complemen- Dealing with unexplained thrombosis intra- tary to a tagged white cell scan and may increase operatively or in the immediate postoperative the likelihood of appropriately diagnosing a period is one of the greatest uncertainties faced graft infection. Angiography, even though by the vascular surgeon. unable to pinpoint sites of infection, is neces- Hypercoagulability as grounds for an unex- sary for preoperative planning for revision plained vascular thrombosis poses a challeng- surgery. It demonstrates the nature of distal ing clinical problem. Graft failure in the run-off and the state of arteries that may be perioperative period is presumed to result from used in an extraanatomical bypass. Occasionally technical errors in the construction of the it may aid diagnosis in an aortoenteric or aor- anastomosis, problems with the choice of tocaval fistula. Gastrointestinal endoscopy to and quality of vascular conduit, or unsuitable rule out aortoduodenal fistula must be the first- patient selection. Only once these other factors line investigation in a patient presenting with as a cause of failure have been excluded can the hematemesis or melena. diagnosis of abnormal coagulability be formu- lated.When it becomes apparent there is abnor- Management mal coagulation (i.e., heparin is not preventing clotting in the operating field or when there is Graft conservation involves local debridement an immediate thrombosis of a vascular repair), of infected tissues surrounding a superficial the diagnosis can be confirmed only by the graft, followed by a primary wound closure and analysis of a blood clotting profile. It therefore local irrigation with gentamicin antibiotic solu- stands to reason that detection of clotting dis- tion via suitably placed drainage catheters or orders prior to surgery is most often associated impregnated collagen sponge or beads. Another with a favorable surgical outcome. It is with method of graft preservation involves covering experience that a surgeon develops an intuition the debrided area and graft with a vascularized as to which reconstructions are likely to succeed omental or muscle flap. This form of manage- and has some ideas as to the types of complica- ment is strongly proposed for localized groin tions that may occur. Likewise, with experience wound infection in the presence of a patent a surgeon develops a feel for the character- graft and is said to be associated with a low mor- istic presentations of atherosclerotic occlusive tality, high limb salvage rate and an acceptable disease.When abnormal or unexplained throm- incidence of recurrent infection. The decision to bosis is diagnosed (e.g., a thrombosed supra- excise an infected graft should be undertaken renal aorta or upper extremity thrombosis in a carefully, and whenever possible the patient’s patient who is not diabetic and has little evi- condition needs to be optimized prior to the dence of atherosclerotic occlusive disease else- operation. The best-case scenario is when ade- where), the surgeon should investigate clotting quate collateralization has taken place and no disorders as a possible cause. Unusual angio- further revascularization procedure is required graphic findings, particularly young patients once the graft is removed. More commonly, who present with an occlusion in one limb with though, graft removal results in a return to the pristine vasculature in the contralateral limb, preoperative state, often rendering one or both should prompt an investigation into the coagu- 140

VASCULAR SURGERY lation system. The role of screening for poten- hematomas) that require surgical intervention tial thrombophilic states in vascular surgical occur more often in patients with coagu- patients has been studied. Approximately 10% lopathies and in patients who are obese.The risk of all patients scheduled for a variety of vascu- of puncture-site pseudoaneurysm has been lar surgical procedures had test results indicat- shown to increase with increasing catheter size ing a potential hypercoagulable state. The three and when a low puncture site is used. Preven- most common clotting disorders are heparin- tion of puncture-site hematomas and pseudoa- induced platelet aggregation, lupus anticoagu- neurysms can be achieved by using the lants, and protein C deficiency. The incidence of smallest-caliber catheter possible to perform infrainguinal graft occlusion within 30 days was the necessary intervention. Accordingly, there 27% among patients who were in the hyperco- are fewer puncture-site complications with agulable group compared with 1.6% in patients angioplasty procedures when compared with who were not in this group.At present, an estab- stenting, as the catheter needed to place a stent lished screening program does not exist to is of a larger caliber. exclude the wide variety of coagulation disor- Catheter-related complications include the ders present in vascular surgical patients. We formation of arterial dissections, subintimal depend on taking a careful history and clinical injections, and embolization from the catheter. examination to identify those patients who may Fortunately, as the dissections produced are ret- be at a risk of abnormal clotting due to an inher- rograde and are pushed closed by the direction ent thrombophilic status. At this time this is of blood flow, most of these complications are probably the more cost-effective and efficient asymptomatic. However, some acute dissections means to establish a hypercoagulable diagnosis become extensive chronic dissections or cause prior to operation. acute occlusion. Catheter thromboembolism occurs in less than 0.5% of cases. There are myriad systemic complications Complications of associated with angiographic procedures.Exam- ples include vasovagal syncope, cardiac arrest Interventional Vascular and arrhythmias, myocardial infarction, and Radiological Procedures nausea and vomiting. Contrast reactions can be reduced by adequate hydration and by using low As more minimally invasive interventional radi- osmolar contrast in high-risk patients. Rarely ological procedures are being used as first-line radiation injury in the form of a skin burn occurs treatment for occlusive and aneurysmal vascu- when the procedure is lengthy and the patient is lar disease, the incidence of complications is exposed to over 2Gy. rising accordingly. These complications can be divided into three categories: (1) puncture-site related, (2) catheter related, and (3) systemic References complications. About 0.5% of femoral punctures and 1.7% Bergamini TM, Towne JB, Bandyk DF, Seabrook GR and of axillary punctures have been reported to Schmitt DD. (1991) J Vasc Surg 13:137–47; discussion require treatment for a complication. Hema- 148–9. tomas at the puncture site are not usually con- Hannon RJ, Wolfe JH, Mansfield AO. (1996) Br J Surg 83: 654–8. sidered a complication and rarely need surgical Krupski WC, Layug EL, Reilly LM, Rapp JH, Mangano DT. treatment. Large hematomas (e.g., retroperi- (1993) J Vasc Surg 18:609–15; discussion 615–7. toneal, pelvic, and anterior abdominal wall Neville RF, Sidawy AN. (1998) Semin Vasc Surg 11:142–8. 13 Vascular Access David C. Mitchell and C. Keith Ozaki

Vascular access is required to assist in the man- cannulae in the main named veins of the upper agement of patients requiring frequent venous limb, should be avoided. If central venous or arterial cannulation. Its principal role is to catheters are required, they should be sited in provide circulatory access for hemodialysis, al- the jugular and not the subclavian veins to avoid though such techniques are also used to pro- central venous stenosis in the draining veins of vide chemotherapy, intravenous nutrition, and the upper limb. access for plasma exchange. The two techniques used are either implant- able synthetic lines, which may have one or Standards more lumina, or a surgically created fistula between the arterial and venous circulation. The United States has led the way in this area This latter approach may involve joining artery with the publication of specific guidelines and vein together, the so-called autogenous [National Kidney Foundation-Disease Out- arteriovenous (AV) access [arteriovenous fistula comes Quality Initiative (NKF-DOQI) (www. (AVF)], or the insertion of a synthetic bridge kidney.org/professionals/doqi/guidelines)]. graft between artery and vein (nonautogenous These guidelines were a response to the rapid AV access). growth in patient numbers and costs associated with treatment for renal failure. A multidiscipli- nary group of nephrologists, nurses, vascular Principles of Vascular Access and transplant surgeons, and interventional radiologists reviewed the world literature. The The guiding principles of access surgery are to resulting document was approved by all the rep- use AVF in preference to synthetic grafts, which resented national societies prior to adoption. are preferred to in-dwelling central venous The principal recommendations are that the catheters. Access should be sited as far distally majority of patients starting dialysis should do so in the chosen limb as possible. The principle is using a native vessel AVF at the wrist. Grafts to conserve veins to permit proximal revision if require six times as many interventions as AVF to the initial procedure fails. An exception is very achieve the same patency, and their use is dis- old patients, who often have poor distal vessels. couraged.Central catheters have inferior patency Some young patients may have strong wishes to and are discouraged for “permanent” access. avoid visible forearm scars. The nondominant Their principal role should be for emergency or limb should be used wherever possible. temporary access.Since the distribution of these In patients who may require vascular access, standards,placement rates for simple fistulas has venepuncture, or the insertion of intravenous increased 35% in the United States.

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The Europeans have not produced a similar Table 13.1. Preoperative planning for autogenous or document, although it is hoped that a National nonautogenous arteriovenous fistula (AVF) placement Service Framework for renal disease manage- Consider patient age, projected life span, time to ment in the United Kingdom will set standards initiation of dialysis, dominant hand for vascular access within the National Health Elicit history of previous access attempts/subclavian Service. vein cannulations; consider contrast venography to Observational studies have helped to define rule out central venous pathologies Check Allen’s test, upper extremity blood pressures, standards. The Dialysis Outcomes and Practice Æ Patterns Study (DOPPS) was a prospective arterial pulse exam if abnormal then segmental arm pressures, plethysmography Æ if abnormal global study of practice in seven countries then consider ultrasound or angiography involving 309 facilities and over 9500 patients. Venous exam with tourniquet Æ if no clear conduit It showed that there are significant differences then duplex; protect that vein from between varying health cultures in the devel- puncture/trauma oped world. The AVF rates varied from 0% to Ensure patient is optimized for operation (e.g., address 87% in the United States, and 39% to 100% cardiac, metabolic, volume status, nutritional, in Europe. Graft usage in new hemodialysis infectious issues) patients ranged from 2 to 24%. Central venous Consider risks of steal in elderly and diabetic patients lines were particularly common in the United undergoing proximal access construction Kingdom and the United States but rare in Japan and Italy. These differences are not dictated solely by differences between patients, but principally by Brescia-Cimino fistula (Brescia et al., 1966). The clinician preference. This study has clarified end of the vein is joined to the side of the radial what is being done at present to provide access. artery, usually under local anesthesia. By demonstrating widely differing practice, The success of this procedure is dependent on it informs the debate over ideal practice and the quality of the vein and artery and the tech- can guide future trials to answer questions nical skill of the surgeon. Where good vessels about treatment where widely differing views are not clinically evident, duplex ultrasonogra- are held. phy or venography may help to identify the Interpretation of the literature is further com- best sites for access formation. The suggested plicated by differences in reporting of the re- sequence for AVF placement is listed in Table sults of access surgery. A recent study from the 13.2). United States should help to standardize report- Widely varying success rates are quoted, but ing in the future (Sidawy et al., 2002). about 60% of wrist AVFs mature and become useful for dialysis. The AVFs are robust once established, but may take many (typically 6 to Types of Access 12) weeks to mature. Many factors may affect

The principal modes of vascular access are autogenous AVF, synthetic AV bridge grafts Table 13.2. Suggested sequence for AVF placement (nonautogenous AV access), and in-dwelling synthetic central venous catheters. Considera- 1. Autogenous AVF in hand/forearm (nondominant before dominant) tion of patient demographics, anatomical suit- 2. Upper arm autogenous AVF (usually cephalic before ability, and other factors are important in the basilic) preoperative planning for access (Table 13.1). 3. Forearm nonautogenous AVF 4. Upper arm nonautogenous AVF 5. Upper arm or thigh autogenous (using transposed or translocated saphenous/superficial femoral vein) Most clinicians agree that the most durable AVF form of vascular access is the AVF. The prefer- 6. Thigh nonautogenous AVF ential site is between the cephalic vein and 7. Central configurations such as axillary artery to contralateral axillary vein, subclavian artery to the radial artery at the anatomical snuffbox, or subclavian vein the wrist, in the nondominant upper limb, the 143

VASCULAR ACCESS maturation, such as the size of artery and vein, applied to the lower limb in patients with good change in flow, and the presence or absence of arterial circulation, by transposing the long arterial disease (e.g., diabetes). In patients in saphenous vein subcutaneously in the thigh and whom the fistula is failing to become prominent anastomosing it to the distal superficial femoral within a few weeks, duplex ultrasound scanning artery. can examine flow rates and identify problems. Surgeons willing to undertake revision may produce higher success rates. The principal Synthetic Access Grafts reasons for failure are damaged or inadequate (Nonautogenous veins and (more rarely) inadequate arteries. In such cases, alternative forearm veins may be Arteriovenous Access) used. The basilic vein on the ulnar side of the Where veins are inadequate, or dialysis is forearm is often large and may not have been needed urgently (within 2 weeks), AVF may be traumatized by venesection. This can be mobi- inappropriate. In such circumstances, access can lized and swung across the forearm to the radial be rapidly established using synthetic bridge artery, or anastomosed to the adjacent ulnar grafts between suitable arteries and veins. The artery if large enough, although the failure rates most common material for this is polytetra- for this procedure are higher. fluoroethylene (PTFE), which may be cannu- Any vein can be damaged by repeat venesec- lated within a week if required. Dacron is not tion or placement of in-dwelling catheters. Such widely used for access as it is difficult to needle, veins develop areas of fibrosis that cannot dilate but newer composite grafts that are reported when subjected to arterial flows. For this reason, to bleed less after cannulation are available. in those in whom the need for access can be anti- The role of these grafts has yet to be clearly cipated, every effort should be made to avoid established. needling the cephalic vein, the antecubital veins, As veins are often deficient, grafts tend to or the subclavian vein. be placed more proximally in the limb than The radial artery at the wrist is often insuffi- AVFs. They may be placed in either straight cient in the elderly and particularly those with or curved/looped configurations. No data exist diabetes. The artery usually shows evidence of demonstrating that one configuration is signi- arteriosclerosis with calcification. The artery is ficantly better than any other. Grafts should be unable to increase its flow rate in response to appropriately sized with the arterial anastomo- fistula formation. The result is failure of the vein sis not bigger than 6mm to avoid excessive flows to enlarge, or thrombosis. In this situation, it and either vascular steal or high output cardiac may be better to place the fistula more proxi- failure. mally in the limb, typically at the elbow. Pre- Although easier to establish, PTFE grafts are operative evaluation can assist in identifying known to have higher thrombotic and septic suitable patients for distal AVFs (Malovrh, complication rates, and to need more frequent 2002). revision than native AVFs. For this reason, it is The standard procedure at the elbow is an advised that AVFs are preferred. This has never end of cephalic vein to side of brachial artery been formally tested in a prospective random- fistula. This can usually be fashioned through ized trial. In the elderly patient with limited a transverse antecubital incision or two lon- life expectancy, a rapidly established graft may gitudinal incisions under local anesthesia. The provide superior access with sufficient durabil- depth of the basilic vein within the arm com- ity, compared to several unsuccessful attempts plicates its use as a direct fistula. This vein, to establish an AVF. however, may be easily mobilized through a lon- gitudinal incision in the medial arm. The basilic vein is then divided distally, tunneled subcuta- Central Venous Catheters neously, and anastomosed to the brachial artery in the distal arm. The procedure can be per- A well-organized renal failure service should formed using minimally invasive techniques. anticipate the need for access in patients ap- Such transposed fistulas may give good service proaching end-stage disease, and appropriate over many years. This technique may also be access surgery should be planned in advance. 144

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This counsel of perfection is not always realized Failure to Mature as patients may present acutely after a long period of stability. Failure to mature is the most common problem Those requiring emergency access (e.g., im- seen in AVFs. Fistulas demonstrate significant mediate need for dialysis) need the insertion increase in flow within 48 hours and enlarge of a dual-lumen central venous catheter. These thereafter. Most successful AVFs are capable should be left in place for as short a time as pos- of being needled in about 6 to 8 weeks after sible. Definitive access surgery should follow as formation, although longer may be required. a matter of urgency. Detecting those that will fail to mature may be Central catheters become infected easily, and difficult. Ideally, AVFs should be placed well often have to be removed or re-sited. In addi- in advance of the time that they are likely to tion, they stimulate fibrosis in the veins and can be required. This permits time for assessment cause stenosis. For this reason, subclavian lines and revision if the fistula is not developing are to be avoided, as the loss of the subclavian satisfactorily. An alternative approach if time vein prejudices further access in the ipsilateral is pressing is to scan the fistula with ultra- upper limb. Lines should be placed via the sound soon after formation. Flow rates greater jugular route if at all possible. If access is needed than 500mL/min signify that the fistula is likely only for a few days, then in the absence of suit- to develop successfully. Scanning can also be able jugular veins the femoral veins may be used for the early detection of technical used. deficiencies, stenoses, and other problems. In Patients needing more permanent catheters constructions that are failing to mature, some (longer than 3 weeks) should have tunneled groups advocate early liberal use of fistulograms catheters inserted. Placement considerations to aid in diagnosis and therapeutic planning. are the same as for temporary lines. Tunneled Others rely primarily on the diagnostic vascular catheters should be cuffed, as the cuffs reduce laboratory, and reserve fistulography for cases the risk of infection from the site of skin in which duplex scanning is equivocal or entry. unavailable.

Complications of Vascular Stenosis Vein stenosis and aneurysmal dilatation are Vascular Access both seen following development of AVFs. The former may compromise both the quality of Arteriovenous Fistula dialysis and the longevity of the fistula. Some centers advocate routine fistula scanning, but Once the AVF is established, AVF revision this has not yet been shown to be an effective rates are low at about 15% or less per annum. way of monitoring fistulas for complications. Fistulas are robust and withstand multiple Where obvious stenoses exist, or dialysis is cannulations well. inadequate despite an apparently satisfactory fistula, then ultrasound may reveal a stenosis. Technical Failure Stenoses greater than 50% or AVFs with flows below 500mL/min are more likely to fail and The most immediate complication of AV access may need revision. Stenoses within 1 to 2cm of is that the fistula occludes shortly after forma- the anastomosis are most easily dealt with by tion. This may be due to obvious problems such surgical revision. This can be undertaken under as inadequate vessels or to technical imperfec- local anesthesia with an occlusive tourniquet. tions in the procedure. In the former, re-siting The fistula is ligated and divided and reanasto- the fistula is the best course of action. In the mosed to an adjacent portion of artery. More latter situation, revision, often under local remote stenoses may often be dealt with by anesthesia, may salvage a functioning AVF. This angioplasty. If this fails, then short skip grafts of is rarely an emergency and can be managed vein may bypass a stenosis and permit continu- during the next available elective operating ous use of the fistula without the need for tem- session. porary lines. 145

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Vascular Steal and High-Output ous banding. If this happens, the fistula is Cardiac Failure usually lost. High fistula flows can also cause high-output Proximal fistulas tend to have higher flow rates cardiac failure, which is seen more commonly in and may divert blood from the hand. The risk proximal AVFs.In these cases, fistula revision to of vascular steal should be borne in mind in reduce flows is required. The choices include proximal fistula. It is uncommonly seen (about sacrificing the fistula and siting new access, or 1% to 8%), but the neurological effects are irre- attempting a flow reduction procedure. versible if the steal is not quickly corrected (Tordoir et al., 2004). Any suspicion of hand ischemia demands immediate attention, begin- Infection ning with bedside examination. Temporary Infection is rare, but if associated with bac- finger occlusion of the AVF can assist in deter- teremia, abscess, or aneurysm formation, revi- mining whether there is an inflow problem, or sion is usually required. The clinical features whether the arterial flow distal to the arterial are of an area of inflammation in relation to anastomosis has been interrupted. If hand arte- the fistula, sometimes with rapid enlargement. rial perfusion returns to baseline with AVF com- Fever and rigors, particularly on dialysis, may pression, then inflow is inadequate to maintain be seen, but are not a universal feature. Sudden flow to the hand and through the AVF. If the rapid bleeding can occur at infected needling extremity remains ischemic, then there may be sites. Immediate pressure and placement of a a problem with the arterial anastomosis that skin suture will achieve acute control, but occludes outflow, or thromboembolic complica- should be followed by a definitive revision in tions. Segmental arm and finger pressures, fol- most cases. lowed by repeated exam while the access is occluded, confirm the diagnosis. If inflow is inadequate, then improvement of distal pres- Thrombosis sures and symptoms should occur while the AVF Thrombosis is uncommon, but when it occurs or graft is compressed. it can often be retrieved by acute intervention, If steal physiology is demonstrated, then with salvage of the fistula and avoidance of tem- appropriate urgent imaging to screen for occult porary central lines. Overdialysis is an uncom- inflow arterial occlusive disease may be under- mon cause of fistula thrombosis, but should be taken, and lesions addressed. Fistula revision is suspected if no stenosis can be found. Imaging often required. If preservation of the fistula is of the whole fistula and ipsilateral central veins not essential, taking it down and creating a should always follow surgical or radiological new one is probably the procedure of choice. declotting. Dilatation of fistula or central vein The alternatives are banding to reduce flow, or stenosis may be required to restore normal bypass from the artery at least 6cm above the function. When the stenosis is in close proxim- anastomosis to an artery distally and then liga- ity to the anastomosis, then surgical revision to tion of the artery immediately beyond the anas- an adjacent proximal arterial segment is often tomosis. This last procedure is known as the the best procedure. distal revascularization-interval ligation (DRIL) The complications associated with trans- procedure. It is gaining in popularity as it takes posed fistulas are the same as those seen with flow to the distal arterial tree from above the other native AVFs.They tend to have high flows, fistula and prevents steal due to reversed flow in so cardiac failure and steal are more common in the artery distal to the anastomosis. these fistulas. Banding is a complex procedure, necessitat- ing intraoperative flow measurement. Flows Arteriovenous Access may fluctuate during the procedure, but ideally the banding should produce a flow between 800 Grafts (Nonautogenous mL and 1.5L per minute. Success rates for this Arteriovenous Access) procedure are low, and it is not recommended if an alternative is available. Postoperative throm- Arteriovenous grafts can usually be established bosis is common and may be due to overvigor- easily, with a high technical success rate. How- 146

VASCULAR SURGERY ever, complications are common, and the fre- excision with skip grafting through uninvolved quent need for intervention should prompt the tissue may keep the graft functioning. The site surgeon and dialysis team to undertake regular of infection should be left open to drain freely, surveillance. and the patient treated with parenteral anti- biotics until the inflammation has completely subsided. Thrombosis Thrombosis is usually the consequence of Vascular Steal intimal hyperplasia at the venous end of the graft. This can be recognized by regular intra- This is most commonly seen in arm grafts in dialysis monitoring of flow or pressure. It has older or diabetic patients. Rates vary from been shown that monitoring of flow or pressure between 1% to 19%. The approach is the same can detect developing graft stenosis. Timely as steal in an autogenous AVF, with nonautoge- intervention can prolong graft survival. One nous graft ligation or DRIL being the potential approach is to use balloon angioplasty where management approaches. possible, keeping surgical revision to a minimum. Where thrombosis occurs, prompt declotting undertaken by either an endovascu- Aneurysm Formation lar or open approach can retrieve graft function. With repeated cannulation over small areas of It is important to identify and correct the cause a graft, there is a tendency for “aneurysm” for- of the thrombosis or further thrombosis is mation (actually a pseudoaneurysm). This is a likely. There is no clear evidence whether open result of longitudinal splitting of the graft. It or endovascular approaches are superior in this is not a problem if there is good skin coverage, situation, and each approach has its proponents. but if enlarging rapidly or if inflamed, then As grafts require relatively frequent interven- early revision should be undertaken to prevent tions, many advocate using minimally invasive rupture and bleeding. The technique is similar techniques first and reserving open surgery to that used for infection, with the exception for those in whom the vascular interventionist that excision of the aneurysmal portion of the fails. graft is not always necessary in the absence of infection. Infection Like any foreign material, infection is an Central Venous Catheters ever-present hazard, especially as needles are Infection frequently introduced into the graft. Septic episodes in dialysis patients are most likely to Infection is the main problem from central originate from the graft. Great care must be venous (CV) catheters, and rigorous aseptic taken to use aseptic techniques when cannulat- technique is required to manage dialysis. Newer, ing grafts, as once organisms are seeded into totally implantable catheters that are accessed a graft the only way to get rid of them is to through the skin may reduce the risk of sepsis. replace the graft. Eradication of nasal car- The teaching of correct hand and skin prepara- riage of Staphylococcus aureus by use of topical tion prior to needling remains an important mupirocin has been shown to reduce the rate of part of the management of patients with CV graft sepsis. catheters. Grafts are often placed in European prac- Once infected, lines need to be changed. tice as a dialysis access of last resort, and there Ideally, the old line should be removed and the may be limited alternative sites if an infected patient treated until he or she is well before graft is removed. Clearly if there is inflamma- inserting a new line. This is not always possible. tion along the length of the graft, then removal Rotating the line to a new site is to be preferred is the only option. Where localized sepsis exists, in such situations, but if the situation is desper- or a small area of the graft is exposed, local ate, removing the old line and reinserting in the 147

VASCULAR ACCESS same location while treating with antibiotics three separate determinations performed at may be successful. a single treatment should be considered the access flow. If access flow is less than 600mL/ min, the patient should be referred for fistulo- Fibrinous Encasement and Clotting gram. Access flow less than 1000mL/min that The tips of catheters become covered with a has decreased by more than 25% over 4 months “biofilm” of fibrin that may contain bacteria. should be referred for fistulogram.” Even if sterile, this film can build up until a large This is a counsel of perfection and some tube of fibrin encases the catheter tip. This can centers would advocate duplex ultrasound prior to fistulography. Where there is evidence of a interfere with blood flow and obstruct dialysis. > If the line is not infected, removal and replace- stenosis of 50%, there is a significant sub- ment may still be necessary to reestablish dial- sequent thrombosis rate. Such fistula should ysis. Passing guidewires down the catheter is undergo endovascular or surgical revision as not usually successful, but snaring the catheter appropriate. Juxta-anastomotic stenoses are tip radiologically and stripping the fibrin cuff often best dealt with by surgery, with endovas- can clear the offending plug. This technique can cular dilatation being reserved for those in the significantly prolong the life of central lines. body of the access. Thrombosis is a common problem, especially if the line is not used frequently. Lines should be flushed with the correct volume of heparin Desperate Access (1000U/mL) after each use to remove blood from the lumen and prevent thrombosis. Extra Dialysis is becoming more successful in pro- care must be paid to this in children, as it is easy longing the lives of patients in renal failure. to give excessive volumes of heparin and induce Unfortunately, this improvement in survival is systemic anticoagulation and bleeding. not being matched by increases in transplanta- tion. As a result, many more people are depend- ent on long-term dialysis. As successive access procedures fail, the establishment of secure vas- The Avoidance of cular access becomes increasingly difficult. Complications: Surgeons and interventionists have become ingenious at inserting grafts or lines into Access Surveillance various veins, sometimes accidentally. Grafts can be placed in necklace fashion between one Concerns about the frequent need for access axilla and the contralateral one. Arteries can revision have stimulated inquiry into tech- be divided and interposition grafts inserted. niques for the early detection of access com- The superficial femoral vein has been utilized plications before symptoms develop. Most as a hemodialysis access conduit. Lines may techniques concentrate on intradialytic moni- be inserted directly into the inferior vena cava toring of flow, pressure, dialysis efficacy, or a (IVC) through the back. Such procedures should combination of these. The advantage of intradi- be reserved for those in whom no alternative alytic monitoring is that it minimizes the need can be found after an extensive search using for extra hospital resources for these ill patients. ultrasound, venography, and magnetic reso- Each technique has its proponents,and the tech- nance angiography if necessary. It should be niques mentioned are not mutually exclusive. made clear to patients undergoing these proce- The DOQI guidelines state, “Access flow dures that the risks involved in establishing such measured by ultrasound dilution, conductance access are high, and the consequence of failure dilution, thermal dilution, Doppler or other may be fatal. technique should be performed monthly. The Although successful arterial access can be assessment of flow should be performed during obtained for numerous patients with reason- the first 1.5 hours of the treatment to eliminate able durability, numerous controversies remain error caused by decreases in cardiac output (Table 13.3). These controversies will be related to ultrafiltration. The mean value of resolved with further clinical trials. 148

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Table 13.3. Contemporary controversies References Role of endovascular vs. open management of the failing and failed autogenous AVF and Brescia MJ, Cimino JE, Appell K, Hurwich BJ, Scribner BH. nonautogenous AVF (1966) J Am Soc Nephrol 10:193–9. Construction of upper arm autogenous AVF prior to Malovrh M. (2002) Am J Kidney Dis 39:1218–25. utilization of forearm nonautogenous AVF Sidawy AN, Gray R, Besarab A, et al. (2002) J Vasc Surg Role of invasive imaging (routine arteriograms and 35:603–10. venograms) prior to vascular access constructions Tordoir JH, Dammers R, van der Sande FM. (2004) Eur J Vasc Adjuvant therapies to improve vascular access patency Endovasc Surg 27:1–5. (anticoagulants, antiplatelet therapies, etc.) Unknown value of new nonautogenous AVF conduits (modified Dacron, homografts, etc.) Role of duplex surveillance in identifying the failing graft 14 Outcome Measures in Vascular Surgery Christopher J. Kwolek and Alun H. Davies

Background The IOM report also led to the establishment of the Quality Interagency Coordination Task Initial efforts within the health care reform Force (QuIC), which was charged with coordi- movement in the United States largely focused nating the quality improvement activities in U.S. on reducing cost. This became the preeminent federal health care programs. These groups issue as health care expenditures continued to have been responsible for the establishment of increase on an annual basis, reaching 14% of standardized guidelines and protocols based on gross domestic product in 1994. Although some clinical trials, which may decrease variability in of these expenses can be attributed to improve- the patient care processes while improving care ments in diagnostic and therapeutic regimens, and reducing costs. The vast majority of the particularly in those areas highly influenced errors identified in these studies were systems by new technologies, concern has also been related and not attributable to negligence or expressed about the quality of the product being misconduct. In fact, up to 75% of the medical provided to patients. errors and 54% of the surgical errors were found The publication of the Institute of Medicine’s to be preventable. (IOM) Committee on Quality of Care report,“To The U.S.Veterans Administration (VA) hospi- Err Is Human: Building a Safer Health System,” tal system had already begun to look at these shifted the focus of attention from cost alone quality and outcomes issues through the estab- to medical errors within the U.S. health care lishment of the National VA Surgical Quality system and the costs associated with these Improvement Program (NSQIP),which has been errors. This has led to an erosion of patient trust responsible for assessing specific surgical out- in the medical care system.It has been estimated comes throughout the U.S. VA hospital system, that medical errors are responsible for between while using risk adjusted data to assess surgical 44,000 and 98,000 deaths annually, becoming morbidity and mortality and providing specific the eighth leading cause of death in the U.S., institutional feedback (Khuri et al., 1998). In ahead of other causes such as breast cancer fact, this program was so successful that in the and motor vehicle accidents. Over 7000 of these late 1990s it was expanded to include three large deaths were attributed to medication errors academic medical centers at the University alone, with the total cost to society of these of Kentucky, the University of Michigan, and errors estimated to be $11637.6 billion a year. Emory University in Atlanta. Currently this Much of the initial research describing the program is being expanded to include multiple problem of medical errors was performed in the academic medical institutions across the U.S. 1990s and supported by the Agency for Health- In addition, large companies, which are pur- care Research and Quality (AHRQ). chasers of health care for their employees, have

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Table 14.1. Current recommendations of the Leap Frog Group for a health care system to identify the reasons Computerized physician order entry: mandated use to and processes that allow one facility to have minimize medication errors excellent outcomes so that these can be utilized Intensive care unit (ICU) physician staffing: use of by other facilities to achieve the same excellent critical care certified physicians to provide exclusive results. This concept was used by the Northern care of ICU patients New England Cardiovascular Disease Study Evidence-based hospital referral: preferential referral of Group to improve the outcomes of patients patients undergoing five high-risk surgical undergoing coronary artery bypass grafting in procedures to “high volume centers” northern New England (O’Connor et al., 1996). Procedure Annual volume requirement Coronary artery bypass grafting 500/year Outcomes Measures Percutaneous coronary angioplasty 400/year Carotid endarterectomy 100/year It has become important that we evaluate the Abdominal aortic aneurysm repair 30/year relative value of different treatment regimens to Esophagectomy 6/year include individual and societal costs and poten- tial risks and benefits. Individual patient per- spectives on quality have also become an important part of the evaluation process. begun to take an interest in improving the There are several reasons for physicians to quality and potentially decreasing the cost of participate in this process. Ideally, our partici- health care as demonstrated by the activities of pation should lead to an overall improvement in the Leap Frog Group (www.leapfroggroup.org). the quality of care that we deliver. In addition, The stated purpose of this group of Fortune 500 participation in these programs will soon be companies is to mobilize employer purchasing necessary to qualify for reimbursement from power to trigger breakthroughs in the safety many insurers and purchasers of health care and overall value of health care to American such as the U.S. government and the Leap Frog consumers. Using the results of these and other Group. Finally, as physicians we have a societal studies aimed at evaluating medical outcomes, responsibility to maximize the good and mini- the Leap Frog Group has already identified three mize adverse outcomes in health care, while areas to decrease errors and improve the quality best utilizing the limited resources that exist. in U.S.-based health care systems. Health care If physicians choose not to participate in this providers who adopt these recommendations process, then others will make these difficult will be rewarded with preferential use and decisions for us. other incentives by this group of health care These changes have led to the development purchasers. The current recommendations are of “extended outcome assessment” rather than listed in Table 14.1. It is estimated that imple- just the traditional physician-oriented out- mentation of this program would save 60,000 comes measures that we are used to. The con- lives with a monetary savings of $3.8 billion a cept of a value compass has been proposed year. to describe the interplay between traditional Although these recommendations are sup- medical outcomes, patient satisfaction, func- ported by reviews of outcome studies in the tional assessment, and cost/utility outcomes current medical literature, certain limitations (McDaniel et al., 2000). do exist. For example, volume-based outcome studies demonstrate that on average, high- Clinical Status volume centers have better patient outcomes for certain high-risk procedures such as repair of The most traditional group of medical out- abdominal aortic aneurysm (AAA) or carotid comes measures utilized by vascular surgeons endarterectomy (CEA). However, some high- usually describes clinical status. These measures volume centers may have average or poor out- are physician oriented and include measure- comes, whereas some smaller centers with low ments of morbidity and mortality,graft patency, volumes may have excellent outcomes. It may be limb salvage, complications, and laboratory more important to measure the clinical process testing such as the ankle–brachial index (ABI) 151

OUTCOME MEASURES IN VASCULAR SURGERY and duplex ultrasound results. Many of these health assessment instruments are designed to outcomes are important measures of technical quantify how illnesses and treatments affect success and are easily evaluable by statistical different aspects of patient functioning in every- methods such as life table analysis. However, day life. This will allow physicians to evaluate even the long-term results within this category not only the presence or absence of a leg or the such as patient survival after aneurysm repair, patency of a graft, but how patients are func- stroke-free survival after carotid endarterec- tioning after a specific intervention.These meas- tomy, or amputation-free survival after lower ures are also helpful when evaluating patients’ extremity bypass grafting do not necessarily expectations before and after specific interven- correlate with patients’ overall well-being, day- tions.A list of commonly used measures of func- to-day functioning, or their perceived quality of tional status is included in Table 14.2. There life. Physicians are also comfortable with these are two types of assessment tools. The specific outcomes since the Society for Vascular Surgery instrument focuses on a specific disease or client (SVS) and the International Society for Cardio- group, and changes in this are more likely to vascular Surgery (ISCVS) have published guide- detect subtle changes in quality of life, whereas lines for measuring these types of outcomes for generic tools give a broader summary of health- commonly performed arterial and venous vas- related quality of life, hence enabling compar- cular procedures. isons with patients suffering from other disease processes (Table 14.3). Patient Satisfaction The most widely used generic functional health assessment instrument in the United Patient-oriented outcomes tend to be less fre- States is the Medical Outcomes Short Form 36 quently measured and not as well defined. None (SF-36). This survey evaluates patient function of these outcomes are included in the SVS- in physical and social roles, limitations due to ISCVS reporting standards. Patient satisfaction health or emotional problems, patient percep- with the health care process is one area being tions of general health, mental health, bodily more closely evaluated. Although customer sat- pain, and vitality. In addition, a question con- isfaction surveys have long been used in the cerning change in health status compared to 1 world of business, they are now being applied year previously is included in the survey. This to the area of health care. Two areas being fre- survey combines aspects of a Quality of Well- quently evaluated include patient satisfaction Being Scale and a Functional Status Question- with the physician–patient relationship and sat- naire. The reason that this survey has become so isfaction with the health care delivery process. useful is that large numbers of patients have This may include such issues as timeliness and been evaluated using this instrument, thus access to care, provider and staff communica- allowing researchers to compare results to the tion, the physical environment where care is general population or a patient subgroup with delivered, and courtesy and respect shown to specific characteristics. These results may be the patient. Managed care plans in the U.S. are now required to assess themselves using stan- dardized patient satisfaction surveys such as the Table 14.2. Examples of measures of functional status Health Plan Employer Data and Information Set General status: quality of life (HEDIS), which was developed by the National SF-36 Committee for Quality Assurance (NCQA). Euro-QOL Many employers and purchasers of health care Nottingham Health Profile are now utilizing this information when decid- Functional Status Questionnaire ing on which health care providers to include in Quality of Well-Being Scale their panel of providers. Sickness Impact Profile Disease/symptom specific: quality of life Walking Impairment Questionnaire: for patients Functional Status with lower extremity arterial occlusive disease Functional status is another of the patient- Charing Cross Claudication Questionnaire Charing Cross Venous Ulcer Questionnaire oriented outcomes that is being more com- VascQuol monly described in the vascular literature.These 152

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Table 14.3. Advantages and disadvantages of quality of life instruments Instrument Advantages Disadvantages Generic Single instrument May not focus adequately on main problem Detects different aspects of health May lack responsiveness Enables comparison between different conditions Does not take account of values attributed to levels Can be used in cost analysis of quality of life Specific Focus on primary are of interest Not comprehensive More relevant to clinicians and clinical condition May miss side effects May be more responsive Cannot compare across conditions

helpful in predicting long-term functional out- lowest outcomes were found in patients who comes in patients. Thus patients scoring above underwent amputation after failed attempts a certain level in the area of bodily pain may at secondary revascularization. These results have a decreased chance of successfully return- confirm clinical findings that are often well ing to work, and patients with decreased overall known in clinical practice but that are not shown scores in the areas of physical and social func- by primary or secondary patency rates or limb tion and health may have an increased 5-year salvage. mortality. However, the abbreviated form of the Additional concerns have been expressed SF-36, the SF-12, is growing in popularity. about the potential for patient bias with self- In addition to general evaluations of func- reporting of health status. However, patient tional status, disease-specific instruments have reports of functional health status appear to also been developed. One of the most widely have good face value validity. Thus patients who used surveys for the evaluation of patients with suffer from severe strokes report worse func- lower extremity arterial occlusive disease is tioning in the areas of physical and general the Walking Impairment Questionnaire (WIQ); health than patients with mild strokes.Similarly, however, there are newer and more specific patients with venous ulcers report impaired questionnaires becoming available (Chong et social interaction, domestic activity, and emo- al., 2002). Because peripheral vascular disease tional status with improved functioning after has a detrimental effect on quality of life even healing of their venous ulcers (Smith et al., in patients without the most severe forms of 2000).Also, the benefits of varicose vein surgery limb-threatening ischemia, these instruments can be justified in terms of improvements in may be very useful in evaluating the benefit to quality of life scores. patients undergoing treatment for claudication. These surveys may be even more important for evaluating patients undergoing prophylactic Cost/Utility interventions for the management of asympto- matic disease. Cost outcomes are another important area of Some authors have recommended that a com- recent interest. Increasing pressures are being bination of two different surveys such as the exerted by the government and insurers to SF-36 and the EuroQol be used to evaluate the optimize the quality of the health care while quality of life outcomes in patients with and minimizing expenditures. True costs to the indi- without ischemic complications who are under- vidual and society must be calculated both for going infrainguinal bypass grafting (Tangelder the acute illness and over the long term. et al., 1999). Tangelder et al.found that the com- Practice guidelines can often be established bination of the SF-36 and the EuroQol provided based on the results from existing controlled useful information concerning the patients’ clinical trials. These guidelines can then be used quality of life after lower extremity bypass graft- on a regional or national basis to evaluate physi- ing. Interestingly, patients’ functional outcomes cians and health care organizations. Using the were similar for those with asymptomatic same processes of continuous quality improve- graft occlusions and patent grafts, although the ment (CQI) found in major industrial manufac- 153

OUTCOME MEASURES IN VASCULAR SURGERY turing plants, these guidelines should reduce QALY was defined as not cost-effective. Inter- variation in the processes of care, thus improv- estingly, one could extend the evaluation even ing quality while decreasing cost. These guide- further to include the individual’s risk aversion lines are designed to evaluate processes, with and risk taking behavior when defining the the ultimate philosophy of continuously impro- cost-effectiveness for that person. This is es- ving the process to ensure the best possible sentially what occurs every time we obtain outcome. informed consent from a person who is about to This process is in contradistinction to the undergo a high-risk procedure. more traditional concept of quality analysis (QA), where minimum standards or thresholds are set to ensure a good outcome and only out- liers are evaluated rigorously. The pitfall of this Conclusion approach is that it encourages organizations to The reasons for physicians to utilize extended be just “good enough” and meet the minimum outcomes assessment include the following: standards set rather than aim for being the best (1) to achieve a better understanding of the possible. In addition, it singles out only those effectiveness of our interventions; (2) to pro- groups or individuals doing a poor job rather vide health care consumers, both patients and than rewarding groups that are doing a good job insurers, with information that will allow them and trying to reproduce those results in other to make better informed decisions; and (3) to areas. develop public health standards that will allow The value that patients and society place us provide the most cost-effective care on certain outcomes and levels of functioning (McDaniel et al., 2000). can also play a role in evaluating the cost- In addition, the Accreditation Council for effectiveness of certain procedures. The cost- Graduate Medical Education (ACGME) in the effectiveness of a certain intervention can be United States has mandated that all residency expressed as the net benefit to a population by training programs evaluate as part of their core using statistical probabilities of certain out- competency requirements six areas, all of which comes occurring along with specific costs asso- involve some component involving outcomes ciated with various outcomes as documented measures: (1) practice-based learning, (2) from the medical literature. One example of systems-based practice, (3) medical knowledge, this is the use of the Markov decision model to (4) patient care, (5) interpersonal and com- evaluate the cost-effectiveness of performing munication skills, and (6) professionalism carotid endarterectomy in asymptomatic pa- (www.acgme.org/outcomes). tients with >60% stenosis (Cronenwett et al., Finally, the incorporation of outcomes meas- 1997). The measurement units in this study are ures are now being studied by the task force on in quality-adjusted life years (QALYs) defined as competence of the American Board of Medical the fraction of a year in perfect health that the Specialties to be used in the process of recer- patient believes to be equivalent in value to a tification.In fact,recommendations have already year in the health state in question. been published stating that outcomes measures In this study, Cronenwett et al. demonstrated should be included as part of the requirement that from a societal standpoint, carotid endar- for recertification in vascular surgery by the terectomy appeared to be cost-effective for the American Board of Surgery (Hertzer, 2001). young asymptomatic patient with standard risk factors in the hands of a surgeon with a 2.3% 30-day perioperative stroke and death rate. However, the procedure was not found to be References cost-effective for patients older than 79 years of age, those with a high perioperative stroke risk, Chong PF, Garratt AM, Golledge J, Greenhalgh RM, Davies or those with a particularly low stroke risk with AH. (2002) J Vasc Surg 36:764–71; discussion 863–4. medical management. In this study it is impor- Cronenwett JL, Birkmeyer JD, Nackman GB, et al. (1997) J Vasc Surg 25:298–309; discussion 310–1. tant to note that cost-effectiveness is compared Hertzer NR. (2001) J Vasc Surg 34:371–3. to cost/QALY for other medical interventions, Khuri SF, Daley J, Henderson W, et al. (1998) Ann Surg and that a cost of over $100,000/additional 228:491–507. 154

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McDaniel MD, Nehler MR, Santilli SM, et al. (2000) J Vasc Smith JJ, Guest MG, Greenhalgh RM, Davies AH. (2000) Surg 32:1239–50. J Vasc Surg 31:642–9. O’Connor GT, Plume SK, Olmstead EM, et al. (1996) JAMA Tangelder MJ, McDonnel J, Van Busschbach JJ, et al. (1999) 275:841–6. J Vasc Surg 29:913–9. 15 Carotid Artery Disease A. Ross Naylor, Peter H. Lin, and Elliot L. Chaikof

Epidemiology age of 55 years. For those aged 0 to 44 years, the annual incidence of stroke is 0.09 in 1000, Stroke increasing to 2.9 in 1000 for those aged 55 to 64 and 14.3 in 1000 in those aged 75 to 84. The A stroke is defined as a focal (occasionally largest incidence is observed in populations global) loss of cerebral function lasting for more aged >85 years, where the incidence is almost than 24 hours, and which after investigation is 20 in 1000. In both the United States and the found to have a vascular cause. Stroke is respon- United Kingdom,the incidence of stroke is twice sible for 4.5 million deaths worldwide, with the as high in blacks as in white. This ethnic dif- majority occurring in nonindustrialized coun- ference is thought to be due to the increased tries. In the United States, stroke is the third incidence in blacks of risk factors such as hyper- most common cause of death, with approxi- tension, diabetes, smoking, obesity, and sickle mately 160,000 Americans dying from the cell disease. disease each year. Stroke management con- sumes $45 billion annually, including indirect costs and is responsible for more than one Transient Ischemic Attack million hospital discharges per annum. The demographics are remarkably similar in A transient ischemic attack (TIA) has the same the United Kingdom, where stroke is also the definition as stroke but it lasts for less than third leading cause of death (12% of deaths 24 hours. The 24-hour threshold is somewhat overall) and 58,000 Britons die each year. Five arbitrary, as up to 28% of TIA patients have an percent of the National Health Service budget is infarct on computed tomography (CT) scan, of used in stroke care (excluding indirect costs), which 36% are bilateral. In the U.S., the preva- and stroke patients occupy 20% of acute hospi- lence of TIA in men aged 65 to 69 years is 2.7%, tal beds and 25% of rehabilitation beds. increasing to 3.6% for men aged 75 to 79 years. The incidence of stroke is 2 in 1000 per The respective prevalence figures for women are annum, but significantly increases with con- 1.6% and 4.1%. In the U.K., the overall incidence current risk factors of age, sex, and ethnic of TIA is 0.4 in 1000, but this varies with age. background. Overall, the 20-year risk for a 45- The incidence is 0.25 in 1000 for those aged 45 year-old man is 3%, but this increases to 25% for to 54 years, increasing to 1.61 in 1000 in the 65- a 40-year risk (Bonita, 1992). The annual inci- to 74-year age group and 2.57 in 1000 in those dence of stroke doubles for each decade over the aged 75 to 84 years.

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Etiology of Ischemic Stroke and the extent of the thrombosis. Once the internal carotid artery (ICA) has thrombosed, Approximately 80% of strokes are ischemic and the column of thrombus usually propagates 20% hemorrhagic. This section deals primarily distally to the ophthalmic artery. However, the with the etiology of ischemic carotid territory thrombus may occasionally extend beyond the stroke. ophthalmic artery and propagate into the circle of Willis. A very small proportion of strokes (<4%) are Thromboembolism secondary to isolated cerebral hypoperfusion. Patients susceptible to this type of stroke include Approximately 50% of all ischemic carotid ter- those with critical ICA stenoses, poor collateral- ritory strokes follow a carotid thrombosis or ization via the circle of Willis, and a secondary embolism from a carotid stenosis (Fig. 15.1) trigger such as hypotension following an acute into territories supplied by either the middle cardiac event. cerebral artery (MCA) or the anterior cerebral Rarely, carotid thromboembolism may cause artery (ACA). The sequelae of carotid thrombo- posterior (vertebrobasilar) territory strokes. sis depend on a number of factors, including the This arises because, embryologically, the ICA status of the circle of Willis (potential for col- provides the blood supply to the developing lateralization), the chronicity of the thrombosis, posterior cerebral hemispheres and brainstem via the posterior communicating and posterior cerebral arteries. In a very small proportion of the population, this anatomical arrangement persists into adult life.

Intracranial Small-Vessel Disease Occlusion of the penetrating end arteries (lenticulostriate, thalamoperforate) in the deep structures of the brain causes discrete wedge-shaped infarctions of brain tissue. These ischemic lesions, termed lacunar infarcts, are responsible for up to 25% of ischemic carotid territory strokes. Conditions predisposing toward lacunar infarction include hypertension and diabetes. There is still considerable debate as to whether embolization from a carotid stenosis can cause lacunar infarction.

Cardiac Embolism Cardiac embolism accounts for 15% of ische- mic carotid territory strokes. The emboli con- sist of fibrin, cholesterol, calcified debris, and atheroma depending on the underlying pathol- ogy. Sources include valvular heart disease, prosthetic valves, atrial myxoma, ventricular aneurysm thrombus, cardiomyopathy, and in- Figure 15.1. Selective intraarterial digital subtraction angio- fective endocarditis. However, the commonest gram of left carotid bifurcation showing diffuse disease of the causes are atrial fibrillation and embolization upper third of the common carotid artery,a stenosis at the origin of mural thrombus overlying a dyskinetic seg- of the external carotid artery, and a complex severe stenosis at ment of myocardium following a myocardial the origin of the internal carotid artery with deep ulceration. infarction (MI). 157

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Hematological Causes A variety of pathologies predisposing toward a hypercoagulable state are responsible for about 5% of ischemic strokes. These include poly- cythemia, sickle cell disease, leukemia, throm- bocythemia, malignancies, functional protein S deficiency, lupus anticoagulant (antiphospho- lipid antibody syndrome), antithrombin III deficiency, and the paraproteinemias.

Miscellaneous Causes Figure 15.2. Atheromatous plaque excised at carotid endar- Miscellaneous causes account for the remain- terectomy. Note the deep area of ulceration in the plaque ing 5% of ischemic carotid territory strokes. surface. These include migraine, oral contraceptive use, trauma, dissection, giant cell arteritis, Takayasu arteritis, systemic lupus erythematosus (SLE), velocity and high shear stress in the flow model) polyarteritis nodosa, amyloid , co- were relatively free of plaque formation. caine abuse, fibromuscular dysplasia, and radi- The smooth muscle cell has an important ation arteritis. role in the initial stages of plaque develop- ment. Smooth muscle cells migrate through the intima, proliferate within the media, and promote accumulation of cholesterol and other Pathology of Carotid lipid molecules within the evolving lesion. Artery Disease Thereafter, the macrophage becomes a source of growth factor production that stimulates further Atherosclerosis smooth muscle cell proliferation and extracellu- lar matrix production. Smooth muscle cells and Atherosclerosis is the commonest pathology macrophages initiate a secondary inflammatory affecting the carotid artery. The typical plaque cell reaction and are capable of ingesting lipid encountered at carotid endarterectomy (Fig. and of being transformed into vacuolated foam 15.2) is the culmination of a sequence of patho- cells that are characteristic of atherosclerotic physiological processes starting with endothe- lesions. lial dysfunction/damage. The tendency for Besides these cellular components, the major- atherosclerotic plaque to form at the carotid ity of carotid plaques have a necrotic core con- bifurcation is related to a number of factors, sisting of loose cellular debris and cholesterol including geometry, velocity profile, and shear crystals. The necrotic core is separated from the stress. carotid lumen by a fibrous cap, which is com- It was originally proposed that local turbu- posed of a rim of variable thickness comprising lence predisposed to high wall shear stress and cellular components and extracellular matrix. endothelial injury. This hypothesis, however, The structural integrity of the fibrous cap is was refuted by Zarins et al. (1983), who showed crucial to the final stage of plaque disruption that plaque formation was increased within and its clinical and pathological sequelae. It is areas of low flow velocity and low shear stress now generally accepted that acute changes and decreased in areas of high flow velocity and within the plaque, notably fissuring/splitting elevated shear stress. Postmortem specimens of the fibrous cap (Fig. 15.2), with exposure of showed that atherosclerosis was particularly the deeper lipid contents predisposes toward pronounced along the outer (lateral) aspect of thrombosis with or without secondary emboli- the proximal ICA and carotid bulb. This zone zation. It is not known what actually pre- corresponds to areas of low velocity and low disposes toward acute plaque disruption, but shear stress. The medial or inner aspect of the recent studies suggest that excess matrix metal- carotid bulb (associated with high blood flow loproteinase activity or cytokine expression 158

VASCULAR SURGERY within the plaque may be associated with this subtype predominantly affects the ICA and process (Loftus et al., 2002). renal arteries and may be associated with Another feature characteristic of advanced secondary aneurysm formation. atherosclerotic plaques is intraplaque hemor- rhage that can occur in the absence of a dis- Coils and Kinks of the Extracranial rupted fibrous cap. Symptomatic carotid disease is associated with increased neovascularization Carotid Arteries within the atherosclerotic plaque and fibrous cap. These vessels are larger and more irregular Redundancy of the extracranial carotid artery and may contribute to plaque instability and the is thought to be due to abnormalities in devel- onset of thromboembolic sequelae. opment. Occasionally, the ICA may undergo a complete 360-degree rotation. The ICA is derived embryologically from the third aortic Fibromuscular Dysplasia arch and the dorsal aortic root. In its early Fibromuscular dysplasia (FMD) is the com- stages, a normally occurring redundancy is monest nonatherosclerotic disease to affect straightened as the heart and great vessels the ICA. Approximately one quarter of patients descend into the mediastinum. Incomplete with carotid FMD have associated intracranial descent of the heart and great vessels may result aneurysms, and up to two thirds of these in the development of complex coils and kinks. patients will have bilateral carotid fibromuscu- These are bilateral in approximately 50% of lar dysplasia. affected patients. Fibromuscular dysplasia can be divided into Elongation of the ICA, which can also result three pathological subtypes. Medial fibroplasia in kinking of the ICA, is usually due to degen- is the most common (>85% of cases) and is erative changes associated with increasing age usually found in long segment arteries with few and atherosclerosis. The loss of elasticity of the side branches. It is characterized by stenoses arterial wall due to the aging process (coupled alternating with intervening fusiform dilata- with hemodynamic shear stresses) predisposes tions that resemble a string of beads, particu- toward kinks of the elongated carotid artery larly in the upper ICA. Pathologically, smooth between the proximal and distal fixed points of muscle cells in the outer media are replaced the skull base and thoracic inlet. by compact fibrous connective tissue, whereas the inner media contains excess collagen and Carotid Artery Aneurysms ground substance in disorganized smooth muscle cells. Because of its prevalence in As with aneurysms anywhere else in the body, females, a possible role for estrogen and prog- carotid aneurysms may be either true or false. esterone has been postulated. Others have sug- In the past,most true aneurysms (Fig.15.3) have gested that the absence of vasa vasorum in long traditionally been classified as part of the nonbranching arteries such as the ICA or renal atherosclerotic process, but emerging evidence arteries may predispose to mural ischemia suggests that aneurysmal disease may be yet that leads to the development of fibromuscular another manifestation of abnormalities of dysplasia. matrix metalloproteinase enzyme expression Intimal fibroplasia accounts for less than 10% and production, unless associated with other of cases of FMD and affects men and women distinct pathologies,for example,arteritis (giant equally. It typically appears as a focal narrowing cell, Takayasu) or FMD. False aneurysms may in older patients and long segmental stenoses in arise as a consequence of iatrogenic injury,blunt younger patients. The lesion is confined to the trauma, spontaneous dissection, or infection intimal layer while the medial and adventitial (e.g., prosthetic patch infection after carotid structures are always normal. Its pathophysiol- endarterectomy). ogy is due to irregularly aligned subendothelial mesenchymal cells within a loose matrix of con- Carotid Dissection nective tissue. Perimedial dysplasia is char- acterized by accumulation of elastic tissue Acute carotid dissection can complicate athero- between the media and the adventitia. This sclerosis, FMD, cystic medial necrosis, or blunt 159

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more prevalent in Asia and usually affects young females. Its pathogenesis relates to an inflam- matory process involving all three layers of the arterial wall with proliferation of connective tissue and degeneration of the elastic fibers. Granulomatous lesions may also develop, and the condition may also be associated with fusi- form or saccular aneurysms. Takayasu’s arteritis is classified according to its mode of involvement. Type I involves branches of the aortic arch; type IIa involves the , aortic arch, and branches; type IIb involves the vessels involved in IIa plus the descending aorta; type III involves the descend- ing thoracic aorta and abdominal aorta (with or without renal arteries); type IV involves the abdominal aorta (with or without renal arter- ies) and type V involves a combination of type IIb and IV.

Figure 15.3. Intraarterial digital subtraction angiogram of the aortic arch and great vessels. There is a large aneurysm just beyond the left carotid bifurcation.

trauma,or be associated with a collagen vascular disorder such as Ehlers-Danlos syndrome type IV or Marfan syndrome. Angiographic studies suggest that the most likely mechanism is an intimal tear followed by an acute intimal dissec- tion, which produces luminal occlusion due to secondary thrombosis within the false lumen. This appears as a flame-shaped occlusion 2 to 3 cm beyond the bifurcation (Fig. 15.4). Autopsy studies typically reveal a sharply demarcated transition between the normal carotid artery and the dissected carotid segment. The ICA is commonly affected, with the dissection plane typically occurring in the outer medial layer. The classical triad of clinical signs/symptoms following carotid dissection include (1) pain in the face and neck (20%), (2) a partial Horner syndrome (50%), and (3) retinal or cerebral ischemia (50% to 90%). About one in ten will suffer cranial nerve palsy. Takayasu’s Arteritis Figure 15.4. Selective intraarterial digital subtraction angio- Takayasu’s arteritis (TA) is a nonspecific arteri- gram in a patient with acute carotid dissection. The internal tis affecting the thoracic and abdominal aorta carotid artery is almost completely occluded 2 to 3cm beyond and their major branches. Although this dis- the origin of the internal carotid artery.There is virtually no flow ease is uncommon in Western countries, it is visible up the true lumen. 160

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Giant Cell Arteritis Carotid Body Tumor Giant cell arteritis predominantly affects elderly Carotid body tumors (CBTs) originate from the women. Although it commonly involves the chemoreceptor cells located at the carotid bifur- temporal arteries, it can involve other major cation. Because cells of the carotid body typi- vessels including the carotid artery and upper cally detect change in the PO2, PCO2, and pH, extremity vasculature. There is usually ten- CBTs have been reported to be more prevalent derness over the inflamed artery. Laboratory in individuals who live at high altitudes, which evaluation generally reveals elevation of C- suggests that chronic hypoxia may be an etio- reactive protein and the erythrocyte sedimenta- logical factor. A CBT typically presents as a tion rate. Biopsy of an affected artery shows palpable, painless mass over the carotid bifur- characteristic giant cell granulomata with abun- cation region in the neck. Cranial nerve palsy dant T lymphocytes. However, a negative biopsy may occur in up to 25% of patients, particularly does not exclude the diagnosis. Management involving the vagus and hypoglossal nerves. of giant cell arteritis usually includes the use of The differential diagnosis includes cervical high-dose corticosteroids as well as other forms lymphadenopathy, carotid artery aneurysm, of immunosuppression including cyclophos- branchial cleft cyst, laryngeal carcinoma, and phamide or azathioprine. Steroids can usually metastatic tumor. be tailed off after 1 year of treatment. The treatment of choice of CBT is surgical excision. Because these tumors are highly vas- cularized, preoperative tumor embolization has Radiation Arteritis been advocated by some surgeons to minimize operative blood loss when dealing with tumors The principal effects of radiation on arteries >3cm in diameter, but there is no consensus on include immediate arterial spasm and endo- this strategy. An important surgical principle in thelial denudation, intimal disruption, sub- CBT resection is to maintain the plane of dis- intimal edema,and degeneration of collagen and section within the subadventitial space, which smooth muscle. These acute changes predispose enables complete tumor excision without inter- toward an increase in vessel wall permeability to rupting carotid artery integrity. circulating lipids, which produce a plaque char- acterized by fibrosis,fatty infiltration,and elastic tissue destruction. Hyperlipidemia and hyper- Carotid Trauma cholesterolemia appear to predispose patients who have received radiation therapy to develop Blunt trauma to the neck can cause carotid accelerated atherosclerotic lesions. The sensitiv- artery injury either by forceful compression ity of elastic tissue to radiation may account for or extension of the artery. Common scenar- the mechanism of structural weakening and ios include motor vehicle or motorcycle eventual rupture in elastic arteries. accidents, pedestrian injuries, hanging, or As a result of the increased use of external strangulation. radiation to treat neck malignancies, a rise in Patients with carotid trauma may present radiation-induced atherosclerotic disease in with focal physical findings such as neck hema- association with symptomatic carotid stenosis toma, pulsatile cervical mass, carotid bruit, or has been noted. Radiation-induced carotid localized bleeding. More generalized physical lesions can present either in a segmental or findings include loss of consciousness and lat- diffuse manner. The affected carotid segments eralizing neurological deficits. Arteriography typically lie within the field of radiation treat- remains the diagnostic test of choice for carotid ment.One or both common carotid arteries may trauma, since it has the highest sensitivity be involved, whereas the carotid bifurcation is and specificity compared to all other imaging often spared. The severity of carotid injury is modalities. Treatment of all blunt carotid artery related to radiation dose. Smaller doses cause injuries usually involves anticoagulation. Anti- less cellular damage, whereas larger doses may platelet therapy should be considered if sys- even lead to arterial wall necrosis. temic anticoagulation is contraindicated. 161

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Clinical Presentation Nonhemispheric Symptoms of Carotid Disease These are a group of nonfocal symptoms that, on their own, are not indicative of true carotid Syndromes or vertebrobasilar events. Classical nonhemi- spheric symptoms include isolated dizziness, Transient Ischemic Attack isolated vertigo, isolated syncope (drop attacks, blackouts), isolated double vision (diplopia), A transient ischemic attack is a focal loss of neu- and presyncope (faintness). In the absence of < rological function (lasting 24 hours) that has a any corroborative carotid or vertebrobasilar vascular cause upon investigation. It is conven- symptoms, they cannot be ascribed to extracra- tional to describe a TIA as being carotid or ver- nial carotid or vertebral disease alone. tebrobasilar (see below). Clinical Features Completed Stroke A completed stroke is a focal (occasionally Ocular Symptoms global) loss of neurological function, lasting Ocular symptoms associated with extracranial for more than 24 hours, that is found to have a carotid and vertebrobasilar disease include vascular cause upon investigation. The term amaurosis fugax (transient monocular blind- completed refers to the fact that the severity of ness), Hollenhorst plaques, retinal/optic nerve the neurological deficit has now reached its ischemia, the ocular ischemia syndrome, and maximum. visual field deficits secondary to cortical infarc- tion and ischemia of the optic tracts. The blood supply to the retina originates Stroke in Evolution from two sources. The short posterior ciliary arteries supply the outer two layers, together A stroke in evolution is a progressive worsening with the optic disk and optic nerve. The central of the neurological deficit, either linearly over a retinal artery supplies the inner layers of the 24-hour period or interspersed with transient retina. Amaurosis fugax is a temporary loss of periods of stabilization and/or partial clinical vision in one eye (likened to a shutter coming improvement. down), but which can also refer to graying of the vision. The blindness usually lasts for a few minutes and then resolves. Most (>90%) are Crescendo Transient Ischemic Attacks due to embolic occlusion of the main artery or This condition has never been properly defined. its upper/lower divisions. It remains unclear, Traditionally, it refers to a syndrome compris- however, why some patients always have ing repeated TIAs within a short period of repeated episodes of amaurosis and never time with complete neurological recovery in hemispheric signs. between. At a minimum, the term should prob- Monocular blindness progressing over a 20- ably be reserved for those with daily events. minute period suggests a migrainous etiology. Hemodynamic amaurosis is rare but can be pre- cipitated by heavy exercise or arising from a hot Hemodynamic Transient Ischemic Attacks bath. In this situation, where there is a severe carotid stenosis and poor collateralization, the These attacks are focal cerebral events (hemi- visual loss tends to start at the periphery and sensory or retinal) that are aggravated by exer- move toward the center. Occasionally, a patient cise or hemodynamic stress and typically occur recalls no visual symptoms, but the optician after short bursts of physical activity, post- notes a yellowish plaque within the retinal prandially or after getting out of a hot bath. It vessels (the Hollenhorst plaque). This is fre- is implied that they are due to severe extra- quently derived from cholesterol embolization cranial disease and poor intracranial collateral from the carotid bifurcation and it warrants recruitment. further investigation (Fig. 15.5). 162

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the optic tracts. Occipital lesions cause a con- gruous homonymous hemianopia (visual field defects exactly overlap in each eye). Homony- mous hemianopia involving the lower visual fields is usually due to a parietal infarction and follows ischemia of the upper fibers of the visual pathway that traverse the parietal lobe. Con- versely, temporal lobe infarcts can extend to involve the lower fibers of the visual pathways and so cause a hemianopia involving the upper fields. Of practical importance is the observa- tion that homonymous hemianopia secondary to occipital lesions tends to cause a very per- ceptible visual void to the patient. In contrast, the patient with homonymous hemianopia due to parietal or temporal lobe lesions is often unaware of the deficit and may bump into objects. Figure 15.5. Funduscopic examination. Note the two choles- terol emboli within the retinal vessels. Motor/Sensory Symptoms A number of cerebral pathologies can cause Monocular visual loss due to central retinal motor or sensory symptoms that may mimic artery occlusion, persisting for more than 24 the focal symptoms observed in TIA or stroke. hours is analogous to cerebral infarction, with These primarily include intracranial hemor- the occlusive process usually occurring in the rhage, tumor, migrainous phenomena, and intraneural part of the central retinal artery. In arteritis. Overall, the pattern of onset in con- addition to an embolic etiology, it is also impor- junction with the distribution and nature of tant to consider microatheroma, and arteritis in the symptoms enables the clinician to be more occasional patients with other atypical symp- discriminating in developing a differential toms. Bilateral visual loss (cortical blindness) diagnosis. is due to infarction of the visual cortex in the Ischemic events tend to have an abrupt onset, occipital lobe and therefore is never a carotid with the severity of the insult being apparent territory event. from the outset. By contrast, motor/sensory The optic nerve head can be rendered signs associated with migraine often progress ischemic by thromboembolic phenomena, from one part of the body to the next over a although it is rarely due to extracranial carotid 15- to 20-minute period of time. Ischemic artery disease. Optic nerve ischemia is usually TIAs rarely include positive phenomena. For due to intrinsic disease of the short posterior example, the hemisensory/motor signs with ciliary arteries and can present as an acute loss ischemic TIAs are not usually associated with of either central or peripheral vision in one seizure or paresthesia but represent loss or eye. If the upper or lower visual fields are lost, diminution of neurological function. Migrain- this suggests occlusion of the upper and lower ous or postictal events frequently include branch divisions of the ciliary artery. seizures, clonic contractions, and enhanced The ocular-ischemia syndrome is a relatively sensory phenomena. rare condition where there is global under- Motor/sensory deficits can be unilateral or perfusion of the eye, deteriorating monocular bilateral, with the upper and lower limbs being vision, and excessive proliferation of the con- variably affected depending on the site of the junctival vessels. It is indicative of extremely cerebral lesion. For example, occlusion of the poor eye collateralization. anterior cerebral artery causes a hemiparesis, Homonymous hemianopia can occur as a with the leg being more severely affected than consequence of ischemia at varying points in the arm. The combination of a motor and 163

CAROTID ARTERY DISEASE sensory deficit in the same body territory is sug- motor/sensory symptoms, bilateral visual loss, gestive of a cortical thromboembolic event as homonymous hemianopia, dysarthria, nystag- opposed to lacunar lesions secondary to small- mus, ataxia and gait problems, dysphagia and vessel disease of the penetrating arterioles. dizziness, and vertigo, provided they accom- However, a small proportion of the latter may pany other vertebrobasilar features. present with a sensorimotor stroke secondary to Discrimination between carotid and verte- small-vessel occlusion within the posterior limb brobasilar symptoms is usually straightfor- of the internal capsule. Pure sensory and pure ward but can be difficult. For example, 10% motor strokes and those strokes where the of patients with vertebrobasilar stroke have weakness affects one limb only or does not hemisensory/motor signs. This is because of involve the face are more typically seen with anatomical variations in the vascular boundary lacunar as opposed to cortical infarction. zones between the carotid and vertebrobasilar system. Similarly, a small number of patients with thromboembolic carotid artery disease Higher Cortical Dysfunction present with vertebrobasilar symptoms because the posterior cerebral artery is embryologically A number of clinical phenomena, including derived from the carotid artery as opposed to speech and language disturbances, can be the vertebrobasilar system. If there is any ques- caused by thromboembolic phenomena within tion regarding interpretation of the clinical the anterior and posterior circulations. There picture, advice from a neurologist or stroke are a large number of examples of higher corti- physician should be sought. cal dysfunction (dysphasia, apraxia, visuospa- tial neglect, alexia) that are beyond the scope of this review. However, the most important clini- Clinical Features of cal example for the dominant hemisphere is expressive dysphasia/aphasia, with visuospatial Nonatherosclerotic Disease neglect being an example of nondominant One of the characteristic features of the non- hemisphere injury. atherosclerotic pathologies listed earlier is the Dysphasia is a language disorder as opposed potential for thrombosis/stenosis and aneurysm to dysarthria, which is a locomotor speech formation. Accordingly, each condition can problem. Differentiation between the two is im- cause ischemic stroke/TIA, but most are rela- portant, as dysarthria is a vertebrobasilar symp- tively rare. The onset of stroke/TIA in a patient tom whereas dysphasia is of carotid origin. exhibiting other atypical features should raise In expressive dysphasia, patients know what the possibility of a nonatheromatous pathology. they wish to say but either cannot find the Sudden onset of temporal headache or neck word or produce seemingly meaningless verbal pain associated with a neurological or visual output. Dysarthria can be defined as a simple deficit is suggestive of carotid dissection. The inability to “get your tongue” around the word. initial neurological symptoms are thought to Visuospatial neglect is the result of injury to be due to acute expansion of the dissection the nondominant parietal lobe. Here patients resulting in compression of cranial nerves IX, may exhibit inattention to one side of their X, XI, or XII, followed by cerebral ischemia. body. Horner syndrome can also occur, which is believed to be due to disruption of periadventi- Carotid or Vertebrobasilar Territory? tial sympathetic fibers adjacent to the carotid artery. Systemic illness, malaise, weight loss, Typical carotid territory symptoms (anterior and myalgia suggest an underlying arteritis and middle cerebral arteries) include hemi- (Takayasu, giant cell, SLE, polyarteritis). Jaw sensory/motor symptoms, amaurosis fugax, claudication is an important presentation in and evidence of higher cortical dysfunction. giant cell arteritis. Takayasu arteritis patients Homonymous hemianopia alone is not a fea- also present with symptoms attributable to ture of injury to the carotid territory. Classical involved vascular beds (renovascular hyperten- vertebrobasilar symptoms comprise bilateral sion, TIA/stroke, MI). 164

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Prognosis of Ischemic Stroke Patients classified as lacunar infarction (LACI) presented with symptoms and signs Mortality and Persisting Disability associated with disease of the deep perforating arteries (pure motor stroke, pure sensory Stroke is the commonest cause of persisting stroke, sensorimotor stroke, and ataxic hemi- neurological disability in the Western world paresis).Patients with LACI never have evidence and accounts for 4.5 million deaths per annum of higher cortical dysfunction and major vessel worldwide. The overall mortality rate for stroke occlusion was not a feature. is about 26% at 30 days and 38% at 1 year, but Patients classified as posterior circulation varies according to subtype (see below). infarction (PoCI) presented with vertebrobasi- At 6 months, 15% to 25% of stroke survivors lar symptoms and had infarcts localized to the are still dysphasic/aphasic, 7% to 11% remain posterior circulation territory. The 30-day mor- incontinent of urine or feces, up to 33% require tality rate was 7%, and 80% were independent at help with dressing/feeding or toileting, 15% 30 days. are unable to walk independently indoors, and 17% are classified as moderately or severely disabled. Investigation of Outcome Based on Presentation Ischemic Stroke The Oxfordshire Community Stroke Project All patients should undergo simple baseline (OCSP) was the first community-based study to investigations (full blood count, urea/elec- develop a bedside classification that could reli- trolytes, glucose, lipids, chest x-ray, electro- ably predict outcome, vascular pathology, and cardiogram). This not only enables diagnosis of CT scan/autopsy findings following ischemic unexpected coexistent pathologies (sickle cell stroke (Bamford et al., 1990). Patients who were disease, thrombocytosis, etc.), but also enables classified as total anterior circulation infarction important risk factors to be corrected (hyper- (TACI) presented with the triad of (1) hemi- tension, diabetes, ischemic heart disease, etc.). sensory/motor deficit affecting the face, arm, There is no need for more complex investiga- and leg; (2) homonymous hemianopia; and tions to be performed routinely (autoantibod- (3) higher cortical dysfunction (e.g., dysphasia, ies, echocardiograms, thrombophilia screens). visuospatial neglect). These patients had the These should only be undertaken if the history largest infarction volumes on CT scan or or initial investigations suggest it is appropriate. autopsy, occlusion of either the extracranial ICA or intracranial MCA mainstem, and a 30-day Duplex Ultrasound mortality rate of 37%. Only 7% were alive and independent at 1 year. Patients with TACI are Noninvasive diagnostic testing should be per- rarely ever candidates for carotid surgery. formed in the preliminary evaluation of all pa- Patients presenting with one or two compo- tients suspected of having suffered a stroke or nents of the TACI triad were classified as partial TIA. Color duplex is now the most accessible anterior circulation infarction (PACI). These screening technique for diagnosing carotid patients had focal, cortical infarcts on CT scan stenosis. One of the great advantages of duplex and rarely had evidence of major vessel occlu- is that the machine can be brought down into a sion. The majority followed embolization of single visit outpatient clinic. Duplex combines MCA branches from a carotid plaque. The 30- B-mode imaging and pulsed wave Doppler sam- day mortality following PACI was 13%, and 71% pling of velocity spectra to assess the potential were alive and independent at 1 year. Patients hemodynamic significance of the carotid lesion. with a nondisabling PACI stroke were exposed Indications for carotid duplex scanning typi- to a 5% risk of recurrent stroke within 30 days cally fall into three categories: symptoms, signs, of the initial event and a 17% risk of stroke and risk factors. Symptoms include those that within 1 year. Patients with PACI constitute define a classic TIA. The primary sign is the the majority of patients being considered for presence of a carotid bruit, whereas risk factors carotid endarterectomy. include diabetes mellitus, hypertension, ciga- 165

CAROTID ARTERY DISEASE rette smoking,hypercholesterolemia,peripheral signal against the black background. Two- vascular disease,and coronary artery disease.As dimensional (2D) TOF involves the sequential the number of risk factors increases, the likeli- acquisition of tomographic slices of data that hood of an associated carotid lesion rises. are then reconstructed by a computer algorithm The accuracy of a carotid duplex scan is to create the axial angiogram. Three-dimen- largely dependent on the technician who per- sional (3D) TOF acquires multiple slices of data forms the study, as well as the type of scanner at the same time. Each has its advantages and that is used. Ultrasound criteria vary among disadvantages. Two-dimensional TOF is better units, and each vascular laboratory should vali- at discriminating abnormalities within fields of date the technical skills of the ultrasonographer slow flowing blood. Therefore, it is useful in dif- before duplex imaging is used as the sole diag- ferentiating subtotal occlusion from complete nostic study. occlusion. It is, however, limited by its inability An increasing number of units now perform to reliably interpret kinks and loops, and the carotid surgery on the basis of duplex ultra- creation of flow voids tends to lead to overin- sound alone. However, corroborative magnetic terpretation of stenosis degree. The latter is not resonance angiography (MRA) or diagnostic a problem with 3D TOF. As with duplex, advo- angiography may be required in patients with cates of MRA must validate their own findings (1) gross calcification causing severe acoustic with either angiography or resected plaque shadowing, (2) inability to image proximal or specimens. distal limits of plaque, (3) damped inflow wave- form suggestive of proximal common carotid disease, and (4) a high-resistance ICA waveform Contrast Angiography suggestive of distal severe disease. Some units Few centers now perform routine contrast may still wish to undertake corroborative angiography on all patients prior to surgery. studies in patients with a duplex diagnosis of This is partly due to the inevitable delay, but ICA occlusion. mainly because of the potential for angio- graphic-related strokes. This risk is between 1% Magnetic Resonance Angiography and 2%. Interestingly, 50% of the operative risk in the Asymptomatic Carotid Atherosclerosis The principal advantages of MRA are that no Study was attributable to the angiographic radiation is involved, it can be combined with stroke risk. The risk of angiographic stroke is functional brain imaging, and the surgeon is reduced by (1) employing arch injections where provided with a hardcopy for easy interpre- possible, (2) using small volumes of nonionic tation. Disadvantages include problems with contrast material,(3) using small bore catheters, interpretation of images and, more importantly, (4) using experienced practitioners, and (5) rapid access to imaging in TIA clinics. being sure the patients are well hydrated. The principle underlying MRA is that the Intraarterial digital subtraction arteriogra- patient is positioned within a magnetic field. phy (DSA) is still indicated in patients in This causes protons in the body’s water mole- whom there is discordance between duplex and cules in the area of interest to become aligned MRA or problems with interpretation of these with their axis to the magnetic field. Radio wave modalities. pulses are then applied to the region of interest that excite the protons and cause them to rotate. As the protons return to their original align- Functional Imaging ment they emit energy that is picked up by external detectors. There are two principal This is another contentious issue. Some centers methods for imaging blood vessels: time of advocate routine CT or magnetic resonance flight (TOF) and phase contrast. imaging (MRI) on all stroke/TIA patients on the In the TOF method, stationary tissue is dark basis that unexpected pathology (neoplasms, because the repeated radio wave pulsations sat- vascular malformations, subarachnoid or sub- urate their signal. In contrast, flowing blood dural hematomas) must be considered in the emerging from the chest has not been subject to overall differential diagnosis. Others argue that the radio waves and is represented by a white the yield is <2%, it incurs an unnecessary delay, 166

VASCULAR SURGERY it does not alter management decisions, and it There has been much debate about the incurs undue cost. optimal aspirin dose. A balance must be struck, In an ideal world, all patients should undergo as there is a 1.0% annual risk of adverse events functional imaging (preferably MRI) combined associated with aspirin therapy, with the risk with MRA. However, all clinicians would agree increasing as the aspirin dose increases. In that patients presenting with a stroke require Europe, there is a trend toward using low-dose imaging within 2 weeks of onset (so as to iden- aspirin (50 to 150mg daily), whereas larger tify patients with intracranial hemorrhage), as doses have previously been recommended in should patients reporting atypical symptoms North America (300 to 1200mg). Meta-analyses (seizure, progressive neurological symptoms, have shown that aspirin doses of <100mg daily headaches, cranial nerve signs). Centers that confer a 13% RRR in subsequent vascular events continue to advocate routine CT/MRI must in patients with a presenting history of stroke or ensure that implementation of such a policy TIA, falling to 9% for medium doses (300mg does not lead to unacceptable delays in planning daily) and 14% for daily doses in excess of 900 management strategies. mg. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) originally observed that the incidence of perioperative Management of Occlusive stroke was significantly higher in patients receiving lower-dose aspirin. However, a sub- Carotid Artery Disease sequent randomized trial in more than 2500 patients undergoing carotid endarterectomy Best Medical Therapy indicated that the 30-day risk of stroke, MI, or death was significantly lower in patients taking There is more to investigating and treating 81mg or 325mg aspirin as compared with 650 patients with stroke or TIA than simply identi- to 1300mg. fying those who might benefit from carotid Dipyridamole inhibits platelet aggregation by endarterectomy. More importantly, the imple- partially blocking the adenosine diphosphate mentation of the best medical therapy should (ADP) receptor on the platelet and by elevat- not be delegated to the most junior member of ing levels of cyclic adenosine monophosphate the team. Although some risk factors (age, sex, (cAMP) and cyclic guanosine monophosphate gender, family history) are nonmodifiable, there (cGMP). Dipyridamole on its own does not is an increasing body of systematic evidence to significantly reduce the risk of secondary guide the clinician with regard to implementing stroke, but a number of studies have suggested optimal medical therapy in patients with cere- that combination therapy with aspirin is more bral vascular disease. effective. This has been confirmed in a recent meta-analysis that showed that aspirin and Antiplatelet Therapy dipyridamole conferred a 23% RRR in stroke. However, the benefit was slightly offset by the Aspirin irreversibly blocks cyclooxygenase- fact that about a quarter of patients experienced mediated breakdown of arachidonic acid, adverse side effects, necessitating dipyridamole thereby inhibiting the formation of thrombox- withdrawal. ane A2 (platelet aggregator and vasoconstric- Ticlopidine and clopidogrel have similar tor).Meta-analyses have shown no evidence that modes of action. Both inhibit platelet activation aspirin has any beneficial role in the primary through inhibition of ADP binding to its platelet prevention of stroke. However, in patients with receptor, thereby blocking the GpIIb-IIIa re- a history of vascular disease, the Antiplatelet ceptor complex that is the principal receptor Trialists’ Collaboration showed that aspirin con- for platelet fibrinogen binding. Although some ferred a 22% relative risk reduction (RRR) in all studies showed a beneficial reduction in the vascular events (nonfatal stroke, nonfatal MI, risk of stroke, an overview by the Antiplatelet vascular death). A more recent meta-analysis Trialists’ Collaboration suggested that ticlopi- has shown that aspirin confers a 15% reduction dine conferred no extra benefit over aspirin in stroke alone in patients presenting with alone in terms of reducing the risk of all vascu- symptomatic cerebral vascular disease. lar events. However, ticlopidine was associated 167

CAROTID ARTERY DISEASE with a 20% incidence of adverse complications There remains some controversy over the including neutropenia in 2% and a tendency threshold for therapeutic intervention in to increased cholesterol levels. Overall, 6% of patients with hypertension. In the U.S., the patients had to stop the drug. recommendation is to maintain blood pressure Clopidogrel is the newest antiplatelet agent less than 140/90mmHg, whereas in the U.K. and has a greater antiplatelet effect than ticlopi- the advice is for control to also reflect the age of dine. Although the CAPRIE study observed a the patient. The exception might be the diabetic significant reduction in the incidence of vascu- patient with hypertension who warrants more lar events in favor of clopidogrel (75mg daily),as careful control of blood pressure (see below). compared with aspirin (325mg daily), it should The one other golden rule is that patients be borne in mind that the relative risk reduc- undergoing carotid endarterectomy should not tion was 8.7%, the absolute risk reduction only undergo surgery with uncontrolled hyperten- 0.5%, and subgroup analyses failed to show a sion, as this is associated with a twofold excess significant reduction in stroke risk relative to all risk of perioperative stroke. vascular events (CAPRIE Steering Committee, 1996). In the U.K., a course of clopidogrel is 30 times more expensive than aspirin. Smoking In summary, aspirin remains the antiplatelet For obvious reasons, there have never been agent of choice. The dose should be between 75 any randomized trials comparing stroke risk and 300mg daily, and therapy should continue in patients who continue to smoke! A meta- throughout the perioperative period in patients analysis of epidemiological and cohort studies undergoing carotid endarterectomy. Medically indicates that the relative risk of stroke is treated patients who suffer repeated throm- doubled in smokers as opposed to nonsmokers. boembolic events while on aspirin should either The excess risk of stroke declines with time after have dipyridamole (200mg) added to the smoking cessation and is equivalent to that of aspirin regime or convert to clopidogrel (75mg nonsmokers after about 5 years. daily).Clopidogrel is preferable to dipyridamole alone in patients who are aspirin intolerant. Surgeons, however, should be aware that clop- Diabetes idogrel trebles the bleeding time whereas a combination of aspirin and full-dose clopido- Diabetes is associated with a twofold excess grel increases the bleeding time by a factor of risk of stroke, and, intuitively, one would have five as compared with aspirin alone. thought that careful glycemic control would be associated with a significant reduction in stroke risk. However, one of the few randomized trials Treatment of Hypertension to address this issue showed that the risk of late A systematic review of randomized trials com- stroke appeared to be unchanged in patients prising 48,000 hypertensive patients found that randomized to aggressive glycemic control. The a sustained reduction of 5mmHg in diastolic available evidence suggests that it is the hyper- blood pressure over a 3-year period was asso- tensive type 2 diabetic who is most at risk of late ciated with a 38% reduction in the risk of stroke. The U.K. Prospective Diabetes Study late stroke (Collins and MacMahon, 1994). How- Group randomized hypertensive,type 2 diabetic ever, relatively few of these patients had a prior patients to strict antihypertensive therapy history of stroke or TIA. More recently, the (mean blood pressure 144/82mmHg) or less Antithrombotic Trialists’ Collaboration per- stringent control (mean blood pressure 154/ formed a review of the randomized trial data 87mmHg). During follow-up, the former strat- from 150,000 patients with cerebral or coronary egy was associated with a 44% reduction in late events, and found that for every 5mmHg reduc- stroke. tion in the diastolic blood pressure, there was a 15% relative reduction in the risk of stroke. Treatment of Atrial Fibrillation Interestingly, there was no evidence of a lower diastolic threshold below which the risk of About 20% of all strokes are secondary to non- stroke did not fall. valvular atrial fibrillation (NVAF). Approxi- 168

VASCULAR SURGERY mately 5% of the population aged >65 years therapy was associated with a 25% reduction in have NVAF, incurring a 3% to 5% annual risk of the risk of late stroke, but only in those patients stroke. Treatment with warfarin reduces the risk with coexistent symptomatic ischemic heart of stroke by 68% but decisions regarding the disease. The principal problem regarding plan- role of anticoagulation must take into account ning lipid lowering therapy based on evidence the potential hemorrhagic risks. The annual is that most of the randomized trials have been risk of significant bleeding in anticoagulated undertaken in patients with coronary heart patients is 1.3%, including a 0.3% incidence of disease. Few have specifically examined the role intracranial hemorrhage. Patients at increased of statin therapy in patients with TIA or stroke, risk of significant hemorrhage include those although several should be reporting in the next with the following findings: a previous history year or so. of bleeding, age >75 years, an international nor- In the U.K., there is conflicting advice regard- malized ratio (INR) >3.0, fluctuating INRs, and ing statin therapy. The National Service Frame- uncontrolled hypertension. work for Coronary Heart Disease recommends Although each case must be considered statin therapy (cholesterol to be reduced to individually, it is generally recommended that <5mmol/L) in all patients with coronary heart patients considered high risk for embolic disease or other occlusive disease (including stroke be warfarinized with a target INR of those with TIA or stroke irrespective of cardiac <3.0. High-risk patients (6% annual stroke risk) status). In contrast, the National Clinical Guide- include (1) those of any age with a past history lines for Stroke recommends therapeutic of TIA or stroke, rheumatic heart disease, intervention only in patients with symptomatic ischemic heart disease, and evidence of im- cerebrovascular disease and coronary heart paired left ventricular function on echocardio- disease. This conflicting advice will almost cer- graphy; and (2) patients aged >75 years with tainly be revised following the recent publica- hypertension and/or diabetes. Low-risk patients tion of the British Heart Protection Study. This (1% annual stroke risk), including patients trial randomized 20,000 patients with vasc- aged <65 years with no risk factors, should be ular disease (including stroke/TIA) to placebo treated with aspirin. The medium-risk group or simvastatin (40mg daily). Overall, statin (2% annual stroke risk) are more difficult to therapy conferred a 12% reduction in all mor- categorize. It comprises (1) those aged <65 years tality, a 17% reduction in vascular mortality, a with a history of diabetes, hypertension, periph- 24% reduction in all coronary events, and a 27% eral vascular disease, and ischemic heart dis- reduction in stroke.Of most importance was the ease who should be warfarinized; and (2) those observation that there did not appear to be any aged 65 to 75 with no risk factors in whom it lower cholesterol limit below which benefit was might be reasonable to treat with aspirin. not observed. Aspirin therapy should be considered in all In the U.S., statin therapy is advised in all patients with NVAF who are unable to take patients with TIA/stroke and coronary heart warfarin. disease. In patients with no coronary heart dis- ease and fewer than two vascular risk factors (selected from men aged >45 years, women aged Treatment of Hyperlipidemia >55 years, family history of heart disease, smoking, hypertension, diabetes, high-density In a meta-analysis of the available epidemiolog- lipoprotein (HDL) cholesterol <35mg/dL), the ical studies (450,000 patients), no association advice is to try dietary modification for 6 was observed between cholesterol level and months and to introduce statin therapy only if overall stroke rate. However, meaningful inter- the low-density lipoprotein (LDL) cholesterol pretation of these data was confounded by the is >190mg/dL with a target of <160mg/dL. The fact that although a higher cholesterol level was TIA/stroke patients with no history of coronary associated with an increased risk of ischemic heart disease (but having more than two risk stroke, this was offset by an increased risk of factors) should undergo dietary modification hemorrhagic stroke in patients with lower for 6 months followed by statin therapy if the cholesterol levels. A subsequent systematic re- LDL cholesterol is >160mg/dL with a target of view of randomized trials indicated that statin reducing it to <130mg/dL. 169

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Surgery for Occlusive disease ning and contrast angiography. Follow-up was coordinated by the neurologists and stroke Carotid endarterectomy (CEA) is one of the few physicians. surgical procedures to have been subjected to The basic results are summarized in Table evidence-based scrutiny with large, multicenter 15.1. Both trials showed that CEA conferred randomized trials. An overview of the principal significant benefit in symptomatic patients with results from the European Carotid Surgery Trial a 70% to 99% stenosis. The ECST found no evi- (ECST), the NASCET, and the Asymptomatic dence of benefit in patients with lesser degrees Carotid Atherosclerosis Study (ACAS) is pre- of disease. The NASCET observed a small but sented below. One other carotid surgical pro- significant benefit in patients with 50% to 69% cedure (extracranial–intracranial bypass) has stenoses. The reason for these apparent discrep- been intermittently advocated for recurrent ancies lies in the method for calculating degree TIAs/stroke in the presence of a chronically of stenosis. The ECST compared the residual occluded ICA. This procedure was popularized luminal diameter against the diameter of the during the 1980s, but a randomized trial there- carotid artery at the level of the stenosis (usually after showed no level I evidence of benefit. The the carotid bulb). The NASCET compared the methodology of this study has been challenged residual luminal diameter against the diameter but few surgeons currently advocate this form of of the ICA at least 1cm above the stenosis. surgery. As a consequence, the ECST tends to systemati- cally overestimate stenoses (as compared with the NASCET method), particularly in those Overview of ECST and NASCET with mild/moderate disease. In reality, a 50% NASCET stenosis is approximately equivalent to In ECST and NASCET almost 6000 patients a 65% ECST, whereas a 70% NASCET stenosis in over 200 centers around the world were equates to an 82% ECST. randomized, comparing “best medical therapy” The ECST and NASCET have identified against “best medical therapy” and CEA. All predictive factors that are associated with a patients had to have reported ipsilateral carotid significantly higher risk of late stroke in territory symptoms within the preceding 6 medically treated patients. These include male months; all were seen by a neurologist prior sex, 90% to 94% stenosis, surface irregularity/ to randomization and all underwent CT scan- ulceration, coexistent syphon or intracranial

Table 15.1. Long-term risk of ipsilateral stroke (including perioperative stroke or death) Trial stenosis Surgical risk Medical risk ARR RRR NNT Strokes prevented (%) (%) (%) (%) (%) per 1000 CEAs ECST <30% 9.8 at 5y 3.9 at 5y -5.9 n/a n/a n/a 30–49% 10.2 at 5y 8.2 at 5y -2.0 n/a n/a n/a 50–69% 15.0 at 5y 12.1 at 5y -2.9 n/a n/a n/a 70–99% 10.5 at 5y 19.0 at 5y +8.5 45 12 83 at 5y NASCET 30–49% 14.9 at 5y 18.7 at 5y +3.8 20 26 38 at 5y 50–69% 15.7 at 3y 22.2 at 3y +6.5 29 15 67 at 3y 70–99% 8.9 at 3y 28.3 at 3y +19.4 69 5 200 at 3y ACAS 60–99% 5.1 at 5y 11.0 at 5y +5.9 53 17 59 at 5y ACST 60–99% 6.4 at 5y 11.8 at 5y +5.4 46 19 53 at 5y

ARR, absolute risk reduction; RRR, relative risk reduction; NNT, number of CEAs to prevent one ipsilateral stroke at specified time interval; n/a = not applicable; y, years. 170

VASCULAR SURGERY disease, no recruitment of intracranial collat- systematic benefit from CEA. Near-occlusion erals, hemispheric symptoms, cerebral events was defined angiographically as severe stenosis within 2 months, multiple cerebral events, con- with evidence of reduced flow in the distal ICA tralateral occlusion, multiple concurrent risk (delayed arrival of contrast in the distal ICA or factors, and age >75 years. In contrast, a lower recruitment of collateral flow toward the symp- relative risk of stroke is observed in patients tomatic hemisphere, or both) and evidence of with lesser degrees of disease [70% to 79% narrowing of the poststenotic ICA (lumen stenosis (ECST), 50% to 69% (NASCET)], near diameter similar to, or less than, that of the occlusion with a string sign, smooth stenoses, ipsilateral external carotid artery and less than female sex, retinal symptoms, and those pre- that of the contralateral ICA). Accordingly, senting with lacunar stroke. there is increasing evidence that patients with A pooled analysis of data from the ECST, subocclusion and distal vessel collapse should NASCET, and the Veterans Affairs (VA) trial be treated conservatively. has recently been performed (Rothwell et al., 2003). All the angiograms were standardized to the NASCET method, and the overall database Overview of ACAS and ACST contained >6000 randomized patients. Table 15.2 summarizes the 30-day death/any stroke A number of randomized studies have evalu- rates following endarterectomy for each of the ated the role of CEA in patients with severe principal trials. Overall, 7.1% of patients [95% asymptomatic carotid artery disease (MACE, confidence interval (CI) 6.3–8.1] in the three CASANOVA,VA study), but ACAS and ACST are trials either died or suffered a stroke within 30 generally accepted to be the best (ACST, Lancet days of surgery. This is an important observa- 2004). The ACAS randomized 1600 patients with tion, as the track record for all participating asymptomatic 60% to 99% stenoses. Table 15.1 surgeons was vetted before they were allowed to summarizes the principal findings. Although randomize patients. there was a 53% RRR in late stroke, this only Figure 15.6 illustrates how the benefit of CEA equated to a 5.9% actual risk reduction at 5 increases with time and with increasing degrees years. Clinicians in North America and main- of stenosis. By contrast, CEA was harmful in land Europe have embraced the findings of patients with <50% stenoses. It conferred a ACAS more liberally than their U.K. or Scandi- small but significant benefit in symptomatic navian colleagues. In the latter countries, con- patients with 50% to 69% stenoses, with the cerns remain that the ACAS showed no benefit maximal benefit being observed in patients in women, there was no reduction in disabling with 70% to 99% stenoses. Note, however, that stroke, and (unlike ECST and NASCET) no rela- patients with near-occlusion did not derive any tionship between increasing stenosis and stroke

Table 15.2. Analysis of pooled data from the ECST, NASCET, and the Veterans Affairs trial: 30-day risk of death and/or stroke after carotid endarterectomy Trial <50% 50–69% ≥70% Near occlusion ECST 73/1044 37/371 17/249 3/78 7.0% (5.4–8.6) 10.0% (6.9–13.1) 6.8% (4.0–10.8) 3.8% (0.8–10.8) NASCET 43/663 30/421 14/261 5/70 6.5% (4.7–8.6) 7.1% (4.8–10) 5.4% (3.0–8.8) 7.1% (2.4–15) VA309 2/20 5/71 10.0% (1.2–3.2) 7.0% (2.3–15.7) Combined 116/1707 69/812 36/581 8/148 6.8% (5.6–8.0) 8.5% (6.6–10.5) 6.2% (4.4–8.5) 5.4% (2.4–10.4)

Note: The data shown are the observed percents.The 95% confidence interval is shown in parentheses. Source: Adapted from Rothwell et al. (2003). Here the individual data from each trial were reanalyzed and combined after having standardized all the angiograms to the NASCET method of stenosis measurement. 171

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% 45 ARR at 3 40 ARR at 5 35 ARR at 8 30 25 20 15 10 5 0 –5 <30% 30-49% 50-59% 60-69% 70-79% 80-89% 90-99% near occ degree of stenosis

Figure 15.6. Pooled results from European Carotid Surgery Trial (ECST), the North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Veterans Affairs (VA) studies, showing the absolute risk reduction (ARR) in stroke at 3, 5, and 8 years relative to the degree of stenosis at randomization.Note that the maximal benefit was observed in patients with 90% to 99% stenoses,whereas patients with near occlusion and distal vessel collapse or underfilling (string sign) did not benefit from CEA. (From Rothwell et al., 2003.)

risk (in fact there was an inverse relationship). can be identified by locating its first branch (the Table 15.1 also summarizes the principal results superior thyroid artery). Occasionally the bifur- from the ACST. Note that the results were very cation is rotated. The surgeon should remember similar to those of the ACAS. However, the key to mobilize the ECA branches toward the first finding from ACST was a 50% reduction in fatal assistant. or disabling stroke long term. There are a number of strategies for mobiliz- ing the bifurcation and distal ICA. Care should be taken to avoid excessive mobilization of the Carotid Endarterectomy bifurcation, as this leads to functional elonga- tion and distal ICA kinking (predisposing Operative Principles toward postoperative thrombosis) and an in- creased risk of procedural embolization. Most The carotid bifurcation is usually approached surgeons prefer to mobilize a discrete segment via a longitudinal incision based on the anterior of ICA well above the bifurcation so as to min- border of sternomastoid. The upper aspect of imize the risks of dislodging an embolus into the incision angles posteriorly to minimize the cerebral circulation. The patient is systemi- trauma to the greater auricular nerve. Any cally heparinized and the carotid arteries cross- superficial veins are ligated and divided. Dissec- clamped. If the surgeon chooses to shunt the tion continues medial to the sternomastoid to patient, the shunt is inserted now. The plaque is reveal the common facial vein. This large tribu- endarterectomized, tacking sutures inserted if tary of the internal jugular vein often overlies required, and the ECA origin cleared of plaque the carotid bifurcation and is a useful landmark. using the eversion technique. The arteriotomy The common facial vein is divided. Round- is closed either primarily or by a patch (vein/ toothed West retractors open up the space prosthetic). Flow is restored first up the ECA, between the perilaryngeal structures and the then the ICA. Having achieved hemostasis, the jugular vein. Dissection continues medial to the wound is closed with absorbable suture to re- jugular vein and the common carotid artery constitute platysma (usually over a deep suction (CCA). Careful dissection is then continued drain). Nonabsorbable suture or clips are used superiorly. The external carotid artery (ECA) to close the skin. 172

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Points for Debate Longitudinal or Transverse Incision? Despite being a relatively straightforward oper- No randomized trial data are available. Trans- ation in concept, few operations arouse so much verse wounds probably confer a better cosmetic debate regarding content. A summary of the result, but may be associated with problems principal debating points follows, which high- relating to access to the distal ICA. Longitudinal lights those of most practical concern. incisions inevitably divide more cutaneous nerves, leading to a larger area of anesthesia under the chin. The latter, however, is the Stop Antiplatelet Therapy or Not? approach of choice if there is any question of high carotid disease, especially in male patients There is no evidence that aspirin should be with short fat necks! withdrawn during the perioperative period. An emerging problem, however, is the effect of the ADP inhibitor clopidogrel on surgical hemosta- Anticipating Distal Disease? sis, particularly if the patient is receiving com- Preoperative preparation is mandatory. Nasola- bination antiplatelet therapy. Many surgeons ryngeal intubation opens the space between the have anecdotally observed that suture line ramus of the mandible and the mastoid process. bleeding is significantly increased in patients Nasolaryngeal intubation should probably not receiving chronic clopidogrel therapy. In the be undertaken in all patients, as there is a not Leicester Royal Infirmary, clopidogrel therapy insignificant risk of retronasal bleeding, which is stopped 1 week preoperatively and aspirin is can predispose to vomiting (and aspiration) in restarted. the early postoperative period. If the surgeon feels that temporomandibular subluxation may be necessary (preferable to dislocation), this Locoregional or General Anesthesia? must be anticipated in advance and maxillofa- The rationale for the use of locoregional anes- cial specialists must be involved. This procedure thesia is that the surgeon is immediately aware cannot readily be undertaken once the proce- dure has started. In the Leicester Royal of any neurological deficit during the proce- > dure. Accordingly, steps can be taken to treat Infirmary, 1200 CEAs have been performed this deficit. Advocates of general anesthesia over the last decade without recourse to tem- cite ease of operation, no patient movement, poromandibular subluxation. Surgeons unfa- and lower cerebral metabolic requirements to miliar with dissecting in the upper reaches of counter this deficit. There is no evidence that the neck should involve more experienced col- either anesthetic technique reduces operative leagues. High carotid dissections are associated morbidity or mortality. However, meta-analyses with an increased risk of operative stroke, of nonrandomized trials suggest that locore- bleeding, and cranial nerve injury. gional anesthesia may be associated with lower perioperative cardiovascular morbidity. When Should I Clamp the Internal Carotid A further large randomized trial (GALA) is Artery Early? currently underway in the U.K. Transcranial Doppler (TCD) allows the surgeon to be promptly aware of particulate emboliza- Preincision Infiltration with Local Anesthesia tion during the dissection phase of the opera- and Adrenaline? tion. One or two emboli warn of the likelihood of an unstable plaque. The dissection technique No randomized trial data are available. The is then made even more meticulous, and early rationale is to minimize troublesome skin edge clamping is not usually necessary, provided no bleeding at the beginning of the procedure. attempt is made to injudiciously dissect around Advocates need to be aware that subcutaneous the bifurcation. Continued embolization (des- and cutaneous bleeding may occur in the early pite modification in operative technique) is a postoperative period as the adrenaline effect worrisome phenomenon and merits consid- wears off. eration of early distal ICA clamping. There is 173

CAROTID ARTERY DISEASE usually more than enough time to complete the Should I Shunt? dissection safely and insert a shunt as necessary. This is an ever-enduring controversy. There is no evidence that a policy of routine shunting, Blocking the Sinus Nerve? selective shunting, or never shunting actually alters the operative risk, largely because the There is no randomized trial evidence that trials were small and poorly designed. Most sur- routine blockade of the sinus nerve with ligno- geons are either routine or selective shunters, caine significantly influences postoperative with the choice being most likely to reflect the cardiovascular morbidity. The rationale is that strategy of their trainer! sinus blockade minimizes intraoperative hypo- tension. However, this must be offset against the potential for postoperative reinnervation What Choice of Shunt? hypertension. In practice, once the ICA has The most commonly used shunts are the Javid been clamped,intraoperative hypotension is not (less flexible, tapered, requiring external retain- usually a problem. ing clamps) and the Pruitt-Inahara (softer, more flexible, smaller caliber, intraluminal Should I Ever Abandon a Procedure at retaining balloons). Alternatives include the This Stage? Brener in-line shunt. No large randomized trials have compared the effect of shunt type on clin- There are few situations warranting abandon- ical outcome. Evidence suggests that 90% of ment of the operation at this stage. The com- patients have flow rates within 10% of preclamp monest reason is cardiovascular instability levels using the Pruitt shunt. High carotid dis- (e.g., electrocardiogram evidence of myocardial sections probably benefit from using the Pruitt ischemia not controlled with simple therapy, shunt, as the Javid requires a further centimeter unstable arrhythmia). Other reasons reflect an or so of distal dissection to position the retain- unanticipated change in the risk/benefit ratios ing clamp. This can sometimes be quite difficult for the patient, that is, the benefits quoted to the to achieve in the upper reaches of the neck. patient preoperatively are now being exceeded by the potential risks as the procedure becomes ever more complex. Scenarios might include a Proximal or Distal End of the Shunt in First? hypoplastic carotid artery extending to the skull No randomized trial has addressed this issue. base (this can be evaluated by on-table angiog- Most surgeons insert the proximal (CCA) limb raphy). Controversy then relates to whether the first and flush the shunt to clear debris prior to ICA should be tied off or left alone. Most would distal insertion.Allowing the distal ICA to back- probably leave it alone and start the patient vent before carefully inserting the shunt can on warfarin postoperatively. Other examples also reduce distal embolism. No force should include unexpected high disease extension in a ever be applied during shunt insertion. Resis- patient with a unilateral asymptomatic stenosis. tance should encourage the surgeon to dissect As the annual risk of stroke was only about the carotid artery more distally to exclude an 2% in the ACAS and ACST trials (where high impacting coil. disease was specifically excluded),it may now be considered best to abandon the procedure, as the operative risks will be in excess of what was How Do I Know If the Shunt Is Working? quoted preoperatively. About 3% of shunts malfunction, usually because of impaction of the distal limb against What Dose of Heparin? the ICA wall or carotid coil. Unless some form of monitoring is used, this will go unnoticed. Most centers administer 5000 units of intra- Simple techniques include awake testing or venous heparin before clamping. There is no TCD. For those without any access to monitor- evidence that heparin doses tailored to patient ing, the surgeon using the Pruitt shunt can weight influences the balance between anti- temporarily clamp the CCA inflow and assess thrombotic and hemorrhagic risk. backflow from the circle of Willis (i.e., is the 174

VASCULAR SURGERY distal channel patent or not) by opening the red Patch or Not? tap on the T limb. This is another of the single-issue subjects that have characterized carotid surgery. Options The Shunt Is Working But I Am Still Worried include routine patching, selective patching, About Perfusion and never patching. No randomized trials have compared selective with routine patching. How- Advocates of TCD recommend trying to main- ever, a meta-analysis of the six randomized tain mean middle cerebral artery blood flow trials comparing routine patching with routine velocity of >15cm per second. This threshold primary closure showed that patching conferred broadly corresponds to that equivalent to the a three- to fourfold reduction in (1) periopera- level of brain perfusion usually associated with tive thrombosis, (2) perioperative stroke, (3) late loss of cerebral electrical activity. Note that this stroke, and (4) and late restenosis (Counsell threshold does not equate to loss of neuronal et al., 1997). Accordingly, there is little evidence function. If flow rates are considered inade- to support continuance with a policy of routine quate, check that the shunt limbs are neither never patching. impacted nor kinked. If there is no mechanical problem, the anesthetist can then carefully elevate the patient’s blood pressure pharmaco- Choice of Patch? logically, which usually raises the intracranial blood flow to acceptable levels. A meta-analysis by the Cochrane collaboration has shown that patch type does not influence outcome. There is, however, a perception that Traditional or Eversion Endarterectomy? prosthetic patches are probably more thrombo- genic than vein. A recently published random- Traditional endarterectomy involves the ized trial addressed this issue and observed removal of the plaque through a longitudinal no difference in the rates of embolization in arteriotomy extending from the CCA into the the early postoperative period. In reality, pa- ICA. The plaque is usually transected proxi- tient factors seem more likely to mediate mally and removed with cephalad dissection an increased risk of thrombosis than does the using a Watson-Cheyne dissector. The distal patch type. The Achilles heel of prosthetic end is feathered or transected. Eversion endar- patching is infection,which complicates approx- terectomy involves transecting the ICA from imately 1% of procedures. About half become the bifurcation. Everting the enclosing media/ apparent in the first few months of surgery, the adventitia then expels a tube of plaque.The CCA commonest organisms being staphylococci and is endarterectomized and the ICA reimplanted streptococci. Evidence suggests that removal of onto the bifurcation. Potential advantages of the prosthetic material with autologous recon- eversion endarterectomy include no need for struction is associated with the lowest risk of patching and the ability to shorten an elongated stroke and late reinfection. Secondary recon- ICA. However, neither technique is superior to struction with prosthetic material should be the other. avoided.

Tack the Intimal Step or Not? Should Vein Be Harvested from Ankle No randomized trial data are available, and atti- or Groin? tudes usually reflect the policy of the trainer. The NASCET observed that tacking sutures Vein patches are susceptible to rupture. This were associated with a higher perioperative risk. characteristically occurs on the 5th to 7th post- This nonrandomized comparison, however, may operative day and is more common in females simply reflect the fact that tacking sutures were and in hypertensives where the vein has been more likely to be inserted when the surgeon harvested from the ankle. Current advice, there- encountered a more complex case (e.g., difficult fore, is to use groin saphenous vein for patching to achieve a clean, tapering distal end-point in a because of its intrinsically stronger structure. thin walled vessel). Only about 15% of patients need their saphe- 175

CAROTID ARTERY DISEASE nous vein for alternative cardiovascular recon- testing identifies any neurological deficit structions in the next 5 years. (indicative of perfusion having fallen below the threshold for neuronal viability), but it requires Carotid Bypass? additional strategies (e.g., some sort of quality control) to identify what was actually causing Carotid bypasses should not be performed rou- the underlying problem. It has been the experi- tinely but are indicated if the endarterectomy ence at the Leicester Royal Infirmary that com- zone is too thin after plaque removal, if there bining a monitoring method (TCD) with quality is extensive atheroma and concomitant kink- control assessment () has been asso- ing, or if there is any question of infection. In ciated with a 60% reduction in the operative risk common with infrainguinal venous recon- over the last 10 years. structions, about 20% of carotid bypasses using saphenous vein develop a recurrent stenosis within 24 months. This is significantly higher Quality Control or Not? than that observed with traditional endarterec- Quality control assessment is a slightly different tomy and patching.Accordingly, bypass patients concept from monitoring. Its use is based on require serial duplex surveillance. the observation that the majority of operative strokes follow inadvertent technical error. Shorten the Carotid or Not? Accordingly, detection of technical error should Following endarterectomy, particularly if there (in theory) reduce the risk. Once again, no is a slightly redundant distal ICA, there is a randomized trials have evaluated completion tendency to observe functional elongation of angioscopy, angiography, or duplex ultrasound. the endarterectomy zone. Uncorrected, this may Advocates of monitoring and quality control predispose to perioperative thrombosis. Short- assessment have reported significant benefits. ening the endarterectomy zone may reduce this. However, such a policy is helpful only if the Options include transection and reanastomosis choice of technique addresses the appropriate (may be difficult in thin-walled, narrow-caliber question. Awake testing does not prevent vessels in female patients) or eversion plication. embolization during carotid dissection. Awake In the latter, stay sutures incorporating the testing remains the only “gold standard” for redundancy on either side of the artery are tied, determining who benefits from selective causing the excess arterial wall to be everted. shunting, but does not prevent a stroke due The eversion is then closed with a continuous to embolization of luminal thrombus follow- 6:0 Prolene suture. ing restoration of flow unless something like angioscopy is employed. Monitor or Not? Drain or Not? There is considerable skepticism as to whether monitoring reduces stroke risk after CEA. Surprisingly, no randomized trial has addressed Options include electroencephalogram (EEG), this issue. However, most surgeons insert a somatosensory sensory evoked potentials suction drain into the neck wound for 12 to 24 (SSEPs), TCD, near-infrared spectroscopy, hours on the basis that it probably does no jugular venous oxygen saturation, awake test- harm. There is certainly no evidence that drains ing under locoregional anesthesia, xenon blood increase the risk of prosthetic patch infection. flow measurement, subjective assessment of backflow, and stump pressure. In practice, the most commonly used techniques are awake Early Postoperative testing, TCD, and EEG. To date, no randomized Management trial has been performed to address this issue. However, for any form of monitoring to work, Establishing the Neurological Status the right questions must be asked. Electroen- cephalography and SSEP only tell the surgeon Following surgery, the patient must be carefully that perfusion has dropped below the threshold monitored for three clinical variables: neurolog- for maintaining electrical function. Awake ical status, wound stability, and blood pressure. 176

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If general anesthesia has been used during the that regular review is required as (quite often) operation, the patient should be closely ob- the hypertension is a transient phenomenon served to ensure that cerebral function remains and may require therapy only for 4 to 6 hours. intact upon awakening. The initial assessment Sustained postoperative hypertension at 3 to 5 should include the patient’s response to simple days requires assessment by a cardiovascular verbal commands and extremity movement. physician. Caution should be exercised in dis- Once the patient becomes fully alert in the charging patients before blood pressure is recovery room, a more detailed assessment adequately controlled, as these patients are including the vagus and hypoglossal nerve probably at higher risk of suffering seizures in function can be performed. the early postoperative period.

Neck Hematoma The Patient Suffers a The neck incision should be regularly moni- Neurological Deficit tored for swelling. This is usually a result of Intraoperative hematoma formation, although surprising amounts of tissue edema can accumulate within An intraoperative stroke is defined as having hours of the procedure. Despite achieving com- occurred if a neurological deficit becomes plete hemostasis and placing a closed suction apparent as the patient recovers from anesthe- drain in the wound, delayed bleeding result- sia. Usually the first sign is a prolonged delay in ing in hematoma and airway compromise can awakening. In the absence of any monitoring occur. Once an expanding hematoma is recog- modality, it should be assumed that the patient nized, the patient should be returned to the has suffered either a carotid thrombosis or operating room promptly to evacuate the embolization into the cerebral arteries, and hematoma and identify the potential bleeding the patient should be reexplored. The aim of source. If the patient develops respiratory dis- reexploration is to recognize and treat throm- tress, the neck incision should be opened at the bosis before an irreversible neurological deficit bedside to decompress the hematoma followed occurs. Delay beyond 1 hour is associated with by orotracheal intubation to establish an airway a progressively worsened outcome. The second if needed. Alternatively, it is useful to have infil- reason is to identify and correct a source of trated the neck incision with local anesthetic technical error responsible for platelet accumu- agent prior to finishing the procedure. Should lation and secondary embolization. a significant neck hematoma occur, it can be released without having to reintubate the patient. Neurological Deficit Within the First 24 Hours Focal neurological deficits occurring within the Hypertension and Hypotension first 24 hours are still usually thromboembolic. In the absence of any monitoring techniques, it Significant, sustained hypotension is not usually is again probably best to return the patient a problem following endarterectomy and tends immediately to the operating room. Intracranial to respond well to colloid replacement. Early hemorrhage is extremely rare within the first 24 postoperative hypertension is more common hours, and a CT scan is probably unnecessary and requires careful monitoring and control. unless it is done immediately on the way to the As a rule, most anesthetists prefer to maintain operating room. blood pressure within 10% of preoperative In the Leicester Royal Infirmary, we have pre- levels. There is anecdotal evidence from reports viously observed that the majority of early post- documenting outcome for carotid surgery operative neurological deficits were secondary under locoregional anesthesia that postopera- to carotid thrombosis. Subsequent research tive hypertension is less of a problem. Most showed that patients at risk of progressing to cases of early postoperative hypertension thrombosis had a 1- to 2-hour period of increas- respond to a single bolus or carefully titrated ing embolization on transcranial Doppler infusion of beta-blocker (e.g. labetalol). Note before any neurological deficit became appar- 177

CAROTID ARTERY DISEASE ent. This association has now been corroborated normal endarterectomy zones and in those who in many centers around the world. This phase have suffered embolic occlusion of the middle of sustained embolization can be arrested by cerebral artery mainstem. Note that transcranial intravenous infusion of Dextran 40 in saline, Doppler is used to detect any evidence of the dose of which has to be increased in 30% ongoing embolization and can be invaluable in of patients in order to control embolization. guiding decisions regarding reexploration. No case of stroke due to early postoperative thrombotic occlusion has been encountered fol- Neurological Deficit After 24 Hours lowing 1000 CEAs in the Leicester Unit since the protocol of 3 hours of TCD monitoring Strokes occurring after 24 hours have elapsed with selective Dextran therapy was instituted in have a greater number of potential underlying 1995. causes. In addition to thromboembolism, the The algorithm in Figure 15.7 summarizes the clinician must now consider the likelihood of current strategy in the Leicester Royal Infirmary hyperperfusion and intracranial hemorrhage. for managing a neurological deficit in the first Figure 15.8 summarizes the current Leicester 24 hours after a successful recovery from anes- protocol in this situation. The key difference thesia. Patients with hemiplegia/hemiparesis from the strategy for managing strokes within are more likely to have suffered a major vessel the first 24 hours is the importance of perform- occlusion and are probably more likely to bene- ing an emergency CT scan. Intracranial hemor- fit from reexploration. Patients with a mono- rhage complicates 1% of CEAs and carries a paresis or isolated dysphasia are highly unlikely very poor outcome, with up to 80% of patients to have suffered major vessel occlusion, and dying or suffering a major disabling stroke. there is time for more discriminating inves- There is currently very little that can be done tigation and treatment. The aim is to avoid to treat these patients, although vascular sur- unnecessary reexploration in patients with a geons may like to ask their neurosurgical

Figure 15.7. Algorithm for the investigation and management of patients at the Leicester Royal Infirmary who have suffered a neu- rological deficit within the first 24 hours of CEA, having made a normal recovery from anesthesia. CT, computed tomography; ICA, internal carotid artery; MCA, middle cerebral artery;TCD, transcranial Doppler. 178

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Figure 15.8. Algorithm for the investigation and management of patients at Leicester who have suffered a neurological deficit after 24 hours or more have elapsed after carotid endarterectomy (CEA).

colleagues whether they might ever consider Serial Surveillance and Recurrent Stenoses clot evacuation. Stroke due to hyperperfusion syndrome is In North America and in many centers in main- another poorly understood entity, and there is land Europe, follow-up carotid duplex scan- considerable controversy as to whether it would ning is considered mandatory. The underlying be better renamed the “reperfusion” syndrome. rationale is to monitor for recurrent lesions, as More recently, there has been renewed debate as well as for progressive disease of the contralat- to how much the condition is associated with eral carotid artery. Patients are recommended high flow as opposed to hypertensive encepha- to return for an initial follow-up visit approxi- lopathy or dysautoregulation. Patients at risk of mately 1 month following the operation to hyperperfusion-related stroke tend to have a ensure that adequate wound healing has taken history of severe bilateral disease and treated place.A carotid duplex scan is performed at that hypertension. Stroke is often preceded by time to evaluate the carotid reconstruction and seizure and severe hypertension. The main- to provide a new baseline for future study com- stay of management is control of seizures and parison. This is followed by a subsequent clinic careful reduction of blood pressure. Early CT visit at 6 months, at which time a repeat carotid scans often show changes consistent with an duplex scan is performed. If the duplex scan evolving ischemic infarction, but in fact this is shows satisfactory results of both carotid arter- often white matter edema. Paradoxically, a lot of ies, the patient may be seen 1 year following the white matter edema is present in the verte- the operation. A bilateral carotid duplex scan brobasilar territory. should be performed at that visit and at all future annual examinations. In the U.K., parts of northern mainland Late Postoperative Management Europe, and Scandinavia, the policy is com- pletely different. Here patients are reviewed at There is a surprisingly good transatlantic con- 4 to 6 weeks, and unless they are part of an sensus regarding many of the principal issues ongoing research program, they are discharged relating to carotid surgery. Two, however, serial with instructions to return if any new symp- noninvasive surveillance and reintervention for toms recur. The rationale underlying this recurrent stenoses, have aroused considerable approach is based on the following observa- debate. tions. First, the annual risk of stroke after suc- 179

CAROTID ARTERY DISEASE cessful endarterectomy is only about 1% to that balloon angioplasty alone was probably 2% in the operated hemisphere and 2% in the not safe. This observation was based on con- contralateral hemisphere. Second, it has been cerns that vessel recoil, intimal dissection, difficult to determine the actual risk of ipsilat- plaque dislodgment, and particulate emboli- eral stroke in patients with a recurrent stenosis, zation were now major potential problems, largely because many of the patients have despite not having been evident in the original already been subjected to a prophylactic redo overview. It was proposed that the insertion CEA. However, in Frerick’s recent overview, 10 of a stent would avoid the above problems published series documented the risk of stroke as well as reduce the rate of re-stenosis. A according to whether the patient had a recur- subsequent overview of outcomes following rent stenosis or not. Having corrected for the primary stenting revealed a 4.3% death/stroke effects of different lengths of follow-up and rate at 30 days in 2569 patients with either study size, a reanalysis of the data suggests that symptomatic or asymptomatic patients and a the incidence of ipsilateral stroke in patients re-stenosis rate of <5%. Interestingly, there is with a recurrent stenosis (>50%) is approxi- now a third-generation view that these results mately 5.5% at 3 years (i.e., only about 2% per can be improved even further with the use of annum). For those with no evidence of a re- cerebral protection devices. These devices current stenosis, the risk of ipsilateral stroke (distal balloon, distal aspiration, distal filters was 3.3% over 3 years (i.e. only about 1% per and umbrellas, and retrograde flow during annum). These figures correlate closely with the balloon insufflation) are currently under devel- follow-up data reported in the international opment or clinical evaluation. trials. Third, acute changes in plaque morphol- To date, the results from voluntary stent reg- ogy tend to precede onset of symptoms rather istries and single centers around the world have than a progressive worsening of stenosis. In clearly demonstrated that angioplasty is feasible short, if one reviews the results of the last sur- and accepted by patients. It remains to be seen veillance scan before onset of neurological when and where it should replace endarterec- symptoms, it rarely enables reliable prediction tomy. The situation regarding carotid angio- of patients at risk of subsequent stroke. plasty, therefore, is analogous to that faced by the cardiac surgeons in the 1980s when coro- nary angioplasty was first introduced. Ulti- mately, the answer will have to be determined Carotid Angioplasty by level I randomized trials, and it is inevitable that angioplasty will have a role in the manage- Angioplasty is an accepted component of ment of selected patients with cerebral vascular vascular practice apart from the cerebral cir- disease. Evidence suggests that the worst culation. The reason for this discrepancy is procedural outcomes are to be encountered in the potential for procedural embolization and older patients, symptomatic patients, those with stroke. The first carotid angioplasty was per- lesions longer than 10mm, and those with more formed in 1980. By 1992, the first overview of severe degrees of stenosis. balloon angioplasty in the carotid artery was An overview of the published literature in published. In a pooled series of 123 patients 2000 indicated that the results of angioplasty from 10 studies, the procedural mortality rate were generally poorer than surgery in trials was 0%, the disabling stroke rate 0%, and the reporting outcomes in symptomatic patients 30-day death and any stroke rate was 0.8%. who should, otherwise, form the mainstay of This study was thereafter a catalyst for the current treatment (Golledge et al., 2000).Angio- increasing interest in the potential for angio- plasty cannot simply be justified because it is plasty to replace endarterectomy as the gold effective in predominantly asymptomatic popu- standard treatment for occlusive carotid artery lations. Using the results of ACAS as a guide, disease. only 58 ipsilateral strokes would be prevented However, despite the excellent results from per 1000 on asymptomatic pa- these pioneers of angioplasty (particularly as tients with 60% to 99% stenoses. they appeared safer than diagnostic angio- Five randomized trials have now compared graphy alone), concerns thereafter were voiced CEA and angioplasty in the treatment of symp- 180

VASCULAR SURGERY tomatic patients with carotid artery disease. Future Perspectives Four have been published in peer-reviewed journals, whereas the SAPPHIRE study has only There are a number of key issues that must be recently been presented to the American Heart addressed and implemented in the next 5 years: Association. The Leicester trial was abandoned after a • Researchers must ensuring that the popu- small number of patients were recruited lation-based results are equivalent to those because of an excess risk of stroke in the angio- of the ECST and NASCET. plasty group. The WALLSTENT study was aban- • Surgeons must know and quote their own doned after 1 year, again because of a threefold results rather than those from the ECST excess risk of stroke in the angioplasty arm. The and NASCET. fourth trial was performed in a community • The aim of treatment is not simply identi- hospital in the U.S. that reported no early or fying those with operable carotid disease. late strokes at all in either arm. The largest ran- Optimal medical therapy must be imple- domized study to date is the CAVATAS. This trial mented in everybody. randomized 504 patients and found that at 1 • High-risk symptomatic and asymptom- year there was no significant difference in the atic patient subgroups must be identified rate of ipsilateral stroke relative to angioplasty to optimize clinical benefit and cost- or surgery. However, the re-stenosis rate was effectiveness. The simple fact remains that significantly higher in the angioplasty group. at 3 years, NASCET and ECST have shown The most worrisome aspect of the CAVATAS that 70% of symptomatic patients did not trial was the excessive 30-day risk of stroke or need surgery (or by inference angioplasty), death in both the CEA (9.9%) and angioplasty whereas ACAS showed that almost 90% patients (10.0%). The SAPPHIRE study ran- of asymptomatic patients did not need domized 307 patients to CEA or angioplasty. intervention. The 30-day risks of death/stroke were not significantly different (4.4% following angio- • Randomized trials, as opposed to personal plasty versus 6.1% after surgery), but the major dogma and interdisciplinary turf wars, adverse event rate (30-day risk of death/ should determine which patients will stroke/MI) was 5.8% versus 12.6% in favor of benefit from surgery or angioplasty in the angioplasty (presented at the American Heart future. Association in 2002). The inclusion of MI as a hard end-point is a new development in the history of performing randomized carotid References surgery trials. Evidence suggests that following a successful Bamford J, Sandercock P,Dennis M, Burn J,Warlow C. (1990) angioplasty, the risk of recurrent symptoms and J Neurol Neurosurg Psychiatry 53:16–22. severe re-stenosis are low. A number of centers Bonita R. (1992) Lancet 339:342–4. have documented a zero incidence of late stroke CAPRIE Steering Committee (1996) Lancet 348, 1329–39. < Collins R, MacMahon S. (1994) Br Med Bull 50:272–98. with restenosis rates of 5% at 12 months. In Counsell CE, Salinas R, Naylor R, Warlow CP. (1997) Eur J CAVATAS, the rate of re-stenosis at 12 months Vasc Endovasc Surg 13:345–54. was 14%. Golledge J, Mitchell A, Greenhalgh RM, Davies AH. (2000) In the U.K., angioplasty is generally reserved Stroke 31:1439–43. Loftus IM, Naylor AR, Bell PR, Thompson MM. (2000) Br J for use in randomized trials, although it is Surg 89:680–94. probably the optimum treatment for those few Rothwell PM, Eliasziw M, Gutnikov SA, et al. (2003) Lancet recurrent stenoses after CEA and particularly 361:107–16. carotid vein bypasses requiring reintervention. Zarins CK, Giddens DP, Bharadvaj BK, Sottiurai VS, Mabon In Europe and the U.S., the indications are prob- RF, Glagov S. (1983) Circ Res 53:502–14. ably more liberal but should remain within institutional review board control. 16 Arch Vessel, Vertebrobasilar, and Upper Extremity Eva M. Rzucidlo and A. Ross Naylor

The innominate, proximal common carotid and giant cell arteritis, and radiation-induced ather- upper limb arteries are relatively rare sites for osclerosis. Trauma is relatively uncommon, atherosclerotic disease, arteritis, and trauma. but may follow a deceleration injury in major Accordingly, there is little evidence-based liter- vehicle accidents or penetrating injury. Innom- ature to guide clinical practice. The Joint Study inate artery occlusive disease tends to occur in of Arterial Occlusion reported that the incidence patients in their fifth and sixth decades (Azakie of severe lesions demonstrated by arteriography et al., 1998). In the United States, there appears in the innominate and proximal subclavian to be a trend toward the majority being women. artery was 17%. However, of the 2000 operations Conversely, in France, Kieffer et al. (1995) performed at the University of California– reported that 72% of the 148 patients undergo- San Francisco for supra-aortic disease, only ing innominate artery reconstruction for ather- 7.5% were undertaken for innominate, common osclerosis in their practice were men. carotid, or subclavian artery lesions. Symptoms The Innominate Artery Symptoms largely depend on the underlying etiology, anatomy, and co-involvement of other Etiology major vessels. For example, in the bovine anomaly (Fig. 16.2) the innominate and left Innominate artery (IA) occlusive disease is common carotid arteries arise from a common uncommon, representing only 1.7% of all origin, and therefore any symptoms could operations performed at the University of involve either the carotid territory or the verte- California–San Francisco for occlusive lesions bral system. In general, innominate artery involving the brachiocephalic trunk, vertebral lesions present with symptoms of ischemia of arteries, and carotid bifurcation. Most contem- the right upper extremity, symptoms involving porary studies report that 61% to 84% of anterior cerebral circulation, symptoms refer- patients with innominate artery disease have able to the posterior circulation, or combined concomitant arch, vertebral, or carotid bifurca- upper extremity and neurological symptoms. tion lesions (Rhodes et al., 2000). Upper extremity symptoms occur in 5% to In the United States the most common etiol- 63% of patients and include claudication due ogy of innominate artery occlusive disease is to hemodynamic compromise or embolic phe- atherosclerotic disease (Fig. 16.1). Other impor- nomenon from unstable proximal lesions. A tant etiologies include Takayasu’s arteritis combination of upper extremity and neurolog- (second most common in the United States), ical symptoms occurs in 30% to 40% of patients.

181 182

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A B

Figure 16.1. A: Arch angiogram showing occlusion of the innominate artery and a severe stenosis at the origin of the left common carotid artery (arrow).B: Delayed films following on from part A.The right subclavian and distal innominate arteries are filled via ret- rograde flow down the right vertebral artery.The actual innominate occlusion is relatively short.

Cerebrovascular symptoms [transient ische- mic attack (TIA)/stroke] may be due to thromboembolism into the carotid circulation (hemisensory/motor signs, monocular blind- ness, or higher cortical dysfunction) or the vertebrobasilar system (bilateral sensory/motor signs, dysarthria, ataxia, nystagmus, homony- mous hemianopsia, cortical blindness, etc.). Neurovascular symptoms affect 5% to 90% of patients with severe innominate artery disease. Ten percent of patients present with global ischemia involving both the carotid and verte- bral territories.

Diagnosis Many of the clinical features of innominate artery occlusive disease are of equal relevance to subclavian and vertebral artery disease and are reviewed in this section. Atherosclerotic disease of the supra-aortic trunk is suggested by absent pulses in the neck (subclavian, carotid) or arm Figure 16.2. Bovine arch anomaly. The innominate and left (axillary, brachial) in one or both sides. Unequal common carotid arteries have a common origin (arrow).There is or abnormally low blood pressures in the upper a large atherosclerotic lesion causing a severe stenosis of the extremity should also be noted. Physical exam- bovine origin and total occlusion of the left subclavian artery. ination should include palpation and ausculta- 183

ARCH VESSEL,VERTEBROBASILAR, AND UPPER EXTREMITY tion of the proximal and midcervical carotid Treatment pulses and palpation of the superficial tem- poral, subclavian, brachial, radial, and ulnar Historically, supra-aortic trunk disease was pulses. Carotid or subclavian artery bruits or treated by direct reconstruction. In 1956 Davis thrills suggest innominate artery or other et al. first described transthoracic innominate supra-aortic trunk stenotic lesions. Absent endarterectomy. Later, in 1958, DeBakey des- pulses are suggestive of occlusions. cribed prosthetic bypass grafting of the great Blood pressure comparison of both upper vessels. In appropriately selected patients, both extremities is mandatory. If bilateral upper forms of direct reconstruction can give excellent extremity blood pressures are determined to be results. low, comparison should be made to those in the Most patients with supra-aortic trunk ather- lower extremity. The hands should be inspected osclerosis have multiple supra-aortic trunk for cyanosis, ulcers, subungual splinter hemor- lesions. Multiple arch vessel involvement occurs rhages, or livedo reticularis, which may indicate in 61% to 84% of patients. The best operative ulcerated proximal lesions predisposing to repair of this patient population having multi- atheroemboli. In patients with subclavian steal ple arch vessel lesions may therefore be directed (see later), a pulse delay may be detected in the reconstruction with bypass grafting. radial artery. Bypass grafting has an excellent technical A computed tomography scan of the brain is success rate and good early results with relief of an essential part of the workup of any patient symptoms in up to 95% of patients. Long-term with suspected atherosclerotic disease of the relief of symptoms appear equally as good, with supra-aortic vessels. About 80% of the cerebral primary patency rates of 95% being evident. cortex is clinically silent, and the finding of The two largest series were from Berguer et al. areas of infarction (in the absence of any previ- (1998) (100 consecutive patients followed over ous symptoms) may be helpful in planning 16 years) and Kieffer et al. (1995) (148 patients management strategies. followed over 20 years). Berguer et al. reported Duplex evaluation of the proximal supra- 5- and 10-year cumulative primary patency aortic vessels may not be possible because they rates of 87% and 81%, respectively. Stroke-free may be out of the scanning range of most survival rates at 5 and 10 years were 87% machines. However, an experienced sonogra- and 81%, respectively. Kieffer et al. reported a pher will warn the surgeon of damped wave- primary patency rate of 98% and 96% at 5 forms in the common carotid or subclavian and 10 years, respectively. The probability of vessels. This should alert the surgeon to the like- freedom from ipsilateral stroke was 98% and lihood of inflow disease and the need for 96% at 5 and 10 years, respectively. Life-table employing other imaging modalities. analysis and perioperative events were used to Arch arteriography remains the gold stan- calculate the probability of survival, which was dard for defining the anatomy of the lesion, 77% and 51% at 5 and 10 years, respectively. extent of disease, and probable etiology (e.g., Most patients died from cardiac events. atherosclerosis versus arteritis). A complete The excellent outcomes following bypass examination should include an arch aortogram, grafting of supra-aortic trunk disease, however, selected carotid views, vertebral imaging, and does not come without a price. Perioperative images of the intracranial circulation. mortality ranges from 0% to 15%. In the more Concomitant coronary artery disease is recent studies, the rate generally is around 5% present in 40% to 50% of patients with supra- and is mostly attributable to cardiac causes. The aortic trunk disease. Inevitably, these patients perioperative stroke rate ranges from 0% to 8% have other cardiovascular risk factors including giving a combined stroke and death rate of hypercholesterolemia, history of stroke, TIAs, almost 16%. Rhodes et al. (2000) have deter- peripheral vascular disease, hypertension, dia- mined risk factors for early and late complica- betes, and renal insufficiency. A prior history of tions in these patients. Patients with serum smoking is present in 78% to 100% of patients creatinine levels of ≥2 had a significantly higher with supra-aortic trunk disease. Accordingly, combined stroke/death rate when compared to cardiac evaluation is advisable, especially if any patients with normal creatinine (50% versus major reconstructions were planned. 7%). Similarly, stroke rates were higher in 184

VASCULAR SURGERY patients with preoperative evidence of a hyper- than 900 patients. None of the reports are ran- coagulable state (33% versus 4%). domized controlled trials (as is also the case Although there have been no randomized with surgery), and long-term results are still not controlled trials, endarterectomy has been available. reported to confer the same results as bypass A comparative trial of stenting and surgical grafting. Bypass grafting of supra-aortic trunk intervention for supra-aortic trunk lesions was lesions requires the use of prosthetic material, reported in 1998 by Whitbread et al. Eighteen often with multiple limbs, which may be kinked patients with symptomatic arch vessel stenosis after closure of the sternotomy wound. or occlusion were treated with angioplasty and Endarterectomy has the advantage of recon- stenting, and the data compared with the pub- struction without the use of prosthetic material, lished results following surgical procedures. The but is technically intimidating to surgeons who primary success rate was 100%, with no major have limited experience of operating in that part procedural complications, and at 17-month of the vascular system. It is essential, therefore, follow-up all patients were asymptomatic with that patients are selected carefully. Anatomical 100% primary patency. The incidence of stroke features considered contraindications for and death was 3% and 2%, respectively. The endarterectomy include (1) atherosclerosis or authors therefore concluded that stenting calcification of the aortic arch extending into should now be considered the first-line therapy the origin of the innominate artery, and (2) for brachiocephalic obstruction. A review of the close proximity of the origin of the left common available literature suggests that the initial carotid artery, which prevents safe clamping of success rate is higher with stenoses (98%), as the innominate artery without increasing the opposed to occlusions (46%). Both types of risk of embolization or of compromising cere- lesions were treated with minimal mortality bral blood flow. Endarterectomy would not be (0.2% for stenoses and 0% for occlusions), the an appropriate option in patients with bovine stroke rate was commendably low (0.3% for arches (Fig. 16.2) as cross-clamping would pre- stenoses, 0% with occlusion), and with no dispose to inadequate left hemisphere perfu- reports of arm embolization. Recurrence of sion. The San Francisco group has long been stenoses was similar for both stenotic lesions proponents of the endarterectomy technique and occlusions. With a mean follow-up period, and has partly overcome the problems imposed 63 months, the incidence of recurrent stenosis by multiple vessel disease by performing sepa- was identical: 11% in originally stenotic lesions, rate on each of the affected 9% for occlusions. vessels (Azakie et al., 1998). Certain diseases Although the initial results following angio- processes (inflammatory arteritis and radiation plasty of supra-aortic trunk lesions are well arteritis) are best treated with bypass grafting, documented, there is a relative lack of reports as the pathological process is a transmural describing the long-term results. There are, process and development of an endarterectomy however, reports of endovascular treatment of plane may be difficult. patients with supra-aortic trunk lesions with 9- The emergence and technical advances in and 15-year follow-up (Henry et al.,1999).These percutaneous angioplasty, however, have ren- follow-up results are longer than most pub- dered many of these major reconstructions lished surgical series. Cumulative primary obsolete. Percutaneous therapy for occlusive patency was 91% to 95% at 5 years and 81% to lesions of supra-aortic trunk disease has several 84% at 10 years. Sullivan et al. (1998) prospec- advantages over a surgical approach. These tively studied acute and long-term results of include its minimally invasive nature, avoidance angioplasty and stenting in occlusive lesions of of general anesthesia, lower cost, and, most the supra-aortic trunk. The initial technical importantly, the potential for lower morbidity success rate was 94%, and 80% of the technical and mortality. Percutaneous angioplasty for failures were due to an inability to cross occlu- treatment of supra-aortic trunk lesions was sive lesions. With initial failures included, life introduced in 1980. Since that time more than table analysis revealed 84% patency at 35 30 small series have been published regarding months. None of the patients required reinter- the role of angioplasty or stenting as primary vention or surgical conversion for recurrent therapy for supra-aortic trunk lesions in more symptoms. The authors concluded that angio- 185

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A B

Figure 16.3. A: Severe stenosis in the right subclavian artery immediately distal to the vertebral artery (arrow).This produced arm symptoms only and no subclavian steal.This was successfully treated by angioplasty (B).

plasty and stenting of the supra-aortic trunk subclavian artery disease was only found in vessels could be performed with relative safety 4.3%. Isolated subclavian artery stenosis (Fig. and satisfactory midterm success. 16.3) is most commonly found in patients with Endovascular treatment of supra-aortic systemic vascular disease. The true prevalence trunk lesions began prior to the advent of arte- of subclavian artery disease, however, is difficult rial stents. Some groups have advocated the to estimate because most patients are asympto- routine use of stents, whereas others use them matic. Only 24% of patients with disease of the only when angioplasty produces technically subclavian artery arteriography have symp- inadequate results. The routine use of stents toms. The left subclavian artery, arising directly is supported by nonrandomized evidence from the aortic arch, tends to be affected three documenting improved early and long- to four times more frequently than the right. term patency rates, especially when treating Other important causes of subclavian artery occlusions. disease include aneurysm, radiation arteritis, One further role for endovascular interven- Takayasu’s arteritis, and the thoracic outlet syn- tion is in the management of the critically ill drome. Thoracic outlet syndrome is due to com- patient with innominate disruption or false pression of one or more components of the aneurysm formation following trauma. The neurovascular bundle (subclavian artery, sub- whole procedure can be undertaken via direct clavian vein, and brachial plexus) by a cervical exposure of the right common carotid artery rib (Fig. 16.4), fibrous band, first rib, and clavi- with retrograde cannulation of the carotid and cle and anatomical anomalies of the scalene innominate arteries. musculature. The Subclavian Artery Etiology Subclavian artery lesions are relatively uncom- mon, but are encountered more frequently than innominate or proximal common carotid artery lesions. The most common cause is atheroscle- rosis. In 4748 angiograms performed for signs and symptoms of ischemic cerebrovascular disease, the prevalence of stenosis greater than 30% was 21%, whereas the prevalence of occlu- sion was 3%. Out of nearly 2000 great vessel Figure 16.4. Three-dimensional magnetic resonance tomo- reconstructions by Wylie and Effeney (1979), graphic image of cervical rib with connection on to first rib. 186

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Symptoms artery. If thereafter they should develop a severe stenosis or occlusion of the proximal subclavian As with the lower limb, symptoms can be acute artery, arm exercise can steal blood away from or chronic. Thromboembolism from a subcla- the heart. Most patients present with recurrent vian artery aneurysm can cause acute upper angina symptoms or cardiac failure. Treatment limb ischemia or more focal digital ischemia. (angioplasty or carotid subclavian bypass) pro- The latter may also originate from poststenotic duces significant improvements in blood flow to dilatation distal to (1) an atherosclerotic proxi- the heart. Clearly, cardiac surgeons should be mal subclavian stenosis or (2) a damaged artery aware of the potential for this problem and in patients with thoracic outlet syndrome. The arrange for imaging of the subclavian arteries if latter is a surgical emergency and must be rec- there is any evidence of dizziness with arm exer- ognized and treated promptly. cise, forearm claudication, unequal blood pres- Chronic symptoms depend on the location sures in the upper limbs, or weak radial pulses of the disease. Lesions distal to the origin of the on palpation. Any significant lesion can there- vertebral artery present with forearm claudica- after be treated (usually with angioplasty) or tion with exercise. No neurological signs or alternative conduits considered (contralateral symptoms are elicited from the history. Occlu- internal mammary, radial artery, saphenous sive/stenotic disease proximal to the origin of vein). the vertebral artery produces the subclavian Thoracic outlet syndrome is characterized by steal syndrome. Here forearm exercise increases symptoms attributable to compression of the the need for increased blood flow, which is pro- subclavian artery, vein, or brachial plexus. duced via reversed flow in the ipsilateral verte- Arterial compression can cause claudication bral artery. with exercise, Raynaud’s phenomenon, digital Subclavian steal is a vertebrobasilar neuro- microembolization, and even acute upper limb logic symptom that occurs with ipsilateral arm ischemia. Arterial symptoms are usually associ- exercise. With the use of the affected arm, the ated with bony anomalies (e.g., cervical rib) or demand for blood flow increases and the arm compression between the clavicle and first rib. “steals” blood from the cerebral circulation Arterial symptoms secondary to thoracic outlet through the ipsilateral vertebral artery. Interest- compression must be treated urgently. Com- ingly, even if there is reversed blood flow in the pression of the subclavian vein causes heavi- ipsilateral vertebral artery on imaging, symp- ness/blueness of the arm and can predispose to toms of vertebrobasilar insufficiency may rarely subclavian vein thrombosis (Paget-Schroetter be apparent, and the risk of posterior circula- syndrome). Venous compression/thrombosis in tion cerebral infarction is extremely low this syndrome is often seen in patients partici- (Hennerici et al., 1988) A rich collateral blood pating in demanding fitness regimes. The supply is the likely reason why symptoms may neurological component of thoracic outlet not become apparent. syndrome depends on whether there is com- Patients with atherosclerotic subclavian pression of the lower (C8/T1) or upper (C5/C6) artery disease tend to have a good prognosis, trunks of the brachial plexus. Pain or paresthe- with <20% suffering significant disease pro- sia predominate, but in severe cases muscle gression within 2 years of diagnosis. Moreover, wasting can occur. nearly one quarter of patients who presented with steal (i.e., indicating marked hemody- namic impairment) and who were then treated Diagnosis conservatively became asymptomatic over the next 42 months of follow-up (Schillinter, 2002), Duplex ultrasound is now the principal imaging indicating the potential for developing a collat- modality for examining the subclavian artery. eral circulation in this situation. Although the origin of this vessel may be A second type of steal, again peculiar to the difficult to image directly, an experienced ultra- subclavian artery, is the coronary-subclavian sonographer will be alert to a damped inflow steal syndrome. This phenomenon specifically waveform suggestive of significant disease. If occurs in patients who have had coronary required, a corroborative or diagnostic mag- revascularization using the internal mammary netic resonance angiogram (MRA) or digital 187

ARCH VESSEL,VERTEBROBASILAR, AND UPPER EXTREMITY subtraction angiography (DSA) can be artery.This is inflated while the main subclavian undertaken. lesion is angioplastied, and deflated once it is Symptoms suggestive of arterial compression completed. It is of interest to note that following (cold arm, fluctuating radial pulse with arm successful subclavian artery angioplasty, flow movements, forearm claudication, microem- reversal in the vertebral artery is not instanta- bolization) require careful x-rays of the thoracic neous. The reason for this delayed reversal of inlet to look for a cervical rib or a prominent flow is not known. transverse process on C8. The latter suggests that a fibrous band may be present. More modern tomographic imaging can demon- The Proximal Common strate the size and location of any cervical rib Carotid Artery (Fig. 16.4). Etiology Management Proximal common carotid disease occurs much Revascularization of the chronically occluded less frequently than carotid bifurcation disease, subclavian artery is possible with either angio- but 1% to 2% of patients with severe bifurcation plasty or surgery. Surgical options include (1) disease also have significant proximal common carotid-subclavian bypass, (2) carotid-axillary carotid disease. Lesions of the right common bypass, (3) axillary-axillary bypass, and (4) carotid artery are rare in the absence of innom- subclavian-carotid transposition. The choice of inate artery disease and are rarer compared to technique reflects local expertise, clinician pref- left common carotid disease. The principal erence, and patient presentation. underlying pathologies include atherosclerotic Primary patency rates following carotid- disease (most common), Takayasu’s arteritis, subclavian bypass have been reported to be and, rarely, radiation-induced atherosclerosis. 94%, with 87% symptom-free survival at 10 years (Vitti et al., 1994). The principal advantage Symptoms of subclavian transposition is that no prosthetic material is used. Here the proximal subclavian Proximal common carotid lesions present with artery is mobilized, transected, and reanasto- thromboembolic symptoms that are identical to mosed end-to-side onto the common carotid those of disease at the carotid bifurcation artery. It is reported to have similar outcomes to (hemisensory/motor signs, temporary monocu- carotid-subclavian bypass (primary patency at 5 lar blindness, higher cortical dysfunction). years, 98%; freedom from recurrent symptoms, 95%). However, these types of revascularization Diagnosis are not without risk: thoracic duct injury (2%), nerve injury (11%), stroke (6%), and wound The proximal common carotid artery is not hematoma (1%). The long-term durability of within the scanning range of current Duplex axillary-axillary bypass is inferior to carotid- technology. However, as with proximal subcla- subclavian bypass or transposition but may be vian disease, significant disease at its origin the treatment of choice in a high-risk patient causes significant damping of the waveform and because it can be performed under local anes- turbulence. If there is any evidence of this (or if thesia. For obvious reasons, this type of recon- the patient is being considered for bifurcation struction should be avoided in any patient who angioplasty), he/she will need to undergo either might subsequently a median sternotomy. MRA or DSA. Other emerging alternatives Angioplasty is the preferred option in the include computed tomography (CT) angiogra- United Kingdom and most European countries. phy. Clearly the choice reflects the unit’s experi- There is, however, no consensus as to whether ence, access, and preference. stents should be routinely used. Angioplasty of the subclavian artery carries a 2% to 3% risk of Management procedural stroke. This risk can be minimized by passing a protective balloon up the brachial In the past, proximal common carotid disease artery and up into the ipsilateral vertebral required partial sternotomy and either endar- 188

VASCULAR SURGERY terectomy or bypass off the aortic arch. Other options included carotid-carotid bypass or carotid transposition. However, this is another situation where on-table angioplasty (following exposure of the mid–common carotid artery) affords a balance between minimal risk and prevention of embolization. Venting blood into a sheath or up the external carotid artery can prevent the latter. One advantage of on-table angioplasty is that it can be combined with synchronous bifurcation endarterectomy.

The Vertebral Artery Etiology The vertebral arteries arise from the proximal subclavian arteries. The first segment extends from its origin to where it enters the transverse cervical vertebral processes. The second seg- ment is intraspinal. The third segment starts at the upper border of the transverse process of C2 and passes up to the atlanto-occipital mem- brane. The fourth segment is intradural to its confluence with the contralateral vertebral to thereafter form the basilar artery. The com- monest pathology is an atherosclerotic stenosis or occlusion of the proximal vertebral artery (Fig. 16.5). Alternative (less common) patholo- gies include fibromuscular dysplasia or dissection.

Symptoms Classical vertebral territory symptoms (verte- brobasilar symptoms) include varying com- binations of unsteadiness of gait, diplopia, bilateral motor/sensory impairment, nystag- mus, ataxia, bilateral blindness, and dysarthria. Figure 16.5. Occlusion of the proximal vertebral artery with These symptoms can be due to either thrombo- distal refilling via collaterals.The most likely pathology is throm- sis or embolism (often very difficult to tell), but bosis secondary to atherosclerotic disease. the consensus view is that the majority is prob- ably hemodynamic. Tomographic imaging can sometimes help in the difficult task of discrim- inating between the two etiologies. unless they definitely coexist with other, more There is much controversy about whether typical vertebrobasilar territory symptoms. One nonhemispheric symptoms (isolated diplopia, other myth is the concept of “nipping of the isolated dizziness, isolated vertigo, syncope, intraspinal vertebral arteries causing dizziness etc.) can be attributed to disease in the verte- on head movement.” At the Leicester Royal brobasilar system. To date, there is no com- Infirmary, a number of these patients have been pelling evidence that they are attributable examined with transcranial and extracranial 189

ARCH VESSEL,VERTEBROBASILAR, AND UPPER EXTREMITY duplex imaging, and none have ever been noted for distal control of the common carotid artery to have any change in flow or direction of flow and the ability of flushing the artery of athero- with head movements. All were subsequently sclerotic emboli. Flow through the external found to have inner ear pathologies. There is carotid artery is usually sufficient for cerebral also no evidence that coils or kinks in the prox- perfusion. If concomitant bifurcation disease imal vertebral artery are responsible for cere- is present (around 2% of patients), then the brovascular symptoms unless a coexistent common carotid lesion should be treated first. stenosis is present. Once the artery is exposed, intravenous heparin is given prior to obtaining proximal control, placement of the sheath, and crossing the lesion. Diagnosis The artery is accessed with a Potts-Cournand Duplex imaging identifies evidence of damped 18-gauge needle in a retrograde fashion and a flow, hypoplastic arteries (not uncommon), and 0.035-mm wire in advanced with the help of inflow stenoses. It is not, however, particularly fluoroscopy into the aortic arch. A 35-cm-long good at imaging the entire length of the artery. sheath may be placed to allow for more distance Accordingly, patients suspected of having verte- between the surgeon and radiation field, brobasilar insufficiency should undergo MRA decreasing exposure to the surgeon’s hands. or intraarterial DSA. Access of the femoral artery allows for place- ment of a flush catheter in the aortic arch and more precise localization of the ostium of the Treatment vessel. Selection of the innominate artery and selected oblique views to define the right The treatment of vertebral artery stenoses/ common carotid and right subclavian origin is occlusions is to first address the anterior circu- imperative for precise stent placement. The true lation. If there is significant internal carotid location of the ostium is imperative to deter- artery disease, carotid endarterectomy should mine optimal stent placement, with 1 to 2mm of be employed first. Some centers have reported the stent protruding into the lumen of the aortic huge series of vertebral reconstructions. arch. Occlusions should be predilated to avoid At Leicester (apart from carotid-subclavian stent dislodgment during crossing of the lesion bypass), only three vertebral reconstructions or to allow for safe passage of self-expanding have been performed over the last 8 years, all stents across the lesion. Whether balloon involving segment 1. Angioplasty is currently expandable stents or self-expanding stents are the emerging treatment of choice, although better is unknown, as there are no compara- some surgeons remain strong advocates of tive studies. It would seem logical that if the surgical revascularization of segment 2 (endar- lesion is tortuous or crosses the clavicle, a self- terectomy and patch, bypass, transposition onto expanding stent, which is more flexible, would the carotid artery). be preferred. Cerebral protection devices may change the need for surgical control of the common carotid artery. These devices could be Technique used for stenoses, but not for occlusive lesions. As in internal carotid artery stenting, the lesion All interventions should be undertaken in a spe- is crossed with the low-profile cerebral protec- cially equipped operating room with dedicated tion devise prior to any manipulation of the fluoroscopic/angiographic capabilities. As one lesion. This would be impossible with an occlu- of the risks for endovascular treatment of the sive lesion.Other limitations of the cerebral pro- supra-aortic trunk is distal embolization, local tection device use would be common carotid infiltrative anesthesia supplemented with intra- size, not allowing for good apposition of the venous sedation is optimal. This type of anes- device to the artery. The device, therefore, thesia allows for continuous monitoring of the would need to be placed in the internal carotid patient’s neurologic status. artery. Due to the risk of distal embolization, com- Subclavian lesion may be treated both from a mon carotid lesions are best treated through a femoral and brachial approach. Again, a com- limited surgical incision in the neck. This allows bined brachial-femoral approach allows for 190

VASCULAR SURGERY placement of a flush catheter in the aorta and References therefore more precise placement of the stent. With occlusive lesion, the brachial approach Azakie A,McElhinney DB,Higashima R,Messina LM,Stoney allows for more pushability to cross the lesion. RJ. (1998) Ann Surg 228:402–10. The caveat to this approach is risk of dissection Berguer R, Morasch MD, Kline RA. (1998) J Vasc Surg 27: into the aortic arch. In general, stenting allows 34–41; discussion 42. for tacking of the dissections. Other considera- Hennerici M, Klemm C, Rautenberg W. (1988) Neurology 38:669–73. tions are posterior circulation embolization. It Henry M,Amor M, Henry I, Ethevenot G, Tzvetanov K, Chati is therefore imperative to determine flow direc- Z. (1999) J Endovasc Surg 6:33–41. tion in the vertebral artery by duplex ultra- Kieffer E, Sabatier J, Koskas F, Bahnini A. (1995) J Vasc Surg sonography. Antegrade vertebral flow is delayed 21:326–36; discussion 336–7. from 20 to 240 seconds, serving as an effective Rhodes JM, Cherry KJ Jr, Clark RC, et al. (2000) J Vasc Surg 31:260–9. protective mechanism against embolism in the Sullivan TM,Gray BH,Bacharach JM,et al.(1998) J Vasc Surg posterior circulation. Brachial artery cutdown 28:1059–65. allows for direct repair of the artery after com- Vitti MJ, Thompson BW, Read RC, et al. (1994) J Vasc Surg pletion of the stenting, thus decreasing the 20:411–7; discussion 417–8. Whitbread T, Cleveland TJ, Beard JD, Gaines PA. (1998) Eur risk of atherosclerotic emboli (allowing for J Vasc Endovasc Surg 15:29–35. flushing of the artery) and avoiding risk Wylie EJ, Effeney DJ. (1979) Surg Clin North Am of hematoma. 59:669–80. 17 Aneurysmal Disease Philip Davey and Michael G. Wyatt

Arterial aneurysmal disease has been recog- aneurysms must not be confused. In the former, nized now for over 4000 years, with the expres- generalized dilated vasculature (>50%) is ob- sion “aneurysm” deriving from the Greek word served but, unlike the latter condition, normal- aneurysma, meaning “a widening.” Historical caliber vessel segments do not distinguish these review charts a condition in which initially conditions. observational experiences of aneurysms have Aneurysmal disease may be classified as been gradually replaced with the established follows: treatment regimes we see in clinical practice today. Advances made in aneurysm manage- 1. By nature: true aneurysms relate to a dis- ment reflect not only improved surgical acumen tinct pathological process involving all and the appliance of innovative technology but three layers of the arterial wall. False or also the progress made in our basic scientific pseudoaneurysms do not reflect a gen- knowledge, clinical experience, diagnosis, peri- uine aneurysmal process at all but rather operative care, anesthesia, and follow-up of clinical mimicry true disease. They are, in the disease. Aneurysmal disease constitutes a fact, a vessel-associated contained blood substantial component of the vascular surgeon’s collection and typically result from work load, and this chapter reviews the trauma. common pathology with reference to contem- 2. By morphology: saccular aneurysmal porary opinion in pathogenesis, diagnosis, and disease is present if only part of the vessel management. circumference is diseased. Entire circum- ferential involvement is termed fusiform. 3. By etiology: aneurysms are frequently Classification of referred to with respect to an antecedent disease process. The list, which is not Arterial Aneurysms exhaustive, includes a. Degeneration (e.g., atherosclerosis, The aneurysm is defined as an abnormal, fibromuscular dysplasia) focal dilatation of a blood vessel. An artery is empirically considered aneurysmal when its b. Infection (e.g., syphilis, bacterial, diameter becomes 50% larger than its normal fungal) vessel segment. This diagnosis is distinct from c. Trauma (e.g., iatrogenic, penetrating, ectasia, which refers to a dilated vessel that blunt) has not yet reached this threshold. Similarly, d. Inflammation (e.g., Takayasu’s or the conditions of arteriomegaly and multiple Kawasaki disease, polyarteritis nodosa)

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e. Connective tissue disorders (e.g., Chronic inflammation plays an important Marfan syndrome, Ehlers-Danlos role in aneurysmal disease. Much of the vessel syndrome) wall destruction is undoubtedly mediated by the f. Congenital (e.g., tuberous sclerosis, inflammatory infiltrate composed of T cells, Turner syndrome) macrophages, B lymphocytes, and plasma cells, 4. By location: for example,abdominal aortic, but the antecedent trigger for this cellular popliteal, femoral, subclavian, thoracoab- migration remains unclear. It has been sug- dominal, etc. gested that aneurysmal disease is in fact an antigen-driven immune disease from work analyzing AAA disease. Proposed antigenic Pathogenesis of activators to subsequent inflammation include elastin, interstitial collagen, oxidized low- Aneurysmal Disease density lipoprotein, cytomegalovirus, and artery-specific antigenic proteins such as Despite extensive research, the exact mecha- AAAP-40. Following T-cell antigen recognition, nisms underlying aneurysm pathogenesis the inflammatory cascade begins, ultimately remain unclear. It appears the process is multi- resulting in vessel wall degradation and pro- factorial, involving variable components of gression to aneurysmal disease. altered biochemistry, immunological, mechani- Arterial wall biomechanical stress is also cal,and genetic importance (Wassef et al.,2001). accepted as being of considerable importance Much of our understanding of the disease in both aneurysm progression and rupture. relates to work performed on the abdominal Model analysis of wall stress variation in differ- aorta, and it is assumed that nonaortic aneurys- ent anatomical locations implies that altered mal disease results from a similar pathological hemodynamic profiles may explain the varying sequence of events. susceptibility of an arterial wall to become Aneurysmal disease ultimately results follow- aneurysmal (e.g., increased disease incidence ing gradual proteolytic degradation of arterial in abdominal as opposed to thoracic aorta). vessel walls. Structural integrity of arterial wall It is suggested that mechanical failure from is dependent on adequate functional connective excessive stress initiates and promotes ane- tissue elements including elastin and collagen. urysmal pathogenesis first by the aggregation Loss of these elements weakens the vessel wall of humoral factors, and then by a consequent and thus predisposes to aneurysm formation. focal inflammatory response and finally wall Research into abdominal aortic aneurysms breakdown. (AAAs) has discovered local increased levels of The familial clustering of aneurysmal matrix metalloproteinases (MMPs) that result in disease has led to interest in determining a this observed connective tissue breakdown. possible genetic explanation for the process. Four MMP subtypes are thought to be of impor- Supporting evidence is derived from observa- tance in this process: gelatinases (MMP-2 and tions regarding the altered disease charac- MMP-9), matrilysin (MMP-7), and macrophage teristics of “familial” and “spontaneous” elastase (MMP-12). In addition to this increased aortic aneurysmal disease. Cases of familial local expression, altered levels of circulating AAA present significantly younger, carry a proteases may play a role, and research con- greater rupture risk (especially in females) tinues into the contributions to aneurysmal and are 18 times more likely to be present in disease from various plasminogen activators, other family members than is seen with sponta- serine elastases, and cysteine proteases (cathep- neous pathology. Affected sibling pair DNA sins S and K). Abnormally low levels of protease linkage studies aims to identify the putative inhibitors are suggested to exert the same path- AAA-susceptibility gene, whose expression or ogenic effects, and this has also been the focus mutation promotes progression to aneurysmal of much recent work. Preliminary research into disease. This approach to pathogenesis may the most abundant serine protease inhibitor, eventually form the basis of genetic testing cystatin c, has confirmed that in patients with of specific increased-risk populations, aneurysmal disease corresponding levels of this allowing more focused surveillance and early protein are indeed lower than normal. intervention. 193

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Abdominal Aortic Aneurysms seen if the definition of AAA is relaxed to even 1mm less than stated earlier (30mm), but little In the 16th century the anatomist Vesalius first difference exists between the two methods of recognized aneurysmal disease affecting the prevalence estimation in this condition. infrarenal aorta. Limited progress was made The incidence of asymptomatic AAA has over the following centuries in the treatment of been reported at 3 to 117 per 100,000 person- AAA, and it was not until 1952 that Dubost years. These estimations are derived from the reported the first successful treatment of the number of hospital admissions for elective condition by surgical repair. In the past 50 years, asymptomatic AAA repair and have been increased experience and advancement of sur- observed to increase by 7% to 26% over the past gical techniques have rendered elective AAA 15 years. This basically reflects changes in repair a routine albeit major operative proce- improved disease awareness, referral patterns, dure with expected mortality rates of less than and diagnosis, more specifically the increased 5% (Hallin et al., 2001). Exciting developments availability and use of ultrasound scanning in in the endovascular arena over the last decade recent years. The reported incidence of rup- have offered further options for treatment in tured AAA is much more inaccurate due to high elective AAA disease and promises to revolu- prehospital mortality, but quoted values are tionize management for many patients. between 1 and 21 per 100–000 person-years. The natural history of AAA is to gradually Data also suggests that this value is continuing expand and eventually rupture. Ultimately, the to increase by 2.4% per year. In the United aim of elective surgery is to prevent this from Kingdom, ruptured aortic aneurysms have been happening by excluding the aneurysm from the reported as the 13th commonest cause of death circulation by means of either prosthetic graft accounting for 1.2% of male and 0.6% of female insertion or endovascular stent deployment. mortality. Unfortunately, even with improved periopera- Abdominal aortic aneurysm is typically a tive management and operative technique, the disease of the male population, being five times great advances made in elective AAA repair more common than in women. A sharp have not been witnessed in the emergency increased incidence is seen after the age of 50 setting for AAA rupture, and consequently mor- years, rising to a peak at 80 years of age.Abdom- tality rates remain high at approximately 50%. inal aortic aneurysm in females does not tend to occur until about 10 years later than in men, and then increases linearly from the age of 60. Definition In a more general sense, 5% of the over-60 population will have an AAA, and at the age of Aneurysms are arbitrarily defined as a segment 67 a man is ten times more likely to die from a of vessel dilatation that is at least 50% larger ruptured AAA than is a woman. than the expected normal vessel diameter. In practical terms this diameter refers to the nona- neurysmal adjacent vessel segment. We accept a Risk Factors for Abdominal “normal” abdominal aorta to be approximately 20mm in diameter, and therefore an aorta wider Aortic Aneurysm than 30mm would suggest aneurysmal disease. Factors associated with an increased risk of aneurysmal development in the infrarenal aorta Epidemiology include increasing age, male sex, ethnic origin, family history, smoking, hypercholesterolemia, In all epidemiological analysis, statistical varia- hypertension, and prior vascular disease. tion can exist as a result of inconsistent Studies suggest that of these, male sex and definitions of disease, and AAA is no exception. smoking are the most important, increasing Population screening surveys and postmortem the chances of AAA development by 4.5 and 5.5 studies have been used to estimate a current times, respectively. A positive family history prevalence of AAA of between 1.3% and 12.7% (first-degree relative affected) alone doubles the in England (Wilmink and Quick, 1998). Marked risk of AAA presentation and is more likely if increases in the prevalence of the disease are the affected relative is a female. Interestingly, 194

VASCULAR SURGERY diabetes mellitus, which is a major risk factor tive finding at laparotomy is that of massive for occlusive arterial disease, is associated with venous hemorrhage requiring rapid control to less risk (compared to nondiabetics) in the avert on-table death due to exsanguination. development of aortic aneurysmal disease. Detection of an AAA can potentially be made by careful abdominal palpation during clinical Clinical Features examination. The reliability of this technique alone is questionable, its sensitivity governed by The vast majority of AAAs are asymptomatic, a variety of factors such as aneurysm size,exam- and the diagnosis is usually made on clinical iner’s skill, patient’s body habitus, and the abdominal examination or following ultra- purpose of the clinical examination itself. Even sound investigation for other pathology. If after acknowledgment of these variables, a symptoms are present, they usually relate to correct diagnosis is achieved in only approxi- the complications of infra-aortic aneurysmal mately 50% of cases. Smaller aneurysms and disease both locally and systemically. obesity increase the likelihood of a missed Abdominal or back pain may be experienced, diagnosis,whereas an false-positive diagnosis of and this must alert the clinician to the possibil- AAA may be made in thin patients, tortuous ity of posterior erosion of the aneurysm into the , or in those with more prominent vessels neighboring vertebral bodies. Classically in this as a consequence of lumbar lordosis. Similarly, situation, the history of pain follows a non- the success of manual examination in the specific and indolent course.Appropriate subse- assessment of aneurysm size and proximal quent investigations should distinguish erosion extent in relation to the renal arteries is poor. from the diagnosis of inflammatory AAA (see Subcutaneous fat and overlying intestine tend to later). Sudden onset of severe abdominal or cause an overestimation of size, and the ability back pain in a patient with a known AAA to admit an examining hand between the costal who is hemodynamically unstable suggests margin and pulsatile mass will not indicate aneurysm rupture. The pain may radiate into infrarenal disease in all cases. the hips, and the patient will be pale, anxious, clammy, tachycardic, and hypotensive. An aneurysm rupture that is contained within the Investigations for Abdominal retroperitoneum is often seen with a similar but Aortic Aneurysm less pronounced symptom profile, affording more time for preoperative optimization than Plain Film Radiography uncontained ruptures. Plain abdominal x-rays are cheap and widely Symptoms of distal ischemia may result available but of little use in the routine diagno- directly from the presence of AAAs. Emboliza- sis of the AAA. Occasionally, calcification may tion of contents from the aneurysmal sac may be observed in the wall of the aneurysmal vessel present with acute or chronic limb ischemia, or there may be loss of the psoas major shadow. whereas a similar picture may be witnessed if In the preoperative setting their use is limited the AAA thromboses in situ. In the latter case to exclusion of an alternate diagnosis to AAA. one would expect symptoms of bilateral leg They do, however, play an important role fol- ischemia. lowing endovascular stent graft repair of AAA Less common presentations of infra-renal for observation of long-term outcome and graft aortic aneurysmal disease relate to fistulation. integrity. Cases of aortoduodenal fistulas present classi- cally with intermittent, unexplained gastroin- testinal bleeding and melena or massive Ultrasonography uncontrollable hematemesis. The diagnosis is confirmed by upper gastrointestinal endoscopy Abdominal ultrasound examination is responsi- prompting urgent surgical repair. Isolated aor- ble for the detection of the majority of asymp- tocaval fistulas are rare but present with symp- tomatic AAAs and it is also used to confirm toms of high output cardiac failure. More the suspected clinical diagnosis (Fig. 17.1). In commonly, an aortocaval fistula results as a con- addition, this modality is employed to observe sequence of aneurysm rupture, and the opera- aneurysmal expansion in patients with disease 195

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endoluminal stent grafting. The imaging, however, is invasive, time-consuming, and expensive, and it entails substantial radiation exposure for the patient.It is therefore restricted for preoperative assessment in those suspected to be imminent candidates for surgical repair, follow-up of endovascular stent graft repairs, and for patients with suspected AAA rupture who are stable enough for deferment of laparotomy. The advent of spiral CT scanning in some centers has led to increased speed of assess- ment (a single breath hold) with the ability to Figure 17.1. An abdominal ultrasound showing an aortic reconstruct CT images in a three-dimensional aneurysm. manner, resulting in a more user-friendly and informative imaging. The use of CT scanning must be judicious in patients with a prior history of contrast reaction, high blood pres- under surveillance. Ultrasound is cheap, rela- sure, and preexisting renal impairment. As with tively quick, widely available, and noninvasive. ultrasound, CT scanning cannot detect visceral Visualization of the aorta is achieved in 97% artery involvement or the presence of renal of patients, and current figures demonstrate artery stenosis, and this must be remembered in minimal interobserver variability. The avail- assessment of the generated images. ability of mobile ultrasound machines allows assessment of the critically ill patient who Magnetic Resonance Imaging ideally should not be transferred to the radiol- ogy department. Magnetic resonance imaging (MRI) for AAA Ultrasound, however, does have its limita- offers comparable results to CT scanning in tions. Unfortunately, cases of suprarenal, vis- terms of assessment of aneurysm size, proximal ceral artery aneurysmal disease and iliac vessel extent, iliac extension, and etiology (e.g., extension cannot be accurately assessed by inflammatory), and has the added advantage of ultrasound. In obese, ventilated patients, or being noninvasive and safe because no contrast those patients with excessive bowel gas, this administration is required. The procedure, unreliability is further exaggerated. Further- however, is not well tolerated by claustrophobic more, this modality is poor at confirming the patients, and its limited availability and expense presence of aneurysm rupture and hence plays have relegated its use to a second-line investi- no role in the emergency setting. gation for AAA, reserved for those patients for whom CT scanning is inappropriate (e.g., Computed Tomography Scanning iodinated contrast allergy, chronic renal failure, or claustrophobia). Computed tomography (CT) scanning remains the investigation of choice for the most accurate Angiography assessment of AAA disease. The procedure allows visualization of the upper extent of the Contrast arteriography offers little information aneurysm and its nature (i.e., noninflammatory regarding the possible diagnosis or sizing of an or inflammatory), and provides reliable infor- AAA, as it is only the vessel lumen (not the mation regarding iliac artery involvement. aneurysmal sac) that is delineated in this exam- Interobserver variation in the measurement of ination. For these reasons, this investigation aneurysm size is superior to ultrasound, with plays little role in the management of the over 90% of studies exhibiting a discrepancy routine infrarenal AAA. It does, however, offer of less than 5mm. Computed tomography detailed information with respect to possible scanning with 3-mm cuts can also be used to visceral or renal artery disease, and allows ade- determine if the patient is a candidate for quate vessel anatomy analysis for planning prior 196

VASCULAR SURGERY to surgical repair. Indications for arteriography, adequate numbers of patients with the power therefore, include aneurysms with possible to demonstrate the cost-effectiveness of this suprarenal involvement or suspected visceral approach to AAA disease. artery disease, renal stenosis, and in patients with coexistent peripheral vascular or nonaor- tic aneurysmal disease (e.g., popliteal). Again, Management of the Elective the investigation is invasive, involves the use of Abdominal Aortic Aneurysm substantial amounts of contrast agent, and carries with it the risks of embolic and renal The basic goal underpinning the management complications. of the asymptomatic and symptomatic non- ruptured AAA is to avert the presentation of Screening for Abdominal aneurysm rupture.As with all surgery,a surgeon Aortic Aneurysm must balance the risks of the required major operation in terms of mortality and morbidity There is currently much debate about the merits against that of a possible rupture-related death about introducing a national screening program with nonoperative “conservative” management. for the detection of aneurysmal disease affect- With appropriate case selection and surgical ing the abdominal aorta (Table 17.1). The nature expertise, mortality following elective AAA of AAA is such that the majority of patients have repair should be between 2% and 5%.Important the condition silently, until they present at the issues to be taken into account, which enable the hospital under the most extreme circumstances: surgeon to make the correct decision whether or aneurysm rupture. Because the prevalence of not to operate, are discussed in the following this disease is relatively high (5% of the over-60 subsections. population), it has been suggested that a simple ultrasound-screening test at about this age would uncover the asymptomatic pathology at Aneurysmal Size an early stage. Appropriate follow-up and elec- The maximum diameter of AAA is without tive repair could then be planned, thus dimin- doubt the most important factor in predicting ishing the frequency of ruptured aneurysm the ruptured risk of an aneurysm. The 5-year presentation and its inherent cost implications. rupture risk of an aneurysm less than 4cm in Recent studies in the U.K. have shown that a diameter is approximately 15%, and this rises to screening program would indeed fulfill these nearly 95% if the aneurysm grows to 7cm in expectations, observing a reduction in the AAA diameter. Unfortunately, vascular surgery is not rupture rate by 50%. Other groups suggest a an exact science, however, and small aneurysms screening program would have a greater diag- will continue to rupture and many people with nostic yield and hence prove more cost-effective large aneurysms will outlive the disease and die if only the specific, high-risk populations were of an unrelated cause. targeted, such as elderly male smokers. What- The recently completed U.K. small aneurysm ever the proposal, it would certainly appear that trial aimed to provide guidelines regarding a timely ultrasound examination may be when to offer elective surgery on the basis of beneficial in the early management of AAA, but aneurysm size (Lancet, 1998). Comparison of a large multicenter trial is needed to obtain surgical repair of small aneurysms (4 to 5.5cm) with nonoperative ultrasound surveillance sug- gested that there was no survival benefit to be Table 17.1. Why screen for aneurysms? gained from operative management of the AAA. Abdominal aortic aneurysms (AAA) are asymptomatic The trial researchers recommended that Major complication of AAA is rupture aneurysms should be considered for surgical Morbidity and mortality of repair of ruptured AAAs: repair when the maximal diameter exceeded 50% to 70%; elective AAAs, 1% to 5% 5.5cm or the aneurysm became symptomatic or Patients who survive repair have a similar life tender. It was at this stage the operative risk of expectancy as the general population Ultrasound is inexpensive and noninvasive repair was less than the risk of rupture associ- ated with nonoperative management. 197

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Treatment protocols for small aneurysms groups suggest that since propranolol blocks remain less clear-cut, but as a general rule all circulating tissue plasminogen activator (tPA), AAAs greater than 30mm in diameter should be there is a direct effect on the aortic wall by kept under ultrasound surveillance. Aortas less diminished plasmin-mediated MMP activation than 40mm in diameter should probably be and therefore reduced expansion rate.Whatever monitored with annual ultrasound scans, the pharmacological explanation, it would cer- whereas if there is growth to between 40 and 55 tainly appear that unless contraindicated (e.g., mm the frequency of observations should asthma,severe cardiac failure),a good argument increase to every 6 months. Other measures in can be made for the administration of propra- management include encouragement to stop nolol while the aneurysm is under surveillance. smoking, aggressive blood pressure control, and possibly the administration of propranolol Proximal Extent of Abdominal unless contraindicated (see later). If an aneurysm under surveillance appears greater Aortic Aneurysm than 50mm in diameter, a CT scan should be The relationship of the aneurysm to both the obtained to formally size and delineate aneurys- renal and visceral arteries must be elicited prior mal anatomy in preparation for operative repair. to surgical repair. Juxtarenal aneurysms com- At some centers,it is at this stage that the patient mence immediately below the renal arteries may be considered for endovascular treatment and thus do not permit a clamp to be placed as opposed to open repair of their aneurysm. infrarenally, as is also the case with suprarenal aneurysms, which may or may not involve the Expansion Rate superior mesenteric artery or coeliac axis. If the pathology commences higher than the coeliac Aneurysmal expansion rate is considered an trunk, the aneurysm is deemed to be thora- important factor as it enables the clinician to coabdominal. Repair of all these aneurysms estimate the timing of elective surgery governed carries significantly increased patient mortality by the size of the AAA. Much evidence suggests or morbidity with requirement for higher levels that the larger the aneurysm, the quicker the of surgical expertise. Hence, referral to a terti- expansion rate, so that aneurysmal growth ary vascular center is mandatory and repair can be considered as exponential function of should not be attempted at a district general aneurysm size. Small aneurysms between 40 hospital. and 60mm are expected to expand “normally” at an annual rate of around 10% (4 to 5mm). Patient Comorbidity Growth patterns that exceed this reflect unpre- dictable pathology and may warrant earlier sur- Full patient assessment prior to proposed AAA gical intervention. It is generally accepted that if surgery should aim to identify medical factors the aneurysm expansion rate is greater than 10 to be addressed in the preoperative workup. mm, this is an indication for operative repair, Aneurysmal surgery is obviously not appropri- regardless of the aneurysm size. ate in those patients with widespread advanced The exact reasons for the vast differences wit- malignancy and limited life expectancy or those nessed in aneurysm expansion remain unclear. with neurological degenerative disease. Other Studies have shown that smoking, advancing conditions that do not preclude surgery should age, cardiac disease, and hypertension are all be appropriately treated in order to optimize the independent predictors of an increased expan- patient for the operating room and so minimize sion rate, and that administration of certain the risks of aneurysm repair. Specific preopera- beta-blocker drugs may reduce this phenome- tive conditions associated with poor outcome non. Recently, much interest has been directed following elective AAA surgery include renal toward the medical management of small dysfunction, cardiac failure, myocardial aneurysms with the drug propranolol, which is ischemia, and respiratory impairment. The observed to reduce the rapid expansion of AAA presence of one or more of these conditions may by nearly 40%. The exact mechanism of this indicate the need for extensive preoperative finding could simply be explained by improved investigation and appropriate referral to other blood pressure or heart rate control, but some medical specialties. 198

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Individual Surgeon’s Audited Results not only physical status but mental and social aspects also. Operation for AAA should both In the current climate of clinical governance prolong and preserve quality of life. Due to the and accountability, it is no surprise that the nature of the disease, it is unlikely that AAA decision to operate in AAA does not entirely repair will lead to any physical improvement in depend on the patient but also on the ability of the preoperative condition with the risk of a the operating surgeons themselves. Advances in drastic deterioration in health. On the other operative technique and vascular anesthesia in hand, for many, quality of life is still vastly major centers have been reflected in a fall of improved by elimination of the cause of much operative mortality following elective AAA psychological torment that was the “time bomb” repair to around 2% to 5%. Unfortunately, the ticking in their abdomen. There is little doubt death rate at some district general hospitals that issues pertaining to a subject’s quality of life after the same operation by personnel without can raise difficult and emotive questions. The specialist knowledge has been reported in astute clinician should enlist help with manage- excess of 10% and poses the question of whether ment decisions from not only the patient but this surgeon-specific discrepancy warrants the also the family, nursing staff, and caregivers. shift of all elective AAA repairs to be performed Basic laboratory investigations to be per- at recognized major vascular centers. formed on all patients considered for AAA surgery include a full blood count, erythrocyte Aneurysmal Symptomatology sedimentation rate (ESR), blood glucose, serum urea, and electrolytes. Hematological disorders Symptomatic and suspected ruptured aortic and anemia may well be uncovered at this stage, aneurysms are usually in themselves an indica- prompting further investigation before surgery. tion for surgical intervention. The rationale for An elevated ESR might be the only indicator of this decision is explained by the high mortality an inflammatory AAA or even reflect ongoing rate of a presumed imminent rupture, and pre- chronic infection or inflammation elsewhere. dicted morbidity following embolism from the Hyperglycemia may expose the unknown dia- aneurysmal sac. betic and has implications for both peri- and postoperative patient care. Silent renal or Preoperative Assessment of the endocrine dysfunction is suggested with abnor- Elective Abdominal Aortic Aneurysm mal urea and electrolyte values, and these would necessitate further investigation and optimiza- One of the cornerstones of the successful man- tion before surgery. agement of the elective AAA is adequate preop- In addition to these tests a 12-lead electro- erative preparation.An extensive patient history cardiogram (ECG), chest x-ray, arterial blood and full examination should be performed, gas analysis, and pulmonary function tests followed by a set of basic investigations for all should be performed. These reflect the impor- patients. These measures should aid the deci- tance of adequate cardiorespiratory reserve sion of whether or not operative intervention on the successful outcome of AAA surgery. is appropriate and may uncover any subclinical Depending on the results obtained, it may well pathologies that can be corrected, or at least be the case that further investigations such as an optimized prior to surgery. We consider the exercise ECG, echocardiography, and even coro- required analysis as of two distinct types, exam- nary angiography should be performed before ining both general health status with quality of surgery. The presence of significant cardiac life and also aneurysm-specific factors. disease may indeed require significant inter- vention such as angioplasty, stenting, or even General Health Status bypass grafting before the patient is considered fit enough elective AAA repair. After initial assessment of an apparently med- ically fit patient, it is essential to gain an appre- Aneurysm–Specific Factors ciation of that person’s quality of life. This loose term is difficult to define but encapsulates all It is most likely that by this stage an ultrasound aspects of the patient’s daily living, involving scan will have been performed confirming the 199

ANEURYSMAL DISEASE presence of an AAA. Unless contraindicated, the by endotracheal intubation so that artificial ven- aneurysm should now be imaged by means of tilation can commence. Once the vascular anes- CT scanning for accurate sizing, proximal and thetist is satisfied, the stable patient is then distal extension, relationships to other abdomi- transferred into the main operating room. nal vasculature, and possibly an assessment for Elective AAA repair may proceed by either a endovascular stenting. In those patients where transabdominal or retroperitoneal approach as CT scanning is not an option, MRI offers an long as adequate exposure to gain proximal and alternative method of gaining the required pre- distal control is achieved. The patient is thus operative information. appropriately positioned, draped, and prepped. In the majority of cases, this constitutes all A relative indication for retroperitoneal access that is required radiologically to appropriate is the case of a “hostile” abdomen either due to plan operative intervention. However, in adhesions from a previous laparotomy or the juxtarenal or suprarenal aneurysms, or patients presence of an abdominal wall stoma. In the with peripheral vascular disease or aneurysmal majority of elective repairs, however, it is a stan- disease elsewhere, angiography should be dard transperitoneal approach that is preferred. considered. Laparotomy is performed by standard full- length midline incision offering a generous Operative Management exposure, although some surgeons advocate a transverse incision in cases with no iliac of the Elective Abdominal aneurysmal involvement. Advantages of the Aortic Aneurysm latter are a better cosmesis and a decreased inci- dence of respiratory complications postopera- Assuming the patient workup is completed and tively as a result of reduced wound pain. the patient is suitably optimized, elective AAA Long-term wound disorders, however, are seen repair can now be attempted. Broadly speaking, more frequently with a transverse incision. there are two techniques used for aneurysm Following skin incision the peritoneum is repair, and consideration will be given to each divided from a point just left to the base of the in turn. small bowel mesentery extending distally as far as the iliac artery. A self-retaining retractor is Open Repair of Elective Abdominal then positioned so that the surgeon has ade- Aortic Aneurysm quate exposure of the aneurysm, with the small bowel usually “stored” in a sterile bag for pro- It is now over half a century since the first tection and facilitation of access.The neck of the reported successful open repair of an AAA, and aneurysm is dissected free followed by each of the technique remains well established today. the iliac arteries prior to application of vascular Informed patient consent for the procedure is clamps. Intravenous heparin is given just before obtained and adequate (8 to 10 units) type- aortic cross-clamping in order to reduce the risk specific blood is cross-matched before surgery. of thrombotic complications, and this dose may Invasive monitoring is mandatory in AAA be repeated in prolonged procedures. repair, requiring insertion of a urinary catheter After allowing enough time for systemic anti- and also arterial and central venous cannula- coagulation, the clamps are applied in a manner tion. A nasogastric tube is inserted for stomach so that the possibility of distal complications are decompression, and the anesthetist may decide minimized. In practice this requires clamping of to float a pulmonary artery catheter (Swan- the least-diseased vessels first, taking care to Ganz) in those patients with significant cardiac avoid vessel damage and mural plaque disrup- disease. It is at this stage that an epidural tion. The proximal clamp should be as close to catheter may be inserted to minimize postoper- the renal arteries as possible so that the resid- ative pain. A single bolus dose of a wide- ual native infrarenal aortic segment is minimal, spectrum antibiotic (e.g., cefuroxime 1.5g) is therefore limiting the risk of subsequent usually given to reduce the risk of prosthetic aneurysmal recurrence. Once proximal and graft infection and this dose may be repeated in distal control has been achieved, the sac of the long operative procedures. The general anes- aneurysm is incised longitudinally along its thetic is administered and the airway is secured anterior surface, taking care not to damage the 200

VASCULAR SURGERY inferior mesenteric artery (IMA) that arises just sion”) as a result of rapid volume redistribution to the left of midline from the aorta. Problem- into the large dilated distal ischemic vascular atic bleeding may be encountered at this stage beds. This phenomenon is further exaggerated from patent lumbar arteries, and these are over- by systemic release of accumulated vasoactive sewn by vascular sutures. Back-bleeding from metabolites from the clamped limb, and there- the IMA should be temporarily controlled with fore timely intravenous fluid “loading” is neces- a small vascular clamp (e.g., bulldog clamp) sary following surgical alert before clamp during aneurysm repair, and the need for pos- release. sible reimplantation should be assessed later in With the graft in situ and hemostasis the operation. ensured, attention returns to the IMA. In the An appraisal can now be made regarding the majority of cases the IMA may be simply ligated type of graft to be used and appropriate sizing with a vascular suture. This practice, however, performed. In 60% of cases a straight “tube” requires at least one patent internal iliac artery, synthetic inlay graft may be used, requiring a disease-free superior mesenteric artery, pink aorto-aortic anastomosis. The remainder of healthy large bowel, and finally good back- cases require a bifurcated graft due to either bleeding on release of the bulldog clamp. If iliac extension of aneurysmal disease or con- these criteria are not met or colonic perfusion comitant occlusive pathology. In this situation appears suboptimal at the end of the procedure, the distal anastomosis should be performed into the IMA may have to be reimplanted into the a normal vessel,distal to the affected artery.This graft by means of a Carrel patch. usually requires iliac anastomosis, but if there Assuming IMA reimplantation is not neces- is extensive iliac artery disease or technical sary, the native aneurysm sac is closed over the difficulties, a femoral anastomosis must be con- graft and loosely sutured, providing physical sidered. It should be remembered in the latter graft protection from other intraabdominal scenario that the patient will be at an increased structures. The bowel is released from the tem- risk of infection and false aneurysm formation porary storage bag and a final examination is as a result of opening the groin. The graft is made to ensure adequate organ perfusion and sutured with 2–0 or 3–0 nonabsorbable stitches, also to allow correction of any iatrogenic injury. ensuring to take deep-enough bites in the prox- The patient’s limbs are also assessed to ensure imal anastomosis for adequate strength.In cases adequate distal perfusion and exclude immedi- of friable aortic tissue, the surgeon may wish to ate graft thrombosis or embolism that would consider the use of pledgets in the suture line in require prompt surgical correction. The self- order to reinforce the anastomosis. Integrity retaining retractor is removed and the abdomen of the proximal anastomosis is confirmed by closed in routine fashion. careful release of the proximal clamp against Following the operation the patient should be resistance offered by prior application of a transferred to an intensive care or high depend- clamp across the graft. Minimal bleeding sug- ency unit for close monitoring. Return to the gests successful anastomosis, and the proximal ward is usually possible the following day if clamp is reapplied to its original position so there have been no complications. that attention can now be given to the run-off Discharge following elective AAA repair is vessel(s). variable but can be expected at between 7 and Distal anastomosis should be to the appro- 14 days depending on preoperative comorbidity, priate vessel as outlined earlier, with the aim to operative difficulty, patient determination, and preserve at least internal iliac artery for mainte- postoperative complications. nance for colonic and neural blood supply.After completion of the first iliac (or distal aortic) anastomosis, blood flow into the supplied limb Complications Following Open should be restored after confirmation of anas- Abdominal Aortic Aneurysm Repair tomotic integrity. Close lesion with the anes- thetic team is required at this stage, and release Despite extensive preoperative workup and of the distal clamp should be very gradual. improvements in anesthesia and surgical tech- Sudden clamp release could lead to precipitous nique, complications following elective open falls in blood pressure (“declamping hypoten- repair of AAA still occur. All possible measures 201

ANEURYSMAL DISEASE must be taken to minimize them, as often mor- Renal bidity following aneurysm repair can translate to mortality.An acceptable mortality rate of less Impaired renal function post open AAA repair than 5% justifies prophylactic AAA repair in accounts for 5% to 12% of all early complica- appropriate aneurysms as compared to the risk tions, and of these nearly half require renal of rupture and subsequent near-100% mortality replacement therapy with dialysis. These figures with a conservative approach. The nonfatal reflect a substantial decrease in the incidence complications are considered as early or late. of renal morbidity and are attributed to the improvements made in its pre- and periopera- tive management. Advancing knowledge and Early Complications understanding of radiological contrast-induced nephrotoxicity has led surgeons to defer surgery Cardiorespiratory following such investigations in order to allow Cardiorespiratory complications account for renal recovery. Current perioperative fluid 25% to 30% of all morbidity following elective management regimes that are guided by sensi- open AAA repair. The majority of cardiac tive invasive indicators of circulating volume ischemic events take place in the initial 48 hours (e.g., Central Venous Pressure (CVP) lines) have postoperatively, myocardial infarcts accounting also improved the perioperative maintenance of for a third of these. Measures that can be taken a normal cardiac output and renal blood flow. by the surgical team to reduce the incidence of The exact cause of renal failure despite these these complications include appropriate fluid measures after AAA repair remains unknown. It management to optimize preload and reduce is highly probable that the damage is a conse- myocardial stress, administration of oxygen quence of debris embolizing from the diseased therapy, and adequate postoperative pain relief. aortic wall that is dislodged during proximal Chest infections complicate approximately 5% aortic cross-clamping. Meticulous preoperative of AAA repairs and can be minimized by appro- image analysis may highlight this potential priate analgesia without sedation, chest physio- complication before surgery and thus allowing therapy, and early mobilization. modification of the surgical technique. Patients presenting for elective open AAA repair with known renal impairment are at the Hemorrhage greatest risk of postoperative renal failure. Problematic hemorrhage intraoperatively is Administration of renoprotective agents such as usually due to bleeding from the proximal mannitol, frusemide, or dopexamine in these suture line or inadvertent iatrogenic vessel patients may limit this risk, but substantial evi- injury. The renal and iliac veins are particularly dence for this is lacking. susceptible to damage during initial exposure, and all attempts should be made to address this Limb Ischemia before proceeding to aneurysm repair. Difficult Limb ischemia attributable to AAA surgery is dissections in freeing the iliac arteries for seen in 1% to 4% of cases. This is due to clamping are probably best managed with intra- either distal embolization of debris from the luminal balloon occlusion rather than poten- aneurysm sac or more rarely graft thrombosis. tially hazardous clamp application. The microemboli released following AAA repair Generalized postoperative hemorrhage is are usually too small for surgical intervention to most often due to an acquired coagulopathy be warranted, triggering a variety of limb symp- rather than a direct consequence of surgery. toms such as persistent pain, cold, and blue toes. Massive transfusion and hypothermia lead to Rarely, larger emboli may cause postoperative clotting factor deficiencies, low platelet counts, problems, and in this situation operative explo- an impaired coagulation cascade, and altered ration is mandatory. platelet function. Appropriate blood product and platelet transfusion with rewarming is nec- Gastrointestinal essary to reverse these problems and should be guided by serial laboratory coagulation studies A degree of intestinal dysmotility after laparo- and hematology advice. tomy (“ileus”) is very common and usually 202

VASCULAR SURGERY settles with bowel rest and fluid management. descending thoracic or upper abdominal aorta. Removal of the nasogastric tube should not Interruption of spinal blood flow through col- be too premature, and reintroduction of a lateral vessels by compromising internal iliac normal diet must not occur until there is objec- artery perfusion may also result in paraplegia, tive evidence of returning bowel function (e.g., but this is more frequently seen in conjunction flatus). with systemic hypotension as experienced The most severe gastrointestinal following during ruptured AAA. open AAA surgery is colonic ischemia.This con- Careless dissection may damage the impor- dition, fortunately, occurs much less often then tant autonomic neural pathways found on the ileus, in about 1% of open AAA repair. The left side of the infrarenal aorta. The true inci- cause of this potentially fatal complication is dence of impotence and retrograde ejaculation explained by inadequate colonic perfusion via after elective AAA surgery is unknown, but may the IMA or internal iliac artery. It may occur approach 20%. due to inappropriate IMA ligation (see earlier), inadvertent collateral vessel damage during IMA ligation distant from its origin, or internal Late Complications iliac artery thrombosis or embolism. Sinister Delayed complications arising from open AAA postoperative symptoms include bloody diar- surgery are infrequent and can be classified as rhea, left iliac fossa pain, and an explained high graft or wound related. intravenous fluid requirement. Graft-related late complications include false In cases of colonic ischemia, urgent aneurysms (0.2% to 1.2% at 3 years) due to colonoscopy is indicated, and management is anastomotic disruption, graft infection, and dependent on the findings. Patchy areas of aortoenteric fistulas. Data suggest that the com- partial bowel wall ischemia and sloughing may bined likelihood of infection or fistula at 10 well settle with conservative bowel rest and years is approximately 5% and is much more intravenous antibiotics. Severe bowel ischemia, likely if a femoral anastomosis is used. which is evident as a full-thickness infarction, Long-term wound disorders such as poor requires urgent resection of the affected colon cosmesis requiring revision or hernia depend with end-colostomy. on both surgical technique and perioperative factors such as wound infection, nutritional Venous Thromboembolism status, diabetic management, etc. Surgical atten- tion is not required in the vast majority of cases, The incidence of deep venous thrombosis and each presentation should be assessed indi- (DVT) and following vidually on its merits. open AAA surgery is less than is seen with other general surgical operations. This is probably explained by the intraoperative heparin antico- Endovascular Repair of Abdominal agulation administered during surgery. Never- Aortic Aneurysm theless, DVT still occurs in 8% of patients, and that risk should be addressed with sub- The first successful treatment of an AAA by cutaneous prophylactic low-molecular-weight transfemoral endoluminal repair was reported heparin, compression stockings, and early over a decade ago. Since that time, advances in patient mobilization where appropriate. endovascular surgery coupled with a greater experience and understanding of this technique Neurological has led to possibly a viable alternative to open repair in aneurysm management (Woodburn et The most devastating and feared complication al., 1998). The basic principle of endovascular after open AAA repair is that of paraplegia. For- management is the exclusion of the AAA from tunately, this is a rare event in infrarenal surgery the systemic circulation by means of a pre- as compared to thoracoabdominal aneurysm operatively sized deployed stent graft, thus repair. It results following ligation of an abnor- preventing further aneurysm expansion mally low accessory spinal artery (of and elimination of the rupture risk. For this Adamkiewicz), which is usually found in a to be achieved, a self-expanding or balloon- 203

ANEURYSMAL DISEASE expandable device is advanced into the abdom- Type of Endovascular Procedure inal aorta to be released at a position so that the seal is generated both proximal and distal to Three distinct endovascular prostheses are cur- the aneurysmal segment.Depending on the type rently available for AAA repair. All the manu- of repair, the procedure may or may not require factured devices form the proximal seal in the a combined surgical bypass for successful infrarenal aortic segment, but differences exist treatment. in the location of their distal “landing site.” The Suitability for endovascular intervention aorto-aortic straight graft resides entirely in the depends on extensive preoperative investigation abdominal aorta but is only suitable in 5% of of aneurysm morphology, and the limitations of cases amenable to endovascular repair. Bifur- currently available stent graft devices mean that cated stents can be used in 30% of patients, with this approach is not an option in all elective or the distal seals formed in the iliac vessels. The ruptured cases. At present, about 50% to 60% of remainder (65%) of suitable aneurysms may be all elective AAAs could potentially be considered repaired with aorto-uniiliac stent graft devices. for stenting, but this figure is extremely variable This latter method requires a combined surgi- as much debate continues regarding the exclu- cal crossover procedure (usually femoro- sion criteria for the procedure. With current femoral) for maintenance of contralateral lower devices it is generally agreed that the most limb blood supply following radiological important morphological features in assessing embolization or surgical occlusion of the non- aneurysms’suitability for stenting are as follows: graft common iliac artery. an adequate length (>15mm) of infrarenal aneurysm neck with a maximal neck diameter Perioperative Management of 30mm to ensure a good proximal seal; limited vessel tortuosity, defined as vessel angulation The patient should be assessed and prepared for (60 degrees at the neck of the aneurysm and 90 endoluminal intervention as discussed earlier degrees at the iliac arteries); and iliac arteries of for open repair. Adequate appropriate radiol- sufficient caliber (>7 to 9mm) to tolerate the ogical imaging should be obtained to enable passage of the graft as it is admitted into the calibration of both aneurysm and related infrarenal aorta. Features that are severe as rel- vasculature for graft sizing. Informed consent ative contraindications to the procedure include should include the known specific complica- short (<25mm) and wide (>14mm) common tions associated with endovascular repair and iliac arteries and the presence of mural throm- also mention the possibility of conversion to bus in the aneurysmal sac. Funnel-shaped necks open surgery if necessary. The operating room and excessive calcification are absolute con- should be equipped with a C-arm or equivalent traindications to endovascular repair. for intraoperative imaging,and adjunctive input The exciting advances in this arena offer a less is required from both the resident surgical and invasive approach to AAA management so that interventional radiology team. some patients considered unfit for open surgery After anesthesia induction, the patient is may well be candidates for endoluminal repair. appropriately positioned, prepped, and draped. Results of endovascular intervention as com- The procedure commences by surgical cut- pared to open repair are currently being down to the femoral artery to gain access to the assessed with prospective trials such as the arterial circulation. The device is admitted ongoing Endovascular Arterial Reconstruction through the exposed artery and advanced prox- (EVAR) project. At this stage it would appear imally under radiological control until deploy- that endovascular repair offers mortality and ment of the appropriate site for aneurysm morbidity rates similar to those of open surgery, exclusion. Correct graft position and the but stenting has the advantage of a markedly absence of endoleak is confirmed by on-table reduced length of total in-hospital stay and angiography, and the groin is closed in a routine diminished requirement for intensive care and fashion unless a surgical crossover graft is to be high dependency support. The financial advan- performed. At the end of the procedure, the tage of this,however,is offset by the major draw- lower limbs should be assessed for evidence of back of this approach, which is the cost of the graft thrombosis or embolism before transfer to stent graft itself. the recovery area. The patient can be mobilized 204

VASCULAR SURGERY gently the day after surgery, and discharge can Embolization be expected at 5 to 7 days in uncomplicated cases with a satisfactory early postoperative CT Endoluminal stent graft deployment carries scan. Follow-up guidelines currently advise 6- the risk of distal embolization of debris from month CT and plain lumbar spine imaging in the aneurysmal sac. This is particularly true in the first year and then annually thereafter. cases of extensive mural thrombosis, and there- fore the benefits of endovascular repair should be questioned in these circumstances. Shower- Complications of Endovascular Abdominal ing of microemboli may result in renal failure Aortic Aneurysm Repair and leg ischemia requiring amputation. Endovascular AAA repair unfortunately carries with it a distinct spectrum of specific complica- Graft Migration, Dislocation, tions in addition to “routine” causes of postop- and Displacement erative morbidity. Long-term follow-up of endoluminal stenting has shown that the stent devices may migrate, Iatrogenic Vessel Injury resulting in endoleak, dislocating, and jeopard- izing the seal and kink, with potential thrombo- The introduction of guidewires, large-bore sis.The advent of second-generation devices has catheters, and a stent graft poses the risk of arte- attempted to address these problems with rein- rial and proximal vessel injury such as rupture forcement of graft struts and the introduction or dissection. Delayed manifestations of iatro- of suprarenal uncovered fixation. genic vessel damage may present later, with the development of a false aneurysm at the cannu- lation site, and requires prompt surgical repair. Postimplant Syndrome Well described in the literature, postimplant Endoleak syndrome refers to the presence of early back pain and fever without leukocytosis following Endoleak refers to the persistence of arterial endoluminal AAA repair.It lasts for up to 1 week flow of blood into the “excluded” aneurysm sac after insertion. The condition is self-limiting but outside the lumen of the deployed stent and is managed conservatively. graft. It represents one or more of the following processes: incomplete sealing of the proximal or distal landing sites (type I); continued blood Conversion to Open Repair flow into the sac by collateral and lumbar vessels Failure of endovascular management of AAA (type II); an incomplete seal at junctions of may require conversion to open repair, occur- overlapping graft components or ruptured graft ring in 2% of cases. Indications for such fabric (type III); or leakage of blood through a measures include aortic rupture during a porous graft membrane (type IV). The inci- primary stenting procedure,persistent endoleak dence of endoleak is approximately 20% and with failed secondary intervention, and graft may be further classified as immediate, early, infection. or late. Without treatment, the aneurysm may continue to expand, thus carrying the risk of rupture,although most cases seal spontaneously Ruptured Abdominal with thrombosis. Bearing this in mind, the Aortic Aneurysms majority of vascular surgeons initially manage an endoleak with simple observation. If, after a Ruptured aortic aneurysms are uniformly fatal prescribed time period, the endoleak persists or without operative intervention, explaining the rapid aneurysm expansion is observed, further emphasis of AAA management of early detec- interventions such as endoluminal graft exten- tion and elective repair. Unfortunately, the vast sion deployment, band ligation of the aortic improvements in outcome following elective aneurysmal neck, or even open repair may be AAA repair have not simultaneously been wit- indicated. nessed in the emergency situation, and opera- 205

ANEURYSMAL DISEASE tive mortality under these circumstances has samples withdrawn for biochemistry, hematol- remained static over the last 20 years at between ogy, and urgent crossmatch (at least 10 units) of 40% and 70%. Even this estimation can be con- packed red cells and blood products. sidered conservative, as the figure does not take Arguments persist regarding the optimal goal into account community prehospital deaths, of fluid resuscitation in cases of ruptured AAA. and therefore an overall mortality following It has been suggested that overzealous fluid AAA rupture is probably in the region of 80% management runs the risk of a sudden increase to 90%. in blood pressure and hence converting a con- The exact process that triggers rupture of tained leak into a frank rupture. Management an AAA remains unknown. Several factors strategies should aim to keep a systolic blood (discussed earlier) are known to suggest an pressure of 90 mm Hg by infusion of intra- increased likelihood of rupture and the most venous fluids until operative repair can be per- important of these is aneurysm size. formed. Patient response should be assessed with continuous hemodynamic monitoring and a urinary catheter inserted.Early involvement of Clinical Presentation both the surgical and anesthetic team is desir- A high index of suspicion is paramount in able in order to optimize patient status and min- clinching the diagnosis. Any patient with a imize operative delay. known AAA who presents with sudden severe In some stable presentations of suspected abdominal or back pain has a ruptured AAA rupture, radiological imaging may be per- aneurysm until proven otherwise. The difficulty formed to confirm the diagnosis and delineate arises in atypical presentations of patients with aneurysmal anatomy. The investigation of unknown aneurysmal disease leading to detri- choice remains CT scanning. Ultrasound is of mental delays in surgical management. Rup- little benefit due to its inability to reliably dis- tured AAA should feature in the differential tinguish a ruptured AAA. diagnosis of any patient who presents with Operative management for leaking AAA is by unexplained hypertension, severe abdominal open repair by midline laparotomy. Although pain, or cardiac arrest with no prior history of some centers have reported encouraging results, myocardial disease or trauma. endovascular management currently plays little Clinical symptoms of rupture are varied, but role in the management of ruptured AAA. classically comprise sudden back or abdominal Surgery should be expedient, performed by the pain with an episode of collapse, fainting, and most senior available member of the vascular maybe nausea. Examination reveals a pulsatile team. Following incision, brisk but careful dis- mass on abdominal palpation that may or may section should proceed with placement of the not be tender. The patient may be pale, irritable, clamp in the infrarenal aorta, avoiding damage clammy, tachycardic, and hypotensive. Mainte- to the left renal vein. Temporary supraceliac nance of a normal blood pressure may indicate clamping may be performed to initially control a contained rupture, affording the clinician time problematic bleeding and facilitate dissection to confirm the diagnosis with appropriate for later re-siting in the infrarenal aortic imaging prior to surgery. This luxury is not segment. In extreme circumstances, the sur- offered in an uncontained ruptured AAA when geon’s fingers or an intra-aortic balloon may be the patient should be taken to the operating used to gain proximal control. Intravenous room for operative repair without delay. antibiotics should be administered to limit graft infection, but unlike in elective cases, intra- venous heparin is not routinely given. Once the Operative Repair of a Ruptured Abdominal aorta is cross-clamped, the operation is then Aortic Aneurysm performed as is described for elective AAA. Perioperative management is aimed at stabiliz- Outcome Following Repair of a Ruptured ing the precarious hemodynamic status of the Abdominal Aortic Aneurysm patient. After an initial brief history and exam- ination, venous access should be secured with Significant postoperative morbidity following at least two large-bore cannulae and blood repair of ruptured AAA occurs in 50% to 70% 206

VASCULAR SURGERY of cases (Heller et al., 2000). This figure repre- belief is now being challenged.An early hypoth- sents both suboptimal patient preparation for esis suggesting the periaortic fibrosis was sec- major surgery and the sequelae of prolonged ondary to retroperitoneal blood leakage from hypotension experience pending operative tiny perforations in a previously noninflamma- repair. Cardiorespiratory disorders and renal tory aneurysm has been rejected. Similarly, impairment are the most commonly encoun- other theories of an initial prodromal athero- tered complications, closely followed by sclerotic AAA developing into an aneurysm of ischemic colitis. The latter condition carries a inflammatory type remain unproven. The sug- subsequent mortality of 25% and results from gested mechanism for this transformation is by gut hypoperfusion secondary to aneurysm either lymphatic vessel compression by the rupture. The clinician should anticipate its expanding aneurysm resulting in stasis, edema diagnosis. and subsequent fibrosis, or as a direct conse- Assuming operative survival, patients with a quence of an inflammatory reaction between ruptured AAA enjoy a long-term prognosis as blood in the aneurysmal sac and the aortic governed by their other comorbidities. Repair wall. Viral infection with herpes simplex or has not been shown to diminish the patient’s cytomegalovirus has also been proposed as a quality of life postoperatively, and no different causal factor, with evidence of their presence exists in outcome should the aneurysm have in the aortic wall proven by DNA polymerase been repaired electively. reactions. A more convincing theory regarding inflam- matory AAA development is that it is the result Inflammatory Abdominal of a specific inflammatory process. This process Aortic Aneurysms is responsible for both inflammatory and noninflammatory AAAs, and thus we are not An important subdivision of infrarenal aortic to consider the two pathologies as distinct aneurysmal disease is the inflammatory aortic pathological entities; rather, the former is an aneurysm (Rasmussen and Hallett, 1997). “inflammatory variant” of the latter. There Inflammatory AAAs were not classified per se seems to be good evidence for this theory. until the early 1970s, and even today their Initially, histological analysis revealed the nature in terms of being a distinct clinical and presence of a chronic inflammatory infiltrate pathological entity is still disputed. present in the walls of inflammatory and Definition of the inflammatory AAA depends noninflammatory aortic aneurysms, with the on the presence of a triad of factors: a thickened only difference being an augmented level of aneurysmal wall, marked perianeurysmal/ inflammatory response in the putative inflam- retroperitoneal fibrosis, and dense adhesions matory AAA. This finding was then supported involving adjacent abdominal viscera to the by serial observations of a progressive inflam- aneurysm. These aneurysms comprise 5% to matory response from the initial atherosclerotic 10% of all AAAs, and the typical patient is a to the inflammatory AAA proven both under male in his sixth decade. Females are rarely the microscope and radiologically. It is sug- affected by the disease (male-to-female ratio of gested that there is a primary inflammatory 20:1). Interestingly, the average age at diagnosis reaction to an antigen present in the aortic wall is about 10 years younger than those patients whereby there is gradual infiltration of B lym- presenting with noninflammatory aortic phocytes, T lymphocytes, and macrophages. aneurysms. Postulated risk factors that are Subsequent cytokine production from the specific for the development of inflammatory infiltrate triggers a proteolytic cascade with AAA include cigarette smoking and a genetic increased turnover of MMPs, elastin, and colla- predisposition. gen.With time the aortic wall begins to degrade, There is currently much debate regarding the losing tensile strength, and the aneurysm etiology and pathogenesis of the inflammatory begins to develop. It is proposed that this AAA. Until recently, it was generally upheld that inflammatory response is accentuated further these aneurysms were of a distinct exclusive in smokers and those with a genetic pre- nature and therefore to be considered different disposition, explaining an earlier presentation from their noninflammatory counterpart. This of aneurysmal disease. 207

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Clinical Features Surgical Intervention for Inflammatory The inflammatory AAA is typically sympto- Aortic Aneurysms matic with only 20% cases being discovered At laparotomy the inflammatory AAA is easily incidentally. Classically, the presence of abdom- recognized with its thickened aortic wall and inal or back pain, weight loss, and an elevated shiny, smooth white appearance. There is ESR in patients with a known AAA confers periaortic and retroperitoneal change with a diagnosis of inflammatory aneurysm until adhesions invariably involving the duodenum proven otherwise. Clinical examination may and less commonly the inferior vena cava and reveal a pulsatile mass on abdominal palpation left renal vein. Disease affecting the ureters and generalized evidence of weight loss. Specific occurs in 20% to 40% of cases,which may neces- blood tests to be taken if an inflammatory AAA sitate a team approach with both the vascular is suspected are an ESR, which will be raised in surgeon and urologist. 70% cases signifying the acute phase response, Aneurysm repair should proceed with as and less reliably a white cell count. Serum elec- little dissection as possible. The propensity of trolytes and creatinine should also be taken to these aneurysms to bleed compounded by the look for evidence of obstructive uropathy and high risk of iatrogenic damage to neighboring associated chronic renal failure (10% to 20% of structures poses potentially high surgical mor- patients). bidity. Early inflammatory AAA surgery with futile attempts at periaortic adhesiolysis were Diagnosis complicated by needless duodenal enterotomies and inadvertent venous and ureteric injury, and Despite symptomatology and available labora- this approach to repair has now been discarded. tory investigations, the inflammatory AAA still The method of surgical repair is otherwise tends to be a diagnosis that is made at opera- as previously described for noninflammatory tion. Preoperative CT scanning can sensitively infrarenal AAAs, and operative mortality rates detect aneurysm wall thickening and peri- for elective inflammatory AAA repair should be aneurysmal fibrosis but depends on the radiol- comparable (3% to 4%). Ureterolysis at the time ogist’s awareness to make the diagnosis. of AAA repair remains a controversial issue. Although ultrasound remains useful in routine Over half of inflammatory AAAs demonstrate AAA surveillance, it is less helpful than CT in ureteric involvement on preoperative CT scan- distinguishing the inflammatory variant. If ning. We advise that such ureteric surgery be there is any suspicion of ureteric involvement by reserved for those exhibiting signs or symptoms the retroperitoneal fibrosis,an intravenous pyel- of obstruction or proven incipient uropathy on ogram should be requested. preoperative investigation. Early consultation with the urology team is advisable in these circumstances. Management Although inflammatory aneurysms are usually Thoracoabdominal larger than their atherosclerotic counterpart, it is generally accepted that the risk of rupture is Aortic Aneurysms lower. Presumably this is due to the paradoxical strengthening of the periaortic tissue by fibrotic Aneurysmal diseases affecting both the abdom- change. Some clinicians advocate administra- inal and thoracic aorta are known collectively as tion of oral corticosteroids in an effort to atten- thoracoabdominal aortic aneurysms (TAAAs). uate the inflammatory aneurysmal response, In clinical practice these essentially refer to but there is no evidence to support this. In fact aneurysms arising above the celiac axis. Previ- there is a body of opinion that suggest steroid ously considered as quite a rare condition, therapy may actually increase the risk of recent advances in clinical diagnostic capability inflammatory AAA rupture by a reduction in by methods such as angiography, CT, and MRI the protective fibrosis. Ultimately, surgery suggest that these aneurysms in fact account for remains the treatment of choice for inflamma- up to 10% of the aortic aneurysm population. tory AAA. The management of these patients is complex 208

VASCULAR SURGERY and indeed may fall into the realm of both the ifests as chest pain. The pain is central and radi- vascular and cardiothoracic surgeon. It is there- ates through to the upper back, depending on fore suggested that these aneurysms are best the neighboring anatomy (e.g., spinal nerves or dealt with at a tertiary referral center with vertebral column erosion). Irritation of the appropriate expertise and not routinely at the recurrent laryngeal nerve and bronchial struc- district general hospital. tures may result in voice changes, stridor, and dyspnea. Gradual unexplained orthopnea, Etiology paroxysmal nocturnal dyspnea, and ankle swelling all indicate a failing myocardium, and Atherosclerosis is the most commonly impli- this may be due to a compromised pulmonary cated factor in the development of TAAA circulation by TAAA compression. Occasionally, disease. The classical fusiform aneurysm that if the abdominal component of the TAAA is results is typically seen in men over the age of large enough, the clinician or even the patient 50 years, usually with evidence of arterial may discover a pulsatile mass. Occult symptoms atherosclerotic pathology elsewhere. In fact, of distal embolization should always arouse sus- over half of TAAA presentations are subse- picion of an ongoing proximal aneurysmal quently discovered to have coexistent aneurys- process, thus necessitating appropriate investi- mal disease at an alternative site including the gation for exclusion of TAAA. infrarenal aorta and femoral and popliteal arteries. Other causal factors to be excluded are thoracic dissection with secondary aneurysm Ruptured Thoracoabdominal formation, cystic medial necrosis (e.g., Marfan Aortic Aneurysm syndrome, Takayasu disease, trauma leading to A TAAA rupture can be varied in its clinical false aneurysm), and infection. Previously the presentation. There is usually a history of acute most common cause of this type of aneurysm, severe chest pain, and examination may reveal a syphilitic aortitis leading to the classical Craw- hemodynamically unstable patient requiring ford type I (see later) saccular TAAA, has now vigorous resuscitation. The site of rupture thankfully declined and is rarely seen nowadays and possible involvement of other thoracic in non–Third World practice. structures govern other associated symptoms. Massive hematemesis may result if rupture Clinical Features occurs into the esophagus, whereas hemoptysis and dyspnea suggests the possibility of rupture Clinical presentation of TAAA can be catego- into the tracheobronchial tree. Hemorrhage into rized as asymptomatic, symptomatic but not the pleural cavity or retroperitoneal space can ruptured, and ruptured. often result in a more delayed and profoundly hypovolemic presentation. Asymptomatic Thoracoabdominal Aortic Aneurysm Diagnosis The vast majority of TAAAs are without Examination of a standard chest radiograph symptoms. Unlike infrarenal and peripheral may reveal a widened mediastinum, loss of tho- aneurysms, it is also improbable that routine racic aorta outline, or a “mass” extending into clinical examination will yield the diagnosis. In the left hemithorax. Calcification in the wall of these patients it is the review of the chest radi- the aorta is seen in about one third of patients. ograph that initially arouses clinical suspicion In cases of TAAA rupture into the pleural space, of TAAA, for further investigations to confirm. evidence of a hemothorax should be seen. Confirmation of the diagnosis is achieved by Symptomatic Nonruptured spiral CT scanning, which usually gives all the Thoracoabdominal Aortic Aneurysm required preoperative information regarding aneurysm size, visceral artery relation, and Symptomatic TAAAs usually result from local proximal extent of aneurysm. Magnetic pressure effects, and this most commonly man- resonance imaging techniques are equally 209

ANEURYSMAL DISEASE instructive, but their availability and cost limits proposed surgery.Required investigations are as their use. Unlike investigation of infrarenal outlined in the workup for AAA repair, with an aneurysms, ultrasound for TAAAs offers unreli- emphasis on rigorous optimization of car- able and poor quality results; hence, it plays no diorespiratory and renal status. role in either radiographic diagnosis or surveil- lance. Angiography is indicated only if CT scan- Open Repair of Thoracoabdominal ning does not give sufficient information Aortic Aneurysm regarding relationships to visceral (especially renal) arteries and for the evaluation of possi- Following appropriate patient positioning, ble visceral artery stenoses. draping, and skin preparation, a left-sided thoracoabdominal incision is performed. In Classification high aneurysms (types I and II) some surgeons advocate the use of extracorporeal circulation Classification of thoracoabdominal aneurysms with atriofemoral or femorofemoral cardiopul- is into one of four types as described by Craw- monary bypass to reduce the increased after- ford: load and left ventricular strain induced by thoracic aorta cross-clamping. If this maneuver Type I: Aneurysm involves the descend- is not performed, the requirement for expedient ing thoracic aorta as far as visceral surgery is further augmented. The thoracic and artery branches abdominal aorta are dissected out to enable Type II: Aneurysm extends from the aortic proximal and distal control through nona- arch, just distal to the left sub- neurysmal aortic (and possibly iliac) cross- clavian artery as far as the aortic clamping. Under normal circumstances heparin bifurcation (involves visceral is not routinely given prior to clamp application arteries) to avoid unacceptable blood loss. An appropri- Type III: Aneurysm commences in the ately sized inlay prosthetic graft is introduced midthoracic aorta and extends to after opening the aneurysmal sac, and the prox- the aortic bifurcation imal anastomosis is performed by continuous Type IV: Aneurysm starts at or just below Prolene suture end-to-end with the thoracic the diaphragm but above the renal aorta distal to the left subclavian artery. After arteries and extends as far as the confirmation of proximal anastomosis integrity, aortic bifurcation the visceral vessels (celiac axis, superior mesen- teric, and renal arteries) are then reimplanted Of the four types, surgical repair is carried out into the graft with sequential clamping in order most often on type IV. to minimize organ ischemic time. Most high intercostal arteries are oversewn, but those in Management of Thoracoabdominal the region of T10 to L2 must be reimplanted for Aortic Aneurysm preservation of spinal cord blood supply. After verification of successful vessel anastomosis As in all surgery a balance must be struck with evidence of perfusion, the distal anasto- between the high morbidity and mortality of mosis is formed at the level of the aortic bifur- operative repair, with a reported 5-year survival cation or iliac vessels. The aneurysm sac is of 20% in nonoperative management. Aneurys- closed over the graft and the patient closed in mal size is important, and as general rule, routine fashion. Postoperatively, the patient is asymptomatic aneurysms are not considered transferred to the intensive care unit for close for intervention unless maximal diameter observation. exceeds 6cm. This threshold may be reduced in The nature of type I and type IV thoracoab- saccular pathology due to the increased propen- dominal aneurysms may permit modifications sity to rupture. to the outlined surgical technique in operative Extensive preoperative preparation is man- management. In certain low type IV aneurysms, datory in order both to exclude patients with a “rooftop” abdominal incision can be used for insufficient physiological reserve to survive a total transabdominal access without the operation and to allow adequate planning of need for thoracotomy. The abdominal aorta is 210

VASCULAR SURGERY approached retroperitoneally with mobilization complications postoperatively. Renal failure of the spleen, left kidney, and bowel to the con- requiring replacement therapy with dialysis tralateral side. A vascular clamp can then be occurs in 10% and is more likely in those with applied to the suprarenal aorta to allow an preoperative renal dysfunction. oblique proximal anastomosis to be performed, Postoperative paraplegia and paraparesis incorporating a tongue of native aorta from remain the most feared legacy of thoracoab- which the celiac axis and superior mesenteric dominal aneurysmal surgery. In spite of the out- and renal arteries emerge. Once achieved, the lined operative measures to reduce this risk, clamp is reapplied infrarenally to allow organ type I and II repairs are associated with a 15% perfusion following minimal ischemic time. to 20% chance of paraplegia compared to 5% to Certain type I aneurysms may be approached 10% occurring after types III and IV surgery. In with the need for thoracotomy only. In a similar general terms, higher thoracic aorta clamping manner to type IV repair, the distal anastomo- equates to an increased risk of paraplegia, and sis can be obliquely fashioned to incorporate a this is supported by reported paraplegia rates reversed tongue of native vessel from which the of<1% for low type IV repairs performed by a visceral arteries originate and so limit organ total abdominal approach. Informed patient ischemic time. consent must include detailed discussion with Perioperative spinal fluid drainage is sug- respect to these risks prior to operative repair. gested as an adjunctive measure to lessen the If paraplegia does result from surgery, the clini- risk of neurological complication. The tech- cian should make immediate referral to the local nique aims to optimize spinal cord perfusion by spinal rehabilitation team for early physiother- enabling regulation of the increases in spinal apy and patient support. fluid pressure that result from aortic cross- Mortality rates following TAAA repair are clamping. A fine-bore intrathecal catheter con- variable. Assuming appropriate case selection nected to a pressure transducer is introduced and sufficient surgical expertise, acceptable between the fourth and fifth lumbar vertebrae. operative mortality rates of 10% to 15% for If a potentially deleterious rise in spinal fluid types I and II aneurysms and 5% to 8% for types pressure are observed, fluid drainage by a tap is III and IV are observed. Attempted repair performed to correct it. The catheter is removed of ruptured TAAA transmits inferior results, once normal neurological function is confirmed and postoperative death rates are reported as in the early postoperative period. between 40% and 60%. If operative survival is accomplished, the patients’ long-term prognosis Endovascular Repair of Thoracoabdominal is good and nearly two thirds of operated Aortic Aneurysm patients are alive at 5 years. Endoluminal stent grafting may treat suitable descending thoracic aneurysms without vis- Peripheral Arterial Aneurysms ceral artery involvement. The principles of graft deployment were discussed earlier, with the Aneurysmal disease affecting the nonaortic exception that the aneurysmal neck is ideally arterial vasculature may occur in isolation or situated at least 25 mm distal to the left subcla- more commonly as part of a generalized vian artery. More proximal pathology may still systemic arterial dilatation. It is for this reason be considered in the knowledge that compro- that a thorough examination of all susceptible mised upper limb perfusion due to subclavian vessels should be performed after the artery occlusion would require either operative initial assessment of the presenting peripheral reimplantation into the carotid artery or a aneurysm. carotid-subclavian bypass procedure. Popliteal Arterial Aneurysms Outcome of Thoracoabdominal Aortic Aneurysm Repair Popliteal aneurysms are the commonest nonaortic aneurysms, accounting for 70% of all As with AAA repair, cardiorespiratory morbid- diagnosed peripheral aneurysms (Dawson and ity remains the most frequently encountered van Bockel, 1997). Defined as an external diam- 211

ANEURYSMAL DISEASE eter of one and a half to two times the normal Diagnosis proximal vessel, the true prevalence and inci- dence of the disease remains unknown. That The diagnosis of popliteal aneurysm should be said, it is estimated currently that approximately suspected if an exaggerated pulsation is discov- five patients present to a major vascular center ered on palpation behind the knee during clin- on an annual basis with such lesions. Males in ical examination. A firm pulseless mass in the their sixth and seventh decades are most fre- popliteal fossa may indicate a thrombosed quently affected, and the aneurysms are bilat- aneurysm, especially if an aneurysm is found on eral in around half of patients; 6% to 12% of examination of the contralateral limb. Further presentations have a coexistent AAA. information regarding the lump should then be The majority of popliteal aneurysms are obtained by appropriate imaging. associated primarily with atherosclerosis but Arterial duplex scanning is cheap, easily other etiologies include trauma, infection, and available, and therefore ideal for diagnosis popliteal artery entrapment syndrome. These confirmation, sizing, and subsequent popliteal should always be considered, especially in the aneurysm surveillance. Arteriography is of less younger patient. The aneurysms occur above use in the estimation of aneurysm size, but is the knee joint and are either fusiform or saccu- paramount in the assessment of the regional lar in nature. The beaded fusiform popliteal vasculature for determination of planned surgi- aneurysms tend to be smaller (2- to 3-cm diam- cal intervention. Computed tomograph and eter) than the saccular variety with diameters MRI can offer detailed assessment of the reached of 4 to 6cm. popliteal fossa contents and the nature of the intravascular thrombus content, but their expense and limited availability renders them of Clinical Features little use in the management of the routine About one third of all popliteal aneurysms are popliteal aneurysm. asymptomatic; the diagnosis is made only after investigation of a lump in the popliteal fossa found on a routine clinical examination. The Management of Symptomatic remaining two thirds are symptomatic and Popliteal Aneurysms reflect the complications of these aneurysms: Acute Ischemia and Rupture limb ischemia, rupture, or local pressure effects. Limb ischemia remains the commonest pres- Presentation of a pale,pulseless,cold,and pares- entation and is due to either aneurysmal sac thetic leg signifies an immediate threat to limb thrombosis or distal embolization of intraa- viability, and prompt intervention is needed to neurysmal clot. The emergence of ischemia avert primary amputation. There are a variety (acute or chronic) is dependent on the presence of surgical procedures with adjuvant therapy of an established collateral circulation. In the (thrombolysis) for repair, depending on the more frequent case of acute thrombosis, such a aneurysm’s size, embolic potential, and the circulation is usually poorly developed, and status of proximal and distal vessels. presentation is typically that of acute severe Ideally, a preoperative angiogram should be ischemia with threatened limb viability. Chronic obtained and the patient taken for arterial recon- thrombosis of popliteal aneurysms affords more struction without delay. The aim of surgery is time to the surgeon, resulting in one or more of limb preservation and popliteal aneurysm exclu- symptoms of claudication, rest pain, blue-toe sion. After adequate exposure by either the syndrome, or gangrene. medial or the posterior approach (see later), the Local pressure effects of popliteal aneurysms aneurysm is excluded by means of ligation may cause edema by compression of the adja- and bypass grafting, inlay grafting, or resection cent popliteal vein and even local or referred with primary anastomosis. There should be a pain by irritation of the neighboring sciatic low threshold for performing an additional fas- nerve or its derivatives. Rupture of popliteal ciotomy as indicated by the individual clinical aneurysm is a rare presentation, necessitating picture. immediate surgical attention in order to pre- Bypass grafting after proximal and distal serve the limb. aneurysm ligation remains well established and 212

VASCULAR SURGERY is the usual technique employed. The conduit deterioration is unlikely due to the established may be prosthetic graft or preferably autoge- collateral circulation. Distal embolization, on nous saphenous vein if available. Improved the other hand, involves a persistent blood flow distal run-off can be achieved by the intra- through the aneurysm (unlike thrombosis), operative use of balloon-tipped embolectomy putting the patient at risk of further embolic catheters, and enhanced perfusion following episodes and worsening limb ischemia unless surgery should be confirmed by an on-table the aneurysm is surgically excluded. angiogram. The commoner complications of this surgery include graft thrombosis, infection, and deep vein thrombosis. Resection of Management of Asymptomatic popliteal aneurysms is indicated only in the Popliteal Aneurysms larger, saccular type that involves a short Discovery of these aneurysms is usually on segment of popliteal artery,so the resultant end- examination following diagnosis of aneurysmal to-end anastomosis can be performed without disease elsewhere such as the abdominal aorta tension. Great care must be taken in resection to or contralateral popliteal artery. Subsequent avoid damage to the adjacent popliteal vein, and treatment remains a controversial issue with as for this reason some surgeons avoid this method yet no clear guidelines for surgical intervention. of aneurysm repair. The recent trend of aggressive repair in the Thrombolysis has an important role to play in majority of asymptomatic popliteal aneurysms the management of acute symptomatic popliteal is currently under review in an effort to balance aneurysmal disease. In thrombosed aneurysms the inherent surgical morbidity of repair and with acute ischemia, a percutaneous trans- the fact that for many patients their popliteal femoral arterial catheter can be inserted and aneurysm will be associated with no long-term lodged in the aneurysmal thrombus. Infusion of adversity. Review of the literature suggests that thrombolytic agent [recombinant tissue-type following factors favor elective surgery: ane- plasminogen activator (rtPA), streptokinase, or urysm size >2cm, the presence of mural throm- urokinase] is commenced at an appropriate bus (potential embolic source), autogenous dose, and check angiograms are performed at conduit availability, absent ankle pulses (indi- suitable intervals (every 4 to 6 hours) to confirm cating possible “silent” embolization), and a the clinical observations of improved blood long life expectancy. Classical popliteal ane- supply. Angiographic demonstration of ade- urysm exclusion and bypass as described earlier quate run-off is an indication to stop throm- is the operation of choice in this situation. bolytic infusion and proceed to bypass grafting. Endovascular procedures have been described Long periods of thrombolysis carry the risks of in the treatment of popliteal aneurysms but the bleeding and embolization of released intraa- long-term patency rates and outcomes are at neurysmal thrombus. Strict observation for present unknown. excessive hemorrhage and worsening foot ischemia must be adhered to during treatment, and they mandate cessation of the infusion if Surgical Approach in Popliteal they occur. In advanced ischemia with loss of Artery Aneurysms sensation and muscle power, attempts at surgi- cal revascularization should not be delayed, and Access to the popliteal artery in aneurysmal thrombolysis should be restricted to intraoper- surgery is achieved by either the medial or pos- ative use in an effort to clear tibial and peroneal terior approach. vessel run-off. In the medial approach the knee is partially flexed and the skin incision follows the course Chronic Ischemia of the long saphenous vein, taking care to pre- serve the vein for later harvest. The adductor Symptoms of chronic ischemia in popliteal muscles are retracted, allowing entry to the aneurysmal disease may be due to thrombosis popliteal space with decent exposure and better or distal embolization. A conservative nonoper- access to the superficial femoral and tibial arter- ative approach may be considered in the case of ies than with the posterior approach. A further thrombosed popliteal aneurysm, as an acute advantage of this method is that the incision 213

ANEURYSMAL DISEASE may be easily extended without the need for Type 2: aneurysmal disease of the bifurca- patient repositioning. tion, the commencement of the The posterior approach requires the patient profunda femoris (PFA), or the to be prone, and the incision is made between superficial femoral artery (SFA) the heads of the gastrocnemii extending proxi- mally. Excellent exposure of the popliteal artery Clinical Features is achieved, but access to more proximal or distal vessels proves more problematic. Further- Femoral aneurysms may be symptomatic or more, unless the short saphenous vein is to be asymptomatic. The latter group is usually dis- used for bypass, this approach compels a second covered incidentally on clinical examination of incision for vein harvest. a patient with an aneurysm elsewhere or suffer- ing symptoms of chronic limb ischemia. Pre- sentation of a symptomatic femoral aneurysm Femoral Arterial Aneurysms can include a pulsatile groin mass (which may or may not be painful), leg swelling (in large Femoral arterial aneurysms can be divided aneurysms due to femoral vein compression simply into true or false aneurysms. Due to its and deep vein thrombosis), or features associ- ease of accessibility and the trend for more inva- ated with chronic ischemia attributable to sive medical investigation and treatment (e.g., aneurysm thrombosis/embolization. cardiac catheterization, intra-aortic balloon pumps), iatrogenic injury of the femoral artery leading to false aneurysm is a relatively com- Diagnosis mon occurrence. This chapter discusses only Once clinical suspicion has been aroused, the true femoral aneurysms, and false aneurysms diagnosis should be confirmed with a duplex are considered in detail elsewhere. scan. If surgery is being considered (e.g., in Although rare, true femoral aneurysms are CFA thrombosis or embolization), preoperative the second commonest peripheral aneurysm angiography is desirable for further informa- after those affecting the popliteal artery. They tion regarding the proximal and distal vessels. occur in between 2% and 3% of patients with aortic aneurysms and tend to be a disease of elderly men (male-to-female ratio of 30:1). The Management of Femoral Aneurysms condition is frequently bilateral and similar to Symptomatic femoral aneurysms are them- popliteal aneurysms; a coexistent generalized selves an indication for surgical intervention.As aneurysmal process may be manifest in other with popliteal disease, the management of the anatomical sites such as the aortoiliac or asymptomatic case is less clear. It is generally popliteal arteries. Multiple factors are impli- accepted, however, that if aneurysms are >4cm cated in their development including athero- or aortoiliac disease is present (with indicated sclerosis, turbulent blood flow (at proximal surgery), then operative repair is warranted. major vessel bifurcations and infrainguinally), and repeated hip flexion. Other etiologies to exclude are infection, inflammation (e.g., sys- Surgical Repair of Femoral Aneurysms temic lupus erythematosus, Takayasu’s disease), The skin incision extends from a point approx- trauma, and connective tissue disorders (e.g., imately 4cm proximal to the inguinal ligament, Marfan syndrome). following the course of the artery (and thus aneurysm) to a point just distal to the CFA bifurcation. Once proximal and distal control is Classification achieved, heparin and intravenous antibiotics are administered so that aneurysmal repair True femoral aneurysms are distinguished by can be performed. In Type 1 aneurysms, the the Cutler and Darling classification: CFA-restricted disease, may be addressed by Type 1:aneurysm involves common aneurysm resection and insertion of an inter- femoral artery (CFA) only, not the position graft [polytetrafluoroethylene (PTFE)/ bifurcation Dacron]. Repair of type 2 aneurysms is by graft 214

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(autogenous saphenous vein or prosthetic) Management of Iliac Aneurysms interposition with an end-to-end technique between the nonaneurysmal CFA and the larger Management strategies are outlined depending of the bifurcated vessels (SFA or PFA). The on whether the common iliac (CIA) or internal smaller vessel is then reimplanted into the side iliac (IIA) artery is involved. of the graft directly, or by the use of a second graft. Patency rates following repair are good, 80% to 85% at 5 years with a low operative mor- Common Iliac Aneurysms tality and morbidity. Small CIA aneurysms (<3cm) do not require surgery and can be managed conservatively. If the maximal aneurysm diameter lies between 3 Iliac Artery Aneurysms and 4cm, patients should be kept under ultra- sound surveillance (every 6 months) and oper- Isolated iliac aneurysms are rare with a reported > incidence of only 1% to 2% of all aortoiliac ation offered if expansion to 4cm. Isolated CIA aneurysmal disease. The aneurysms tend to be aneurysms may be repaired by means of an large (4 to 8cm), with annual expansion rates interposition graft and oversewing of the IIA comparable to that of AAAs. Males over the age origin. Alternatively, the CIA aneurysm can be of 70 years are most frequently affected,with the ligated (proximally and distally) with execution atherosclerotic process implicated in the vast of an iliofemoral or femorofemoral crossover majority of cases. Other reported etiologies graft. include infection (TB, syphilis), trauma (pelvic fractures and iatrogenic during surgery), inflammation, and pregnancy. Internal Iliac Aneurysms Unilateral IIA aneurysms can be addressed by either radiological or operative techniques. Clinical Features Coil embolization of the IIA successfully ex- Iliac aneurysmal disease may be asymptomatic cludes the aneurysm from the circulation with or symptomatic. Human pelvic anatomy minimal long-term sequelae. Surgical inter- accounts for the fact that even very large iliac vention requires simple proximal and distal aneurysms may remain “silent” until an inci- aneurysm ligation for treatment in these cases. dental diagnosis. Any symptoms experienced Bilateral IIA aneurysms pose an interesting are typically due to local effects on neighboring problem as bilateral aneurysm ligation or structures including the ureter, small bowel, embolization is not a viable option to preserve iliac vein, and femoral or sciatic nerve. adequate colorectal and perineal blood supply. Abdominal examination may reveal the diag- In this scenario an attempt at surgical revascu- nosis but is usually normal. Palpation of a pul- larization should be made. The bypass graft satile mass on rectal or vaginal examination runs from the nonaneurysmal CIA to the distal should alert the clinician to the possibility of IIA with proximal aneurysm ligation. Extensive iliac aneurysmal disease. hemorrhage can often be encountered in this difficult procedure for which the surgeon should be prepared. Diagnosis Duplex ultrasound scanning is cheap, readily Visceral Artery Aneurysms available, and thus the preliminary investigation of choice in diagnosis confirmation. Conven- Aneurysmal disease involving the visceral arter- tional angiography is extremely informative, ies is uncommon but an important cause of but due to contrast load and radiation exposure vascular admission.As imaging techniques con- its use is restricted to preoperative instruction. tinue to improve, there will no doubt be a cor- The cost and availability of spiral CT and mag- responding increase in the diagnostic yield of netic resonance angiography negates their these aneurysms, so it is hoped that manage- use routinely, but the quality of information ment strategies can be applied to the elective obtained remains impressive. rather than the emergency presentation. 215

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Splenic Artery Aneurysms either splenectomy or aneurysmal excision (for splenic conservation) is advocated for distal The splenic artery is the most common visceral disease. Coil embolization performed by a artery to be affected by aneurysmal disease, member of the resident interventional radiol- accounting for 60% of all visceral aneurysms. ogy team may be successfully used to treat They are the second most common abdominal appropriate splenic aneurysms in high-risk aneurysm after the aorta, with an estimated patients. population incidence of 1%. Vessel dilatation is < usually minimal ( 2cm) and about one fifth of Hepatic Artery Aneurysms these aneurysms are multiple. Contrary to aneurysmal disease elsewhere, it is multiparous Aneurysmal disease involving the hepatic artery women who are classically affected. The etiol- accounts for approximately one fifth of visceral ogy of splenic artery aneurysm is unknown, but aneurysms. They occur more often in the male theories include the vascular sequelae of multi- population with an average age at presentation ple pregnancies, altered flow dynamics in portal of 40 years, somewhat lower than is observed in hypertension, and multifactorial vessel wall other aneurysmal processes. Site of aneurysm degradation. formation is either intrahepatic (25%) or extra- Eighty percent of splenic artery aneurysms hepatic (75%), the latter aneurysms being are asymptomatic. The remaining proportion usually solitary affecting the common hepatic may present with a nonspecific pain in the left artery (60%). Isolated involvement of the right hypochondrium or epigastrium that can radiate and left hepatic arteries is less frequent, but if to the left flank or be referred to the left shoul- present, a predilection for the right hepatic der by diaphragmatic irritation. As aneurysmal artery is seen (seven times more common). The progression continues, the symptoms worsen cause of extrahepatic aneurysm is normally ath- and are further aggravated by excessive move- erosclerosis, but factors such as infection, ment. Abdominal examination is usually trauma, and cystic medial degeneration must be normal, although splenomegaly is detected in considered. Conversely, intrahepatic disease 20% of patients. Rupture occurs in 5% to 10% of tends to be false aneurysms resulting from splenic artery aneurysms, and in these cases the trauma. patient presents with severe upper abdominal Nonruptured hepatic aneurysms are usually pain,hypotension (volume loss),and frank peri- asymptomatic but may present with discomfort tonism. Nearly all ruptures occur during preg- in the right hypochondrium or epigastrium. As nancy, and associated mortality rates are high its size increases, the pain radiates into the back. (75% mother, 95% fetus). Sudden development of acute abdominal pain, Diagnosis of splenic artery aneurysms is hypotension, and peritonism indicates rupture usually incidental on imaging modalities such of the aneurysm, occurring in 20% of cases. as plain abdominal radiographs (calcification), Unless the aneurysm has indeed ruptured, clin- angiogram, spiral CT, or MRI scanning. Alter- ical examination is invariably normal, although natively, these lesions may be discovered during detection of a pulsatile mass and bruits have laparotomy for other pathology. Management been reported. planning in splenic aneurysms tends to be Prerupture clinical diagnosis of hepatic dependent on whether symptoms exist. As a aneurysm is problematic. Elevated serum general rule, the majority of asymptomatic amylase, bilirubin, and white cell counts may be aneurysms may be treated conservatively, but in observed, but more often than not diagnosis those experiencing symptoms, surgical inter- depends on ultrasound and CT findings. Once vention is indicated at an early stage. Operative suspected, the investigation of choice for procedure is governed by the anatomical loca- hepatic aneurysm is selective celiac and supe- tion of disease within the splenic artery. Proxi- rior mesenteric angiography. mal aneurysms (in the first third of the splenic Due to high rates of rupture-related mor- artery) are treated by either ligation or excision tality of approximately 40%, proven hepatic and grafting after an approach through the aneurysms merit aggressive management. The lesser sac. Ligation is indicated in aneurysms exact surgical procedure is again guided by affecting the middle third of the artery, whereas anatomical location of aneurysms: for extra- 216

VASCULAR SURGERY hepatic aneurysms proximal to the gastroduo- size. Operative procedures include excision with denal artery, simple aneurysm ligation should direct end-to-end arterial anastomosis, graft be performed (hepatic blood supply maintained interposition (prosthetic or autogenous vein), by gastroduodenal and right gastric arteries); if and nephrectomy. Suitable aneurysms may be the aneurysm location is distal to the com- treated with embolization, but these techniques mencement of the gastroduodenal artery, then carry a significant risk of parenchymal damage. an excision and graft procedure should be attempted. Intrahepatic aneurysm repair is more difficult. Both embolization and limited Superior Mesenteric Artery Aneurysms liver resections have been performed, but not These aneurysms are rare, representing approx- all aneurysms are suitable for coil deployment, imately 8% of all visceral aneurysms. Both sexes and operative mortality in these cases remains are equally affected, with infection implicated as high. the causal factor in two thirds of cases. Other etiologies include atherosclerosis and trauma. Renal Artery Aneurysms Age at presentation is variable, mycotic aneurysms being more common before 50 years Renal artery aneurysms are about as common of age, whereas atherosclerotic aneurysms as hepatic aneurysms, accounting for one fifth usually present later (over 60 years of age). of all visceral aneurysms. The true incidence of Superior mesenteric artery aneurysm man- these aneurysms lies between 0.3% and 1.3%, agement tends to be aggressive, as there is a with less than 10% of those affected exhibiting high rate of rupture whatever the size of the symptoms. They occur in both sexes, with aneurysm. Surgery should attempt to ligate the women of childbearing age considered to be of aneurysm without reconstruction or excision highest rupture risk. Etiologies of renal artery due to the high risk of damaging adjacent struc- aneurysms are varied, but the majority (80% tures. Again, embolization may be considered, to 85%) are caused by the degradation of the but it carries the potentially fatal complication internal elastic lamina at the renal arteriolar of intestinal ischemia. divisions leading initially to microaneurysm formation that then progresses into frank aneurysmal disease. Other factors to consider in Celiac Artery Aneurysms aneurysm development include previous renal Celiac aneurysms are even less common than trauma and generalized arteritis. As already those affecting the superior mesenteric artery, mentioned, the vast majority of these representing 3% to 4% of all visceral aneurysms are clinically silent, but if present, aneurysms. There is an equal sex distribution, symptoms include flank pain on the affected and most are due to atherosclerosis and medial side, hematuria, and systemic hypertension. degeneration. The majority are without symp- Clinical examination may reveal a bruit on aus- toms, but if present they include epigastric pain, cultation. Rupture is manifest by acute localized nausea, and vomiting. A bruit may be heard on pain and hypovolemia due to either retroperi- clinical examination. Diagnosis is confirmed by toneal hemorrhage or rupture into the neigh- CT scanning or abdominal ultrasound, and sub- boring renal vein, resulting in a high-output sequent management involves surgical excision arteriovenous fistula. (for small aneurysms) or reconstruction. Diagnosis is usually made at laparotomy for a different abdominal pathology or incidentally on radiographic imaging such as CT scanning, Gastroduodenal, Pancreaticoduodenal, and angiography, or MRI. Management of asympto- Pancreatic Artery Aneurysms matic, low-risk renal artery aneurysms should be nonoperative, as the procedure carries a Aneurysms of these arteries are extremely rare, significant (5%) risk of nephrectomy. On the collectively accounting for 3% of visceral other hand, “high risk” asymptomatic popula- aneurysms. The patient is usually a man in his tions (defined as women of fertile age) and sixth decade with a prior history of pancreati- symptomatic patients should proceed to tis. Symptoms, if present, are of epigastric pain aneurysm repair irrespective of aneurysmal radiating through to the back, and angiography 217

ANEURYSMAL DISEASE or CT scanning reveals the diagnosis. Rupture- plexus irritation, an ipsilateral Horner syn- related death rates are high (about 50%); there- drome from sympathetic chain compression, fore, a low threshold should exist for surgical hoarseness due to recurrent laryngeal nerve repair. Operation is by aneurysm ligation, or pressure, stridor due to partial extrinsic tra- in suitable cases coil embolization may be cheal obstruction, and upper limb edema appropriate. caused by venous outflow obstruction. Pul- monary erosion by the aneurysm explains any hemoptysis, whereas distant manifestations of Jejunal, Ileal, and Colic Artery Aneurysms the condition can include acute or chronic limb Together these aneurysms constitute 2% to ischemia from thromboembolism and Raynaud 3% of all visceral aneurysms. Sex distribution syndrome. Examination may reveal a supraclav- appears to be equal, with an average age at pres- icular pulsatile mass with an audible bruit. An entation of 75 years. These aneurysms tend to assessment of full upper limb neurovascular be small, isolated, and asymptomatic until status is mandatory, which classically reveals rupture. Diagnosis is invariably made at sub- normal pulses in the evidential face of prior sequent laparotomy, where repair is by either microembolism and altered neurology in the aneurysm ligation or excision. Concomitant corresponding segment of brachial plexus or limited bowel resection may have to be per- sympathetic chain. formed if the vascular repair threatens an Duplex or CT scanning confirms the diagno- inadequate intestinal blood supply. sis of SCA, but angiography is also required to plan appropriate intervention. Proximal SCA management is by resection with end-to-end Axillary and Subclavian anastomosis for (small aneurysms) or by surgi- Artery Aneurysms cal resection with interposition arterial graft. Proximal vascular control can be difficult, Aneurysmal disease affecting the upper extrem- and occasionally sternotomy (right SCA) or ity is rare but remains of importance due to the extended thoracotomy (left SCA) is required. severity of possible sequelae associated with the Surgical correction of the distal SCA adheres to disease. Ideal management, therefore, aims at the same principles as for proximal pathology, early diagnosis and repair in order to minimize with the advantage that adequate exposure is this potential morbidity. Pathology in this achieved by simple supraclavicular incision. region is divided anatomically into one of three types, each with a distinct etiology. Axillosubclavian Artery Aneurysms Subclavian Artery Aneurysms These aneurysms involve the junction between the terminal subclavian and proximal axillary Subclavian aneurysms (SCAs) are arbitrarily arteries at the border of the first rib. They are classified as proximal or distal in reference to invariably poststenotic aneurysms from a tho- the location of diseased arterial segment. Prox- racic outlet syndrome caused by either a cervi- imal aneurysms are totally confined to the cal rib or fibrous band. The disease is more parent artery and are usually caused by degen- common in younger females, probably because erative disease, trauma, or infection. They occur it is this population that has the highest inci- more commonly in men and over the age of 60 dence of cervical rib. years. In contrast, distal subclavian aneurysms Symptoms are similar to those outlined for tend to occur in the younger female population. isolated subclavian aneurysms, but it is worth Clinical features associated with SCA can be noting that there is an increased frequency of considered as local or distant. The patient may embolic phenomena. Investigation of axillosub- complain of a painless pulsatile mass in the clavian disease is initially by duplex ultrasonog- lower neck, whereas acute aneurysm expansion raphy, but arteriography is advised for all cases or rupture causes pain experienced in the chest, to be considered for surgery. Exact management neck, or shoulder. Local symptoms due to com- depends on both aneurysmal size and the pres- pression are common and include neuropathic ence of distal thromboembolic complications. pain (which may be referred) due to brachial Large (defined as more than twice the arterial 218

VASCULAR SURGERY diameter) or symptomatic aneurysms require be painful. Other symptoms are attributed to arterial repair by means of excision and graft local compression and include dysphagia as a interposition with synchronous removal of the result of pharyngeal proximity, deafness or antecedent cause (e.g., excision of cervical rib or facial pain due to cranial nerve compression, division of fibrous band). Small, asymptomatic and hoarseness caused by vagus nerve impinge- aneurysms may well recede once the thoracic ment.Distal central nervous neurological symp- outlet syndrome has been surgically corrected toms such as stroke, amaurosis fugax, or so that arterial reconstruction is often not transient ischemic attack (TIA) indicate throm- required. boembolic complications from the carotid aneurysm and are in fact the most common pre- Axillary Artery Aneurysms senting feature of the disease. Large aneurysms have also been implicated in posture-related Isolated axillary artery aneurysms are very rare transient neurology as a result of limitation and but typically affect young males as a conse- even occlusion of blood flow through the neigh- quence of trauma. Repeated blunt trauma to boring internal carotid artery. Ruptured carotid the axillary artery, classically due to long-term aneurysms are fortunately rare but are usually crutch-use, may result in aneurysm develop- fatal if they occur. ment and the subsequent complicating symp- It is interesting that despite the paucity of toms of acute or chronic upper limb ischemia. the disease, carotid aneurysms remain over- Penetrating trauma tends to result in false diagnosed. True aneurysms must be distin- aneurysm formation. A rich collateral blood guished from the much commoner reality of supply in this region may lead to delayed and tortuous or coiled carotid vessels, and other atypical presentations, so a high index of suspi- diagnoses such as cervical lymphadenopathy, cion is needed to make the diagnosis. carotid body tumors, and branchial cysts. In the Investigation is by duplex ultrasound fol- majority of cases history and clinical examina- lowed by arteriography, and appropriate tion alone should be sufficient to expose the surgery is aneurysm resection and arterial bona fide aneurysm, but confirmation can be reconstruction by interposition autogenous obtained with duplex or CT scanning. If inter- vein graft (saphenous vein). Prosthetic grafts vention is being contemplated, an angiogram have been successfully used but are associated must also be obtained. with inferior long-term patency rates. Recently, The aim of management is ultimately pre- successful management with axillary endovas- vention of the neurological complications cular stent grafts has been reported, but the associated with carotid aneurysmal disease. long-term results of this intervention are Current opinion regarding preferred treatment presently unknown. is divided between surgical and endovascular methods. In the former, the aneurysm is Carotid Artery Aneurysms resected, arterial reconstruction is performed, and cerebral blood flow is maintained during Extracranial carotid aneurysmal disease requir- carotid clamping with an operative shunt. The ing vascular surgical expertise is extremely rare. adequacy of this maneuver is assessed by some True carotid aneurysms are located either in surgeons with the use of intraoperative tran- the carotid bifurcation, internal carotid system scranial Doppler or electroencephalography in or external carotid, in decreasing frequency of order to confirm distal perfusion. Surgery is that order. Etiological factors are varied, but the notoriously perilous in proximal internal most common include atherosclerosis, trauma, carotid disease and in larger aneurysms where previous carotid surgery (e.g., endarterectomy), “distal” control can be difficult to secure. The and carotid artery dissection. Historically, most feared complication of carotid aneurysm infection used to be the major culprit causing surgery is disabling stroke, occurring in 6% to disease, but widespread antibiotic availability 10% of cases, which may result from cerebral has rendered this mechanism responsible in hypoperfusion or intraoperative dislodgment of only a minority of cases. debris from the vessel wall.Another specific risk The patient may present with an awareness of of surgery is cranial nerve palsy, resulting from a pulsatile mass in the neck that may or may not local tissue handling or careless dissection. The 219

ANEURYSMAL DISEASE condition affects 20% of patients and is usually • Is open repair preferable to endovascular temporary, but must nonetheless be mentioned therapy in elective AAA repair? to the patient preoperatively while obtaining • What is the optimal management of type I informed consent. and type III endoleaks? Endovascular approaches to carotid • Does routine uterolysis have a role in the aneurysm management may soon render management of the inflammatory AAA? surgery as second-line treatment for extracra- • Do all high (Crawford types I and II) tho- nial carotid aneurysmal disease. Graft stenting racoabdominal aneurysm repairs mandate and coil embolization of such lesions is reported the use of cardiopulmonary bypass and to be as effective as surgical repair, without spinal fluid drainage? the need for operation. These techniques may be especially appropriate in large aneurysms, • What is the best treatment for the asymp- revisional surgery, or the case of high carotid tomatic popliteal aneurysm? aneurysm close to the base of skull so that • When should carotid aneurysms be access is problematic. The risk of neurological repaired with endovascular methods? complications following the procedures re- mains, but these cerebrovascular events appear less common in this approach to treatment. Still in its infancy, these initial encouraging results References may be tempered as we await the longer term Dawson I, Sie RB, van Bockel JH. (1997) Br J Surg 84: results of endoluminal intervention. 293–9. Hallin A, Bergqvist D, Holmberg L. (2001) Eur J Vasc Endovasc Surg 22:197–204. Heller JA, Weinberg A, Arons R, et al. (2000) J Vasc Surg Controversial Issues 32:1091–100. Rasmussen TE, Hallett JW Jr. (1997) Ann Surg 225:155–64. • Should there be a national screening Wassef M, Baxter BT, Chisholm RL, et al. (2001) J Vasc Surg program for the detection of AAA? 34:730–8. Wilmink AB, Quick CR. (1998) Br J Surg 85:155–62. • Are all elective AAA repairs best per- Woodburn KR, May J, White GH. (1998) Br J Surg 85: formed at tertiary referral centers? 435–43. 18 Renovascular Hypertension and Ischemic Nephropathy Sherry D. Scovell

Renovascular hypertension is a relatively severe diastolic hypertension, which is defined uncommon cause of hypertension and is only as diastolic blood pressure greater than 115mm seen in 5% to 10% of the hypertensive popula- Hg. In a blood pressure screening program 137 tion. However, this translates to at least 600,000 patients with new-onset hypertension were people in the United States alone when consid- diagnosed in a shopping center. Further workup ering that nearly 60 million people in the United consisted of angiography followed by renal States have some degree of hypertension. Renal vein renin measurements and split renal func- artery stenosis (RAS) often produces an unclear tion tests in patients with evidence of critical clinical picture. Patients may be asymptomatic. renal artery stenosis. None of the 102 patients However, they may also present with severe, with a diastolic blood pressure between 90 uncontrolled hypertension referred to as reno- and 115mmHg had evidence of renovascular vascular hypertension or with evidence of renal hypertension. However, nine of the 35 patients insufficiency, otherwise known as ischemic (26%) with a diastolic blood pressure of 115mm nephropathy. This chapter focuses on the clini- Hg or higher did have evidence of renovascular cal characteristics that may be helpful in iden- hypertension. With respect to race, none of tifying those patients who may be at risk for the African-American patients had renovascu- RAS, how to accurately diagnose RAS, and how lar hypertension, whereas nine of the 22 (41%) to correlate RAS with the symptoms of uncon- Caucasian patients did have renovascular trolled hypertension or ischemic nephropathy. hypertension. It also outlines the options available for treat- Renovascular hypertension has also been ment, including medical management, endo- described as having a bimodal age distribution, vascular correction of RAS via angioplasty with patients at the two extremes of age carry- with or without stenting, and open surgical ing the highest incidence of having renovascu- revascularization. lar disease responsible for their hypertension. It is typically seen in children younger than 5 years old and in patients over 60 years of age. Characteristics Based on observations such as these, addi- tional characteristics thought to be associated With renovascular disease being responsible with renovascular hypertension were postulated for only 5% to 10% of the hypertensive popu- to include recent onset of hypertension, young lation, it would be helpful to define certain age, lack of family history of hypertension, and clinical characteristics that are prevalent in the presence of an abdominal bruit. The most this population to aid in screening patients. comprehensive study used to compare these Typically, renovascular hypertension produces characteristics in hypertensive patients both

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VASCULAR SURGERY with and without RAS was the Cooperative angiographic appearance is that of a string of Study of Renovascular Hypertension (Simon, beads. There are two distinct types of medial 1972). One of the ultimate conclusions of this fibrodysplasia—diffuse and peripheral. study was that neither the above four criteria Perimedial dysplasia is seen in only about nor any other clinical criteria could accurately 10% of patients with FMD. This subtype is again predict the presence of renovascular hyperten- seen most often in women in the fourth or fifth sion. Indeed, the majority of patients with ren- decades of life. This type may be more progres- ovascular hypertension do not present with sive when compared to medial fibrodysplasia. what were once thought to be the “classic” char- Finally, intimal fibroplasia is seen in 5% of acteristics delineated above. As a result of these patients with FMD. These lesions are long, irreg- studies, it is necessary to maintain a high index ular, tubular regions of stenosis. They tend to of suspicion in patients whose hypertension is progress more rapidly than those caused by difficult to control with medical management medial fibrodysplasia. and to rely on screening examinations in patients with severe diastolic hypertension. Pathophysiology

Etiology Any comprehensive review of renovascular hypertension must cite Goldblatt’s (1934) classic The etiology of RAS is primarily atherosclerotic experiments. He described both the two-kidney, in approximately 90% of patients. The second one-clip model of unilateral RAS in the setting most common etiology is fibromuscular dyspla- of a normal contralateral kidney, as well as the sia (FMD). Other less common causes of RAS one-kidney, one-clip model that represents uni- include aortic dissection, vasculitis, emboli, lateral RAS in a patient with only one kidney. radiation, and extrinsic compression from In the two-kidney, one-clip model, one renal masses or tumors. artery is clamped while the other one is left Atherosclerotic renal artery stenosis is seen open. In this model, there is decreased renal predominantly in males. The majority of these blood flow seen by the ipsilateral juxtaglomeru- lesions are believed to be ostial encroachment lar apparatus. This leads to increased secretion of an aortic plaque on the orifice of the renal of renin by the clipped kidney. Through the artery or arteries. As a result, 50% of the time renin-angiotensin-aldosterone system, there is these lesions are bilateral. As well, these lesions mild sodium retention as a result of increased are typically eccentric and irregular luminal aldosterone and increased blood pressure sec- stenoses. It is well known that atherosclerotic ondary to angiotensin II–related vasoconstric- disease is progressive and the renal artery in not tion. The contralateral kidney then suppresses an exception. RAS will be progressive in 30% to its release of renin to compensate. When an 70% of cases. Approximately 11% of the time, angiotensin-converting enzyme (ACE) inhibitor patients with a greater than 60% stenosis of the is administered to a patient in the two-kidney, renal artery will progress to total occlusion one-clip model acutely, there is a dramatic within a 2-year period (Zierler, 1994). reduction in blood pressure. This demonstrates The stenoses caused by FMD are primarily that the elevation in blood pressure is primarily nonostial and often extend into the branches angiotensin II–dependent. of the renal arteries. Fibromuscular dysplasia In the one-kidney, one-clip model of reno- may be divided into three types: medial fibro- vascular disease, a clip is applied to the renal dysplasia, perimedial dysplasia, and intimal artery supplying a single kidney. In this case, fibroplasia. there is an initial elevation in renin. This initial Medial fibrodysplasia is the most common rise in the renin leads to activation of the renin- type, accounting for 85% of all FMD lesions. angiotensin-aldosterone system, and there is Women are predominantly affected, usually peripheral vasoconstriction as well as an between 25 and 45 years of age. In 55% of increase in sodium and water retention. Blood patients, the disease is bilateral. If it is unilateral, pressure rises as a result of both of these mech- it is more likely to affect the right renal artery anisms. This model is both an angiotensin- when compared to the left renal artery. The dependent system as well as a volume-driven 223

RENOVASCULAR HYPERTENSION AND ISCHEMIC NEPHROPATHY system and produces a more persistent form of The degree of RAS is typically calculated hypertension. based on the renal-to-aortic ratio (RAR) as well as the peak systolic velocities in the renal artery. The RAR is the ratio of the peak systolic veloc- Diagnostic Evaluation ity of the renal artery to the aortic peak systolic velocity. If the RAR is less than 3.5 with a peak The patients who are well served by renal revas- systolic velocity of greater than 180cm/sec, cularization are those with severe RAS in the there is a less than 60% stenosis. If the RAR is setting of either uncontrolled hypertension or greater than 3.5 and the peak systolic velocity ischemic nephropathy. Patients without an asso- is greater than 180cm/sec, this is diagnostic ciation between the anatomical stenosis and of a greater than 60% stenosis. If there is no these symptoms are not well served by correc- detectable renal artery signal with a kidney tion of the RAS. Therefore, it is necessary to length of less than 9cm, the renal artery is con- establish a correlation between the anatomical sidered occluded. RAS and the uncontrolled hypertension or Although this is an excellent screening test ischemic nephropathy to determine who will to detect the presence of renal artery stenosis, benefit from an attempt at revascularization. duplex examination is unable to accurately This is done primarily through the combination predict the clinical response of either the hyper- of both anatomical screening tests as well as tension or renal insufficiency following correc- studies that document associated physiological tion of the RAS. It is also unable to accurately consequences. Anatomical tests are those that identify all accessory branches of the renal delineate RAS and document associated hemo- artery and their contribution to the clinical dynamic data. Physiological tests attempt to picture. This is, however, an appropriate nonin- establish an association between the anatomical vasive screening test to evaluate for RAS and is stenosis and the alterations in the renin- useful for following the patient with serial angiotensin-aldosterone axis. examinations after intervention.

Anatomical Tests Angiography/Digital Subtraction Angiography Duplex Ultrasound The gold standard for the identification of RAS Duplex examination of the kidneys and the still remains angiography, although it is an inva- renal arteries is an extremely useful screening sive test and not an optimal screening tool. It modality as it is a noninvasive examination. The serves to define the presence, severity, and loca- only preparation necessary is an overnight tion of intraluminal anatomical defects in the fast, and it is not necessary to discontinue anti- renal artery. It facilitates a full evaluation of hypertensive medications for reliable results. the abdominal aorta as well as the renal artery Renal artery duplex examination is able to iden- orifices and the accessory branches of the renal tify hemodynamically significant renal artery artery. Multiple accessory renal arteries exist in lesions. It offers information on renal length up to 25% of patients and are well defined with as well as on the renal artery blood flow. The angiography. It is able to define a nephrogram. resistive index (RI) indicates the degree of It is still controversial whether angiography renal artery resistance and should be calculated. should be utilized as a screening test for reno- It is defined as the peak systolic shift minus vascular disease. It is likely best used as an the minimum diastolic shift over the peak sys- adjunct when duplex examination is unable to tolic shift. A normal RI is less than 0.70. The RI visualize the renal arteries, or smaller accessory may be predictive of outcome with respect branches are suspected of contributing to severe to renal revascularization (Radermacher et al., renovascular hypertension. 2001). However, caution should be taken in Technically, the renal arteries usually arise the interpretation of RI as it may also be in- posterolaterally from the aorta and require creased in patients with intrinsic renal disease, oblique views for adequate visualization of their decreased cardiac output, or perinephric fluid orifices. Peak systolic pressure gradients across collections. the lesion of >20mmHg or mean gradients of 224

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10mmHg have been used as objective criteria to with the addition of an ACE inhibitor, as well as define a significant reduction in blood flow. renal dysfunction not attributable to another It has been well documented that angiogra- obvious etiology. Finally, recurrent episodes phy may exacerbate renal failure in patients of “flash” pulmonary edema not able to be with baseline renal insufficiency. Nonionic, low- explained on the basis of severe left ventricular osmolar contrast material is recommended dysfunction in the setting of RAS was also con- for the evaluation of the renal arteries and is sidered an indication for revascularization. The associated with a lower incidence of contrast- value of prophylactic renal artery revasculariza- induced nephropathy (Barrett and Carlisle, tion in asymptomatic patients is unproven at 1993). In patients with an elevated creatinine, this point, and that is why physiological tests are CO2 or gadolinium may be substituted without significant in these patients. an increase in contrast-induced nephropathy.As well, preintervention hydration is critical as is Physiological Tests acetylcysteine in select patient groups. The calculation of RAS is determined by com- When a unilateral RAS is defined by anatomical parison of the narrowest segment of the renal studies, the functional significance must be artery to the normal diameter of the renal artery determined. In the past, many different tests either proximal to the stenosis or distal to any were attempted in order to define this correla- region of poststenotic dilatation. Poststenotic tion including intravenous urography, nuclear dilatation is common in many cases of long- medicine studies, conventional angiography, standing arterial stenosis. computed tomography,and magnetic resonance imaging. More recently, this is accomplished Patient Selection through the use of renal vein renin assays or by isotope renography. The value of these tests is Renal artery stenosis alone, in the absence of not as great in patients with severe bilateral symptoms, does not mandate repair. The coex- renal disease or RAS in a solitary kidney when istence of RAS and hypertension does not compared to unilateral renal disease and a func- establish a causal relationship. For this reason, tioning contralateral kidney. it is essential to determine the functional Physiologically, there is a functional increase significance of the anatomical stenosis. in plasma levels of renin from the affected Patients with RAS and symptoms attributable kidney, which is characteristic in the setting of to that stenosis are considered for treatment and RAS. Originally, systemic levels of renin were correction of the anatomical lesion. Symptoms obtained in an attempt to establish a diagnosis. of hypertension, renal insufficiency, or pul- However, utilizing this method, the rate of false- monary edema in the setting of a greater than negative and false-positive results were high, 60% RAS serve as criteria for repair. Clinical cri- 43% and 34%, respectively, in patients with teria for revascularization have been defined confirmed renovascular hypertension. As well, recently in the Guidelines for Reporting on roughly 20% of patients with essential hyper- Renal Artery Revascularization in Clinical Trials tension had an elevated plasma renin level. The (Rundback, 2002). Based on these guidelines, value of selective renal vein sampling of renin, hypertension was classified as either accelerated although an invasive procedure, has been found with sudden worsening in the setting of previ- to be more sensitive and specific. This test com- ous control, refractory hypertension resistant to pares the renin levels between the ipsilateral medical management with three or more anti- and contralateral kidneys.If the renal vein/renin hypertensive medications including a diuretic, ratio is greater than 1.5, there is lateralization of or malignant hypertension with evidence of renin secretion. This, as well, seems to be pre- severe end-organ damage as a result. The pres- dictive of improvement following renal revascu- ence of hypertension in the setting of a unilat- larization. However, the failure to demonstrate erally shrunken kidney was also used as an lateralization does not reliably predict failure of indication for intervention. With respect to revascularization procedures. In addition, there renal insufficiency, the clinical criteria for inter- are unfortunately strict prerequisite guidelines vention were defined as unexplained worsening required prior to performance of this test. Anti- of renal function or a decrease in renal function hypertensive medications must be held for up to 225

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3 weeks prior to the test, which is not without However, the natural history of uncorrected clinical consequences. RAS is not benign. It has previously been docu- For these reasons, other physiological tests mented that 11% of patients with a greater than became more favorable. Initially, isotope renog- 60% stenosis of the renal artery progress to raphy was developed as a screening procedure occlusion within a 2-year period. As well, over for renovascular hypertension. The theory was 40% of patients with a critical stenosis of the that the underperfused kidney would have renal artery will have a decrease in glomerular delayed uptake and excretion of solute when filtration by greater than 25% with progressive compared to the normal, well-perfused con- deterioration in renal function being common tralateral kidney. Various nucleotides were uti- in this group of patients. lized; however, this test still yielded a high rate As a result of these findings, there have been of false-negative results. More recently, the numerous studies designed to evaluate medical results of this functional test have improved management for symptomatic RAS compared to through the use of the ACE inhibitor captopril. both open surgical repair as well as endovascu- Angiotensin II is elevated in patients with RAS, lar management. and this elevation leads to selective vasocon- Hunt and Strong (1973) orchestrated a com- striction of the efferent arterioles in an attempt parative analysis examining drug therapy com- to maintain glomerular filtration. The use of pared to operative therapy to treat symptomatic captopril blocks angiotensin II production, and RAS; 114 patients were in the medical treatment thus filtration drops precipitously. The finding arm and 100 patients were in the surgical treat- of a decrease in the uptake and excretion of the ment arm. The follow-up was over the course of tracer is more pronounced in patients after cap- 7 to 14 years. Overall, 84% of patients were alive topril in the setting of clinically significant RAS. in the surgical group compared to 66% alive in Through the use of captopril, this study has the group treated medically. Of those alive in the most recently demonstrated a 92% sensitivity surgical group, 93% were cured or significantly and a 94% specificity. improved, whereas of those patients in the medical treatment group, 21% subsequently required surgical intervention for uncontrolled Therapeutic Options hypertension. Another seven patients from that group continued to have uncontrolled hyper- The options for the treatment of symptomatic tension but were not taken to surgery. In addi- RAS include medical management utilizing tion, death was twice as common in the multiple antihypertensive medications, the medically treated group. These differences were < endovascular approach including angioplasty statistically significant (p .01) for both ather- with or without the placement of a stent,or open osclerotic and FMD lesions. This study demon- surgical management. strated that in patients with renovascular hypertension, there is a need to treat sympto- matic lesions surgically. Indeed, in this series, Medical Management of surgical intervention offered better sympto- Symptomatic Renal Artery Stenosis matic relief of hypertension, which translated to a lower incidence of end-organ damage. The medical management of symptomatic RAS Webster and colleagues (1998) performed the is accomplished using a variety of antihyper- first prospective randomized trial comparing tensive medications in an attempt to control the medical management with renal artery angio- hypertension. Control of the hypertension in plasty in 55 patients. All patients were hyper- itself is critical, as uncontrolled hypertension is tensive and showed evidence of ≥50% RAS on a major risk factor for myocardial infarction, angiography. They found that only patients with cerebrovascular accident, and chronic renal bilateral RAS demonstrated a significant insufficiency. Thus, the goals of medical man- decrease in blood pressure with angioplasty. agement of symptomatic RAS are to reduce the There was no significant improvement in renal blood pressure, to control cardiovascular risk excretory function. Otherwise, there was no sta- factors, and ultimately to prevent end-organ tistical difference between the two groups. This damage from sustained hypertension. study suggested that there might be a significant 226

VASCULAR SURGERY benefit to be derived from the endovascular However, in certain cases, endarterectomy may management of symptomatic RAS over medical still be feasible (Pak, 2002). management of these patients, which ultimately Although it is widely practiced at most insti- led to the validation of this therapeutic option. tutions, renal artery angioplasty and stenting is Based on the results of the above studies as a topic that is still the subject of modest debate. well as other smaller studies, it became clear There are only a few prospective randomized that intervention, either endovascular or open controlled trials that compare medical therapy, surgical, should play a significant role in the endovascular management, and open surgical treatment of symptomatic RAS. repair of symptomatic RAS. Weibull and associates (1993) prospectively and randomly assigned 58 patients with symp- Endovascular Repair of Renal tomatic RAS to either renal angioplasty or sur- Artery Stenosis gical renal revascularization. Percutaneous transluminal angioplasty (PTA) was initially In addition to open surgical repair for sympto- technically successful 83% of the time, whereas matic RAS, renal artery angioplasty with or surgical management was successful 97% of the without stenting offers a less invasive method to time. The primary patency rate after 2 years was correct the anatomical stenosis. Although still a 75% in the PTA group compared to 96% in the matter of great debate, it is clear that angio- surgical group. Secondary patency was 90% plasty with or without stenting may offer at least versus 97%, respectively, in the PTA and surgi- short-term improvement in blood pressure cal patients. Hypertension was improved in 90% and, in certain circumstances, renal function. after PTA and 86% following open surgical renal Although this option is especially appealing for revascularization, and improvement in renal patients, it is certainly necessary to further eval- function was seen in 83% and 72%, respectively. uate and better define what the role of endovas- The authors concluded that PTA is a reasonable cular management of symptomatic RAS should option when compared to surgical revascular- be through a multi-institutional randomized, ization. Indeed, the primary patency was lower prospective trial. in the endovascular group, but the secondary There is much debate regarding the need to patency was comparable. Patients treated with place a stent in the renal artery compared to angioplasty of RAS clearly require close surveil- angioplasty alone. Typically, renal artery angio- lance and often subsequent procedures to main- plasty alone is utilized for fibrodysplastic tain patency. lesions and lesions that do not involve the origin Martin and colleagues (2003), as well, have of the renal artery. However, as mentioned pre- demonstrated a 30% incidence of re-stenosis viously, RAS that is atherosclerotic in etiology is following initially technically successful renal often an extension of aortic plaque. For this artery angioplasty. This high incidence of re- reason, angioplasty alone is not as durable. It stenosis with respect to renal artery ostial has been demonstrated that atherosclerotic lesions is likely due to the fact that these lesions lesions of the renal artery seem to have lower represent extension of an aortic plaque. The rates of re-stenosis following angioplasty and idea of placing stents in the renal arteries as a placement of a stent for this reason. In addition, method of preventing re-stenosis was intro- it is clear that if there is a residual stenosis fol- duced by Palmaz in 1976, initially in animal lowing initial angioplasty or evidence of dissec- models and subsequently in humans. Currently, tion, a stent should be placed at that time. the indications for the placement of a stent in a There has been some concern that renal renal artery following renal artery angioplasty artery angioplasty and stenting may make oper- include substantial elastic recoil, resistance of ative intervention difficult or impossible sec- the plaque, or dissection. ondary to postangioplasty periarterial fibrosis. Bush and colleagues (2001) retrospectively This is especially true for transaortic renal examined the results of renal artery stenting in endarterectomy. In the case of a previously 73 consecutive patients over a 7-year period. In placed renal stent placement, renal artery this study, the majority of stents were placed bypass grafting to a site on the renal artery for residual stenosis following angioplasty or distal to the stent may be the best option. dissection. The technical success rate was 227

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89%, with one patient requiring thrombolytic cially useful because aortic cross-clamping may therapy for intrastent thrombus. The complica- be avoided. The conduits available for use tion rate was 9.1% with renal artery thrombo- include autologous vein grafts, synthetic polyte- sis, extravasation, and hematoma. In this study, trafluoroethylene (PTFE) and Dacron pros- the authors noted a significant decrease in both thetic grafts, and autologous hypogastric artery. systolic and diastolic blood pressures (p < .001) Nephrectomy, as well, may be considered in as well as a decrease in the number of medica- patients with unreconstructable renal disease tions required to treat the hypertension (p < with a nonfunctioning ipsilateral kidney. .01). Over the course of an average of 20 months’ The operative approach may be through a follow-up, serum creatinine levels decreased midline xiphoid to pubis incision, a supraum- by more than 20% in 22% of patients. It bilical transverse incision, an extended flank remained unchanged in 48% of patients and incision, or a subcostal incision. The midline deteriorated in 25% of patients. Of the 25% of approach is useful for atherosclerotic lesions as patients who had an increase in serum creati- well as lesions combined with aortic proce- nine, 12% eventually required hemodialysis. dures, whereas the subcostal or flank incisions Five of these patients had a preoperative creati- are efficacious for fibrodysplastic lesions or nine level over 4.0mg/dL. Over the course of splanchnorenal bypass. When combined with approximately 11 months’ follow-up, 10 patients mesenteric artery bypass grafting, the extended had evidence of re-stenosis in a total of 14 renal flank incision may be useful. Thromboen- arteries. Overall, this retrospective study estab- darterectomy may be easily accomplished via a lished the safety of endovascular management retroperitoneal trapdoor approach. with respect to these lesions as an alternative to With respect to exposure of the distal renal open surgical repair. artery, the left renal artery lies posterior to the Attempts to validate the endovascular man- left renal vein. The vein must be sufficiently agement of symptomatic RAS seem to be mobilized with division of the gonadal and beneficial, at least in the short term. This adrenal veins. The renal vein may be retracted method of treatment, although less invasive either cephalad or caudad to expose the renal than open surgical repair, appears not to be as artery.There is also a lumbar vein that enters the durable over the long term. This group of posterior aspect of the renal vein that may be patients needs close post–angioplasty and stent easily avulsed if not carefully identified and surveillance to detect re-stenosis and subse- ligated. Distal exposure of the renal artery is quent intervention to have results that are com- essential to clearly identify the extent of the parable to open surgical repair. However, this atheroma, and the renal artery should be dis- still remains an option that is feasible for the sected free distal to the atherosclerotic plaque. treatment of these lesions and attractive for the Silastic loops may be used for distal arterial patients. It is hoped that through the use of a control, as they are less traumatic compared to well-constructed trial, more data will be avail- metal clamps. able to formulate more solid conclusions on The aortic anastomosis is typically per- angioplasty and stenting of symptomatic renal formed utilizing an aortotomy that is two to artery stenosis. three times the diameter of the conduit. The anastomosis is usually placed on the anterolat- eral aspect of the aorta. It is essential to prevent Open Surgical Renal the graft from kinking. For right-sided revascu- Revascularization larizations, the aortorenal graft is typically placed in a retrocaval position, although this Open surgical repair or reconstruction of symp- must be individualized. With respect to left- tomatic renal artery lesions still remains the sided revascularizations, the graft is usually gold standard in treatment. Options for direct placed beneath the left renal vein. open surgical repair include aortorenal bypass, Subsequently, the renal anastomosis is com- reimplantation of the renal artery, and throm- pleted. This is typically anastomosed in an end- boendarterectomy. Indirect renal revasculariza- to-end fashion with spatulation of both the graft tion may be accomplished via splenorenal or and renal artery. Spatulated anastomoses are hepatorenal artery bypass. This option is espe- ovoid and less prone to the development of 228

VASCULAR SURGERY strictures. Intraoperative evaluation of blood Conclusions flow is typically accomplished using a direc- tional Doppler device. Intraoperative angiogra- phy is usually unnecessary; however, many Renovascular hypertension is an uncommon surgeons advocate baseline angiography prior cause of hypertension in the general population. to discharge to establish a baseline and to However, it may cause considerable morbidity confirm the adequacy of repair. with respect to end-organ damage from uncon- Hansen and colleagues (1992) retrospectively trolled hypertension as well as progression of reviewed the data on 200 patients who under- ischemic nephropathy. It appears as if duplex went open surgical renal revascularization over ultrasound is at least a reasonable screening tool a 54-month period. There was a mortality rate in patients suspected of having hypertension of 2.5% and only a 1.4% primary failure rate at that is renal in origin. However, there clearly 30 days. In this series, the hypertension was needs to be correlation between the anatomical cured in 21% of patients and improved in stenosis and the physiological effect. For this another 70%. Of the patients with ischemic purpose, there is not a clearly optimal test, nephropathy, 49% demonstrated an improve- although captopril renography seems to offer ment in glomerular filtration; 36% of these the best results at this time. patients remained stable and only 15% wors- Once diagnosed and found to be functionally ened. This study clearly demonstrates that open significant, there are several options for the surgical renal revascularization is a safe option treatment of RAS, including medical manage- that is successful in treating the underlying clin- ment, endovascular angioplasty with or without ical manifestations of the RAS in the majority of stent placement, or open surgical revasculariza- patients. tion. From the data that are available, it is Recently, Cherr and associates retrospectively clear that there is a patient population that reviewed the clinical outcome of 500 consecu- does benefit from revascularization, either tive patients with renovascular hypertension. endovascular or surgical. Surgical revascular- The perioperative mortality was 4.6% at 30 days. ization is more durable, and long-term success The hypertension was cured in 12%, improved has been previously demonstrated. Angioplasty in 73%, and unchanged in only 15%. With with or without stent placement is indeed less respect to ischemic nephropathy, 43% had an durable over the long-term; however, with close improvement in renal function, 47% were surveillance and secondary intervention, it may unchanged, and 10% became worse. Interest- offer results comparable with open surgical ingly, of the 43% of patients who demonstrated repair. an improvement in renal function, 28 patients Although there have been a multitude of were removed from dialysis dependence. These attempts to define which patients with sympto- data confirm the findings of Hansen and asso- matic RAS would benefit from renal revascular- ciates and once again demonstrate that open ization, both surgical and endovascular, there is surgical repair of severe, flow-limiting, sympto- still no clear consensus at the present time. matic RAS is efficacious in improving hyper- Recently, the American Heart Association tension and ischemic nephropathy in the released the guidelines for the reporting of renal majority of patients. It adds the point, however, artery revascularization in clinical trials. This that if there was a blood pressure cure or an document serves to clearly outline criteria and improvement in renal function, there was an definitions for randomized, controlled clinical association with dialysis-free survival. This has trials, which are needed to further dictate the a significant impact on patient lifestyle as well optimal management of symptomatic RAS. At as on health care dollars. this time, it is clear that certain patients do At this time, there is significant controversy benefit from restoration of blood flow to the regarding the optimal treatment in patients kidney, but a multicenter, prospective, random- with symptomatic RAS. It is important that a ized, controlled study will be better able to multicenter, prospective, randomized clinical define which patients benefit from surgical trial be organized in an effort to further define repair compared to endovascular management the best possible treatment options for these and which patients, if any, should merely be patients. treated medically. 229

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Rundback JH, Sacks D, Kent KC, et al. (2002) J Vasc Intervent References Radiol 13:959–74. Simon N, Franklin SS, Bleifer KH, Maxwell MH. (1972) Barrett BJ, Carlisle EJ. (1993) Radiology 188:171–8. JAMA 220:1209–18. Bush RL, Najibi S, MacDonald MJ, et al. (2001) J Vasc Surg Webster J, Marshall F,Abdalla M, et al. (1998) J Hum Hyper- 33:1041–9. tens 12:329–35. Goldblatt H. (1934) J Exp Med 59:347. Weibull H, Bergqvist D, Bergentz SE, Jonsson K, Hulthen L, Hunt JC, Strong CG. (1973) Am J Cardiol 32:562–74. Manhem P. (1993) J Vasc Surg 18:841–50; discussion Martin LG, Rundback JH, Sacks D, et al. (2003) J Vasc Interv 850–2. Radiol 14:5297–310. Zierler RE, Bergelin RO, Isaacson JA, Strandness DE Jr. Pak LK, Kerlan RK, Mully TW, Messina LM. (2002) J Vasc (1994) J Vasc Surg 19:250–7; discussion 257–8. Surg 35:808–10. Radermacher J, Chavan A, Bleck J, et al. (2001) N Engl J Med 344:410–17. 19 Visceral Ischemic Syndromes George Geroulakos, Peter A. Robless, and William L. Smead

The disorders of the visceral circulation are and aggressive management are essential. infrequent mainly because of the very extensive However, the relative rarity of this condition, and efficient collateral system connecting the along with the nonspecific physical findings celiac, superior mesenteric, and inferior mesen- makes early diagnosis difficult and is often teric arteries. However, there is a lot of interest delayed. Furthermore, patients with AMI are in the optimal management of these conditions, often elderly, malnourished, and have signi- because of their catastrophic outcomes that are ficant comorbidity that increases the risk of usually associated with a high morbidity and major surgical intervention. mortality. Over the last two decades there has The most common causes of AMI are supe- been a greater awareness of these conditions, rior mesenteric artery embolization (50%) or which was followed by the introduction of new thrombosis (25%), nonocclusive mesenteric diagnostic and therapeutic techniques such as ischemia (20%), and acute mesenteric venous duplex ultrasound,computed tomography (CT), thrombosis (5%). Rarer causes include vas- magnetic resonance angiography (MRA), and culitis, fibromuscular dysplasia, dissection, angioplasty/stenting. trauma, and mesenteric aneurysm rupture or Visceral ischemic syndromes can be classified thrombosis. as acute or chronic. Acute ischemic syndromes are the result of embolic or thrombotic occlu- Pathophysiology sion of a visceral branch of the infradiaphrag- matic aorta. In addition, it could be the result of Two thirds of mesenteric blood flow supplies mesenteric venous thrombosis. Chronic visceral the gut mucosa. Splanchnic autoregulation fails ischemia is usually caused by stenotic or occlu- when perfusion pressure falls below 40mmHg, sive atherosclerotic lesions involving two or and prolonged gut ischemia results in anaerobic more visceral vessels. metabolism. The extent of injury is related to the duration and the anatomical extent of mesenteric ischemia. At the cellular level, Acute Mesenteric Ischemia adenosine triphosphate (ATP) is depleted with a buildup of catabolic products and lactate. Acute mesenteric ischemia (AMI) is a life- Mucosal and vascular permeability increases threatening condition seen in 1 per 1000 hospi- and tissue injury occurs. Hemorrhagic necrosis tal admissions with mortality rates ranging follows with mucosal sloughing, bowel wall between 60% and 100% despite advances in edema, and intestinal hemorrhage (Table 19.1). operative technique and perioperative manage- The bowel wall becomes permeable to gut bac- ment (Bradbury et al., 1995). Early diagnosis teria once the mucosa is shed. Peritonitis results

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Table 19.1. Pathophysiology of mesenteric ischemia rotic stenosis progressing to occlusion. This Mucosa—villous sloughing usually occurs at the origin of the vessel. Other Increased capillary permeability—Edema causes include systemic vasculitic and pro- Submucosal hemorrhage thrombotic syndromes. Less common causes Transmural necrosis include aortic and visceral artery aneurysms or dissection. Some patients may describe pro- dromal symptoms compatible with chronic mesenteric ischemia. These patients often have from transudation of microflora across the coexisting multilevel atherosclerotic disease. intestinal wall. Septicemia develops as the Unlike acute mesenteric embolism, the onset of organisms enter the portal circulation. Massive pain is often gradual, with nonspecific central fluid shifts into the bowel wall and peritoneum abdominal pain. The extent of infarction usually follow,resulting in hemoconcentration,oliguria, involves the duodenum to the transverse colon and hypotension. Serum levels of lactate dehy- and is typically more extensive than that seen drogenase (LDH), serum glutamic oxaloacetic with acute embolism. transaminase (SGOT), and creatine kinase (CK) become markedly elevated with the death of Nonocclusive Mesenteric Ischemia intestinal cells. Ischemia reperfusion injury due to free Nonocclusive mesenteric ischemia (NOMI) radical production through the xanthine develops in patients with low-cardiac-output oxidase pathway may result from subsequent states, especially in the presence of digoxin or reperfusion of the acutely ischemic gut. There is vasoconstrictors. Secondary mesenteric vaso- a high mortality rate from the ensuing multior- constriction results in segmental vasospasm of gan dysfunction syndrome. the secondary and tertiary branches of the SMA. It is not caused by underlying atherosclerosis or venous obstruction. Causes of low-flow states Acute Mesenteric Embolism include cardiac failure, shock, and hypovolemia. The main presenting symptom is usually the The use of vasoconstricting agents that affect sudden onset of severe central abdominal pain. the splanchnic circulation such as digoxin, The severity of the pain is usually out of pro- cathecholamines, angiotensin II, vasopressin, portion to the physical findings. This may be beta-blockers, and cocaine has been associated accompanied by vomiting or diarrhea. with NOMI. Mesenteric emboli can originate from the heart or the supradiaphragmatic aorta and most Diagnosis frequently occur in patients with cardiac arry- thmias, valvular disease, or following myocar- Acute mesenteric ischemia presents classically dial infarction. If the embolus disintegrates and with acute onset of abdominal pain out of pro- travels distally, the resulting ischemia may be portion to the physical findings.Central abdom- patchy, typically affecting the duodenum, prox- inal pain occurs as a result of mid-gut ischemia imal jejunum,and colon.The majority of emboli and spasm. Gastrointestinal emptying, with lodge in the superior mesenteric artery (SMA) emesis and bloody diarrhea may occur. Labora- distal to the origin of the middle colic artery, tory findings including leukocytosis, acidosis, often sparing the proximal jejunum and ascend- hyperkalemia, raised hematocrit, LDH, SGOT, ing/transverse colon. Owing to the lack of ade- and CK occur later. However, no single labora- quate collaterals, this may lead to reactive tory investigation or combination of tests has vasoconstriction, thereby reducing existing col- proved to be sensitive or specific enough to lateral blood flow and increasing the ischemic enable the early diagnosis of AMI. injury. Early recognition of AMI is crucial, as bowel necrosis develops in many patients by the time Mesenteric Artery Thrombosis of surgery and investigations should not pro- duce unnecessary delays in revascularization. Thrombosis of the SMA or celiac axis occurs Plain abdominal x-rays may show nonspecific as a result of underlying mesenteric atheroscle- findings of intestinal dilatation, gasless abdo- 233

VISCERAL ISCHEMIC SYNDROMES men, or other signs of ileus. Occasionally mural Treatment “thumb printing” is caused by submucosal edema or hemorrhage. Pneumoperitoneum or Regardless of the etiology of the AMI, the goals portal vein pneumatosis may be seen in of surgical treatment are to reestablish good advanced cases with transmural infarction. pulsatile flow to the SMA, to restore adequate Ultrasonography in patients with AMI may blood flow to the ischemic but viable gut, and to reveal a thickening of the bowel wall, signs of resect the necrotic bowel. Adequate volume ileus with distended bowel loops, intraperi- resuscitation and correction of acid base and toneal fluid, or air in the portal vein. Ultra- electrolyte imbalance must also be undertaken. sonography is also helpful in excluding other Cardiac output has to be optimized, and any causes of an acute abdomen. arrhythmias treated. Broad-spectrum antibi- Ultrasound and plain x-rays are not very otics are given if signs of peritonitis are present. specific in diagnosing AMI and other imaging The single factor in improving the results modalities such as CT, MRA, and contrast of surgical treatment of acute mesenteric angiography play a major role in the diagnosis. insufficiency has been the addition of tran- Computed tomography angiography is sen- scatheter intraarterial vasodilator infusion peri- sitive for the diagnosis of mesenteric occlusion operatively (Boley et al., 1981). or bowel ischemia. Computed tomography The decision to undertake second-look scanning also facilitates the identification of laparotomy is made at the time of the initial nonvascular causes of acute abdominal pain. laparotomy. It allows the reassessment of bowel Computed tomography angiography with three- viability and to decide if further bowel resection dimensional reconstruction may facilitate iden- is required. Bowel viability can be assessed by tification of vascular anatomy and pathology physical examination, handheld Doppler scan with good enough detail for diagnosis and oper- examination, and intravenous injection of ative planning (Fock et al., 1994). fluorescein (Ballard et al., 1993). Differentiation of the three forms of mesen- teric arterial occlusion can be done with aor- tography and it facilitates planning of Acute Mesenteric Artery Embolism treatment. Selective mesenteric angiography Surgical revascularization in the presence of an remains the most reliable and definitive diag- embolism is performed with balloon embolec- nositic tool for AMI. Endovascular interven- tomy usually with patch angioplasty of the SMA. tions or catheter-directed vasodilator therapy Patients with chronic proximal occlusion or can be started immediately after angiography stenosis undergo revascularization with bypass (Park et al., 2002). grafting. Autogenous vein is the graft material Thrombotic occlusion of the SMA produces a of choice if resection of necrotic bowel is nec- sudden cut-off at the vessel origin or within 1 to essary. Resection of the infarcted bowel is per- 2cm of the SMA trunk. Extensive collaterals in formed following revascularization. the distal SMA indicate a chronic occlusion. Mesenteric arterial emboli produce a sharp, rounded filling defect with a typical meniscus Acute Mesenteric Artery Thrombosis sign on angiography.Vasospasm may be present with mesenteric thrombosis or embolism. The thrombotic process occurs in a severely ath- Angiographic criteria for NOMI include a erosclerotic proximal SMA. Therefore, these diffuse narrowing of the SMA and its branches, patients require placement of a bypass graft to alternating areas of narrowing and dilatation of the SMA distal to the occlusive segment. Ante- the SMA branches (string of sausages sign), grade or retrograde bypass may be performed spasm of the peripheral vascular arcades, depending on anatomical considerations or impaired filling of the intramural vessels, and a according to surgeon preference. sluggish flow with reflux of contrast during Thrombolytic therapy is a potential consider- selective SMA injection. Increased vessel diam- ation in patients with acute thrombosis and no eter following papaverine infusion and the clinical signs of peritonitis. Successful lysis absence of atherosclerotic disease on angiogra- returns the mesenteric circulation to its chronic, phy supports the diagnosis of AMI. stable state. Subsequent operative revasculari- 234

VASCULAR SURGERY zation or balloon angioplasty of the stenotic Investigations vessel can be undertaken electively. How- ever, this does not allow inspection for bowel Gastrointestinal contrast studies, endoscopy, viability following reperfusion and may delay and computed tomography are not essential to operative revascularization if thrombolysis is the diagnosis but are important in eliminating unsuccessful. Thrombolysis in AMI therefore other sources of abdominal discomfort. should be reserved for selected patients (Park Microulceration of the gastric mucosa and atyp- et al., 2002). ical colonic mucosa ulceration are uncommon endoscopic findings. Duplex ultrasound examination of the celiac Nonocclusive Mesenteric Ischemia and the superior mesenteric artery origin can be successfully obtained in 80% to 95% of the The treatment of NOMI is primarily nonsurgi- cases, and in these it is a reliable screening test cal. A metabolic cause of the problem should be for chronic visceral ischemia. To obtain optimal identified and corrected. The SMA is selectively visualization of the celiac and superior mesen- catheterized, and vasodilating agents such as teric arteries, patients should be on a clear papaverine (or tolazoline hydrochloride) are liquid diet on the day before the examination administered. Resection of nonviable bowel and should refrain from oral intake for 6 hours may be required (Park et al., 2002). before the study. Lateral views of biplane aor- tography remains the primary diagnostic modality in demonstrating visceral occlusive Chronic Visceral Ischemia lesions compatible with the diagnosis. In a typical patient there is involvement of two or all Clinical Presentation three visceral arteries. Aortography also reveals the meandering mesenteric artery (arch of The most common pattern of symptoms is Riolan or arch of Treves), a large collateral tor- chronic abdominal pain that is associated with tuous vessel of uniform caliber residing in the involuntary weight loss. The pain is usually epi- left upper quadrant of the abdomen. It connects gastric, dull, or colic. The patient experiences the middle colic artery with the patent trunk of the pain 15 to 30 minutes after eating, and it the inferior mesenteric artery. lasts for 1 to 3 hours before disappearing. The pain becomes so severe that soon the patient develops fear of food and limits the oral intake. Treatment This results in a pronounced weight loss. Angioplasty Absence of weight loss may put in doubt the diagnosis of chronic visceral ischemia. Other Mesenteric percutaneous transluminal angio- gastrointestinal complaints may include diar- plasty (PTA) is a valuable treatment option in rhea, nausea or vomiting, and constipation. The patients with chronic visceral ischemia who are most typical feature of the clinical presentation considered high operative risk. The initial tech- is that the symptoms are atypical.We and others nical success rate is good, with the majority of have shown that the majority of the patients patients having symptomatic improvement and affected are women in their sixth decade of life. continuous relief of symptoms at short-term The reasons for this sex predilection remain follow-up. However, long-term patency results undetermined. On examination, the patient are unknown. Allen et al. (1996) presented a looks emaciated, mimicking a patient with series of 19 patients treated by PTA. The only advanced malignant disease. These is often an technical failure resulted in mesenteric artery epigasric bruit present. dissection, thrombosis, bowel infarction, and a Untreated patients with symptoms of chronic fatal outcome. Complete symptomatic relief was visceral ischemia are at an increased risk of attained in 15 patients. Recurrent symptoms death from complications of acute visceral developed in three patients (20%) at a mean ischemia. In a large series of patients presenting interval of 28 months. Percutaneous translumi- with acute mesenteric ischemia over a period of nal angioplasty may also be used for the man- 10 years, 43% had prior chronic symptoms. agement of recurrent symptoms following the 235

VISCERAL ISCHEMIC SYNDROMES development of a stenosis in the aortomesen- endarterectomy facilitates direct removal of the teric bypass. aortic plaques. Duplex scanning should be routinely used at the end of the procedure to Surgery document the technical result at the distal end point of the endarterectomy in the mesenteric/ A variety of techniques have been developed celiac artery. A comparison of antegrade bypass to correct atherosclerotic obstruction of the (n =004 26) and transaortic endarterectomy major visceral branches of the thoracic aorta. (n = 48) showed the same incidence of periop- Techniques of revascularization include tran- erative mortality and 5-year recurrence-free section of the mesenteric artery and reimplan- survival for both groups (Cunningham et al., tation on the aorta, bypass grafting, and 1991). thromboendarterectomy. There is no consensus regarding the best surgical approach for the treatment of chronic visceral ischemia. Bypass grafting is the most common type of visceral Mesenteric Venous revascularization performed today. It provides Thrombosis immediate restoration of flow and may origi- nate from several different locations that Mesenteric venous thrombosis is a rare but include the suprarenal aorta (antegrade recon- potentially lethal form of intestinal ischemia struction) or the infrarenal aorta and the that accounts for 5% to 15% of all cases of common iliac arteries (retrograde reconstruc- mesenteric vascular events. Improved survival tion). The distal thoracic aorta is usually free of depends on early recognition and appropriate atherosclerosis and is an excellent origin of a treatment of this entity. short bypass placed in the direction of normal flow. This design eliminates the possibility of kinking and thrombosis by compression or Etiology traction from the overlying mesentery, which may be observed with retrograde grafts. The Low-flow states in the mesenteric venous circu- distal thoracic aorta may be approached from lation that may be produced by liver cirrhosis, the abdomen or via a thoracoabdominal inci- portal hypertension, and congestive heart sion. The retrograde bypass has the advantage failure could lead to mesenteric venous throm- that its origin is in a more familiar territory, bosis. Intraabdominal infections from organs but it is more commonly affected by atheroscle- that drain to the mesenteric venous system such rotic or aneurysmal disease. Park et al. (2002), as appendicitis, diverticulitis, pelvic abscess, in a large series of 98 reconstructions for and pancreatitis can be associated with mesen- chronic visceral ischemia, reported a 5-year teric venous thrombosis. Other conditions that symptom-free survival of 92%. The rate of may predispose to mesenteric venous thrombo- recurrence was unaffected by the number of sis include hypercoagulable states associated vessels revascularized or the orientation of the with malignancy,oral contraceptives, and recent bypass. In contrast, others have reported that operations, particularly splenectomy followed revascularization of as many visceral vessels by thrombocytosis. Thrombophilia is common as possible is important in reducing the risk in this group of patients. In a series of 31 of recurrent intestinal ischemic symptoms patients, 13 (42%) were diagnosed to have a (Rheudasil et al., 1988). Thus the number of hypercoagulable state. Twelve patients were vessels that need to be revascularized remains a found to have protein C, protein S, or antithrom- controversial issue. bin III deficiency. A single patient had activated Thromboendarterectomy has been used by a protein C resistance. Six patients had prior small number of groups with excellent results. thrombotic episodes, including deep venous The aorta is approached via medial visceral thrombosis (n = 5) or arterial thrombosis (n = rotation. For the majority of ostial stenoses, a 1). Four patients had a history of cancer, and five “trapdoor” arteriotomy is made around the patients had previously undergone a splenec- celiac and superior mesenteric arteries as they tomy (mean platelet count 487,000) (Morasch emerge from the aortic wall. A retrograde et al., 2001). 236

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Clinical Presentation and intravenous heparin. Close clinical and hemodynamic monitoring is indicated, prefer- The most common presenting symptom is ably in an intensive care unit. If peritoneal signs abdominal pain. The pain is constant, colicky, are present, a laparotomy should be performed and poorly localized. Often the complaints of and the infarcted bowel should be resected. An abdominal pain are out of proportion to the ileostomy should be considered if there is exten- clinical findings. Other symptoms include vom- sion of the macroscopic involvement at the iting, diarrhea, and constipation. In a series of resection margins. The macroscopic features of patients with mesenteric venous thrombosis, the affected part of the bowel are striking, and upper and lower gastrointestinal bleeding consist of a dark red coloration and thickening occurred in 10% and 19% of the patients, of the bowel. It is often difficult to distinguish respectively. Physical findings in patients who viable from nonviable bowel. In a recent series had gradual onset of abdominal symptoms may 82% of patients who underwent bowel resection reveal low-grade pyrexia, abdominal distention, (about 100cm length) did not have transmural increased bowel sounds, and generalized necrosis. Bowel viability assessment by direct abdominal tenderness. When the pain is local- inspection may be improved by Doppler ultra- ized, it may be located in either the upper or sound techniques or fluorescein examination lower quadrants of the abdomen. under a Wood’s lamp. Several case reports have Peritoneal signs such as guarding and been published indicating that thrombolysis rebound are present when infarction of the may be a useful treatment option for patients bowel has occurred. with no signs of peritonitis. Antegrade transar- terial thrombolysis via the superior mesenteric Investigations artery has been effective in a small number of cases in lysing the thrombus and providing Plain abdominal films are abnormal but not good symptomatic relief (Antoch, 2001). Post- specific in the majority of the patients. Edema- operatively, patients should be anticoagulated to tous and dilated small bowel loops are the most prevent recurrent episodes of thrombosis. The common finding. duration of anticoagulation is determined by Contrast-enhanced CT scanning is the most the expected duration of the predisposing sensitive tool in detecting acute mesenteric factors. venous thrombosis. The presence of a mesen- teric venous filling defect is diagnostic of this condition. Other CT findings include free fluid; an enlarged, dilated superior mesenteric vein; References mesenteric edema or stranding; bowel wall Allen RC, Martin GH, Rees CR, et al. (1996) J Vasc Surg thickening or edema; and dilated small bowel 24:415–21; discussion 421–3. loops. Selective mesenteric angiography may Antoch G, Taleb N,Hansen D, Stock W.(2001) Vasc Endovasc show intense spasm of the arterial branches Surg 20:471–2. supplying the involved part of the bowel, pro- Ballard JL, Stone WM, Hallett JW, Pairolero PC, Cherry KJ. longed opacification of the thickened bowel (1993) Am Surg 59:309–11. Boley SJ, Feinstein FR, Sammartano R, Brandt LJ, Sprayre- wall, contrast extravasation into the lumen of gen S. (1981) Surg Gynecol 153:561–9. the bowel,visualization of the venous thrombus, Bradbury AW, Brittenden J, McBride K, Ruckley CV. (1995) or nonvisualization of the venous phase. Cur- Br J Surg 82:1446–59. rently, angiography is not recommended as the Cunningham CG, Reilly LM, Rapp JH, Schneider PA, Stoney RJ. (1991) Ann Surg 214:276–87; discussion 287–8. initial investigation. Fock CM, Kullnig P, Ranner G, Beaufort-Spontin F, Schmidt F. (1994) Eur J Radiol 18:12–14. Treatment Morasch MD, Ebaugh JL, Chiou AC, Matsumura JS, Pearce WH, Yao JS. (2001) J Vasc Surg 34:680–4. Park WM, Gloviczki P,Cherry KJ Jr, et al. (2002) J Vasc Surg Patients with mesenteric venous thrombosis 35:445–52. and no signs of peritonitis are treated with fluid Rheudasil JM,Stewart MT,Schellack JV,Smith RB 3rd,Salam resuscitation, prophylactic antibiotic therapy, AA, Perdue GD. (1988) J Vasc Surg 8:495–500. 20 Endovascular Approaches and Techniques Steven M. Thomas, Kong T. Tan, and Mark F. Fillinger

This last chapter describes the equipment com- rial injury is the 20- or 22-gauge needle typically monly used during endovascular procedures; used as part of a “micropuncture” set. The some of the commonly used endovascular tech- micropuncture technique uses a 0.014- or 0.018- niques, beginning with arterial access tech- inch guidewire and standard Seldinger tech- nique; and the endovascular interventions for nique to introduce a short 4-French sheath, arterial occlusive disease and aneurysmal which is then used to place the typical 0.035- disease. Embolotherapy is also discussed. inch guidewire. Equipment for Access, Wires Guidewires are integral to successful catheteri- Angiography, and zation; they support the catheter and allow the Vascular Intervention catheter to be steered to its intended location. Guidewires come in many diameters and Needles lengths, and degrees of stiffness, slipperiness, and steerability. All wires have a softer, more In general terms, there are two types of needles flexible, curved, or “floppy” leading end to min- available for obtaining vascular access: one-part imize damage to the vessel as it is advanced, and two-part. The one-part needle has a sharp though the length of the flexible segment may cutting bevel, whereas the two-part needle has vary.This is because a long flexible segment may a sharp inner stylet with a blunt outer needle. be useful if a vessel is extremely tortuous, or a The two-part needle is preferred by many for very short flexible segment may be needed to vascular access at the femoral artery, because it allow maximum support for an advancing reduces the risk of vascular damage at the access catheter or sheath. point, either due to movement of the needle tip or passage of the guidewire into the subintimal Diameter plane (see Access Technique, below). The most commonly used needle calibers are 18 and 19 Most standard guidewires are 0.035 inch in Stubs needle gauge (18 being the larger and diameter, though some very stiff wires are 0.038 equivalent to about 1.25mm in outer diameter). inch in diameter. It is important to ensure that For most purposes the 19-gauge needle suffices, the wire used is compatible with the lumen though it does not accommodate an 0.038-inch- diameter of the catheter to be placed over it. If diameter guidewire if required. A newer variant small-caliber catheters are used, small-diameter of the one-part needle designed to reduce arte- wires such as 0.014 or 0.018 inch are required.

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However, many of these wires do not have the Table 20.1. Variation in guidewire stiffness same stiffness as larger diameter wires, and Floppy hence may kink or result in poor tracking of the Bentson catheter. If a kink is produced, it is usually very Movable core difficult to pass a catheter over the wire, and a Standard J or straight new wire is required. The hydrophilic Terumo Hydrophilic (Terumo, Leuven, Belgium) guidewire has a More supportive nitinol core and is difficult to kink. Heavy duty J or straight Stiff hydrophilic Wholey Length Stiff The usual length of guidewire required is about Amplatz super stiff Amplatz extra stiff 150cm, and this is adequate for most diagnostic TAD imaging. However, in some circumstances Flexfinder longer wires are required, usually ranging from Very stiff 200 to 300cm. This is particularly the case in a Meier peripheral location, where the catheter has to be Lunderquist changed, or a guiding catheter, angioplasty balloon, or stent has to be introduced. When using monorail balloon catheters or stents for nearly frictionless. They are very useful for intervention, this is usually less of a problem negotiating tortuous vessels and crossing compared to systems that are fully over the wire. stenoses and occlusions. They can be difficult to This is because in a monorail system the wire handle because when slippery, the wire may slip passes through the wire guide for only about 30 back through the operators hands during cm from the tip of the catheter or device, rather catheter exchanges, and if allowed to become than through the whole length of the catheter or dry, can stick to the operator’s gloves and are device as occurs in a fully over-the-wire system. then easily pulled out inadvertently.These prob- Aortic stent-graft interventions also tend to lems can be minimized by keeping hydrophilic require long (260cm) guidewires due to the wires moist, handling the wires with a damp length of the delivery system for most aortic gauze to allow slightly more friction than a stent grafts. However, systems tend to be manu- glove, using a “torque device” when manipulat- facturer-specific, as some newer aortic stent- ing the wire, and using caution when moving graft systems require only 180-cm guidewires. the wire in or out of the patient. Stiffness Steerability The degree of guidewire stiffness varies consid- J erably (Table 20.1). It is generally easier to track A completely straight wire and a wire have a catheter or device over a stiffer guidewire; little or no inherent steerability. A straight wire, however, a very stiff guidewire may be more to which a curve has been introduced, can be difficult to manipulate into a vessel origin or directed using the curve, and this is enhanced if through a diseased vessel. Exchanging wires is a directional catheter is also used. Many wires often necessary for different parts of a proce- have tips that can be deformed into a curve or J dure, but a stiff wire should always be placed even into a if required. Some hydrophilic wires through a catheter that has been positioned have a preformed curve or angle, and if the core using a more conventional wire to prevent is made of nitinol (an elastic nickel-titanium damage to the vessel during advancement of the alloy with “memory”), this cannot be changed. stiff wire. This gives more torque control and makes the wire very steerable. Slipperiness Catheters Some wires (e.g., Terumo Glidewire or Cook Nimble guidewire), have a hydrophilic coating There are a plethora of catheters available, to be that, once lubricated, becomes very slippery and placed over the guidewire to facilitate arteriog- 239

ENDOVASCULAR APPROACHES AND TECHNIQUES raphy, selective entry to branch vessels, device nal mammary or renal double-curve catheters delivery, and so on. The size of catheter is are designed to aid catheterization of particular denoted using the French (F) system, which vessels. In practice, most angiographers prefer describes the outer circumference (external to have a range of catheters available and some- diameter of 3F = 1mm external diameter). times many may be used to achieve a difficult Smaller caliber catheters have the advantage selective arterial position. Probably the six that the access puncture site can be kept small, most commonly used selective catheters are although the turning ability or torque control is Berenstein (or similar Kumpe), Cobra, often compromised. For nonselective angio- Sidewinder, Headhunter, Sos Omni, and Multi- grams this is not usually a problem, and 3F or purpose. Catheters such as the Sidewinder and 4F catheters can be used, but if a selective Cobra come in a range of sizes designated 1 to catheterization is required, then larger caliber 3 dependent on the degree of catheter curve or catheters may be required. loop. These are useful for varying the degree of It must be remembered that catheters are angulation at the catheter tip, and the ease of thrombogenic to some extent, and should manipulation as the diameter and tortuosity always be regularly flushed with heparinized varies substantially in large vessels. When using saline while in the patient. In the case of guide a Sidewinder catheter in the aorta, if the loop is catheters, this is often best achieved using a bag too large, the catheter tip will be held away from of heparinized saline (using a pressure bag) the aortic wall and will not engage branch connected via a side arm. vessels. This may be modified by introducing a Most catheters are reasonably radiopaque, guidewire into the apex of the catheter curve, though hydrophilic-coated “glide catheters” but this often means that a smaller Sidewinder and smaller caliber catheters can be relatively or a Sos Omni catheter should be used instead. radiolucent. Some catheters have radiopaque Most of these catheters can be used as soon material added to them toward the tip, or a as the wire is removed from them, and will radiopaque band at the tip to enhance visibility. engage side branches if advanced or retracted. The Sidewinder and smaller Sos-Omni catheters Catheter Types need to be re-formed so that the reverse curve of the catheter can be used to engage side Most catheters can be divided into two main branch vessels. The Sos Omni, being of a smaller groups: nonselective and selective. curve than the Sidewinder catheters, can usually be re-formed in the aorta. The Sidewinder Nonselective Catheters catheter usually has to be re-formed using a variety of techniques. The simplest and safest is These are used to inject large volumes of con- to place a guidewire over the iliac bifurcation trast at high rates into large vessels. They have using a pigtail catheter and re-form the multiple side-holes to allow high injection rates sidewinder in the lower aorta. If this is not pos- and reduce the risk of subintimal injection by sible, it can usually be easily reformed in the the end-hole jet of contrast. The most com- aortic arch by twisting and advancing the monly used nonselective catheter is the pigtail unformed catheter. Once formed, the catheter is catheter, the workhorse of diagnostic angiogra- pulled back to engage the origins of arterial side phy. If the vessel is too small to accommodate branches. the pigtail loop, a straight multi–side-hole When choosing a catheter, it is important first catheter can usually be used instead. to select the appropriate gantry angle to view the origin of the vessel and its “true” degree of Selective Catheters angulation relative to the parent vessel. The angle of origin of the vessel being catheterized These are shaped catheters that have directional often dictates which catheter is most likely to properties that aid selective catheterization of successfully engage the arterial origin, so, for side branch vessels. Some, such as the Multi- example, vessels that are angled back toward the purpose, Cobra, Berenstein, and Sidewinder site of access are often best approached with a catheters, can be used for a variety of selective Sidewinder or similar catheter. There are also examinations, whereas others such as the inter- catheters that have hydrophilic coatings, and 240

VASCULAR SURGERY these are often very useful for tracking a catheters come in a variety of lengths and catheter to peripheral locations, particularly for shapes to aid introduction into the vessel embolization. ostium, allowing conventional catheters to be introduced through them for more distal Microcatheters catheterization. Guiding catheters can perform a similar role to sheaths, but they do not usually These are coaxial catheters that are only 2F to have an integral hemostatic valve, and their 3F in diameter that will pass through the 0.035- internal lumen is smaller. Thus, in some cases a or 0.038-inch lumen of the selective catheters guiding catheter may be placed within a short mentioned above. They were originally devel- sheath with a hemostatic valve, or used in com- oped for cerebral catheterization and inter- bination with a Y adapter and a Tuohy-Borst vention, but can be useful for superselec- valve for hemostasis. tive catheterization of visceral or peripheral vascular beds, particularly for embolization procedures. Commonly Used Medications Sheaths When performing vascular interventions, a number of medications are frequently required. Sheaths are used to establish a secure pathway Examples in a number of broad groups are pro- from the skin to the arterial lumen. This allows vided, but this is not a comprehensive descrip- catheters and devices, such as balloons and tion. Practioners should be familiar with local stents, to be exchanged in an atraumatic guidelines for medication use, and if in doubt manner. The sheath is a plastic tube with a should consult standard sources to check hemostatic valve and an attached side arm to dosages and interactions. allow flushing. The size designation of the sheath refers to the size of catheter that will pass Local Anesthetics through it (i.e., the internal diameter). Hence, a 7F sheath allows the passage of a 7F catheter or Local anesthetic is used for nearly all diagnos- device. As a result the external diameter of any tic and interventional procedures. The most sheath is approximately 1F larger than its desig- commonly used agent is lignocaine hydrochlo- nated size for smaller sheath sizes, and 2F to 3F ride (lidocaine in the United States). It has a low larger when the sheath size is in the 12F to 25F incidence of side effects when used as a local range. The thickness of the sheath is also some- anesthetic, but a total dose of 200mg (20mL of what dependent on its length and intended 1% solution) should not be exceeded, as over- application, generally thicker for longer sheaths dosage may lead to central nervous and cardio- intended to pass stents or stent grafts through vascular system toxicity. Alternative agents tortuous arteries. If the puncture is at a steep are prilocaine hydrochloride or bupivacaine angle or in obese patients, the smaller sheaths hydrochloride, which are longer acting and may may kink, particularly with an antegrade punc- be useful in certain circumstances. Depending ture. There are reinforced sheaths that are resist- on the agent, some adjustments may be advised ant to kinking, but they have an external for renal impairment, primarily related to diameter 1F to 2F greater than standard sheaths. metabolites that are renally excreted, or hepatic Most sheaths are short, but longer sheaths impairment. For any of these agents, direct and guiding catheters can be useful during intraarterial or intravenous injection should be interventional procedures to provide stability to avoided, due to risk of seizure and other poten- aid selective catheterization and delivery of bal- tial immediate systemic effects. loons or stents. Guiding catheters are larger than standard catheters, often 6F to 7F, because Heparin they are designed to work with a standard catheter within. Because they are catheters, it is Heparin is added to saline flushes and used rou- important to remember that their size is desig- tinely in higher doses during interventional nated by the external diameter, unlike a sheath, procedures. In both cases it helps prevent peri- despite similarities in appearance. Guiding catheter or vessel thrombosis during the pro- 241

ENDOVASCULAR APPROACHES AND TECHNIQUES cedure. For flushes, it is used in a dose of Sedation/Analgesia about 5000IU per liter of normal saline. For interventional procedures, doses of between Sedation is rarely required for vascular proce- 3000 and 5000IU are given depending on the dures, short of aortic stent grafts. Patients with size of the patient and the proposed length of limb ischemia should have their pain adequately the procedure.For aortic stent-graft procedures, controlled prior to investigation, as patients in the sheaths may be totally occlusive, and sys- severe pain can rarely lie still for prolonged temic heparinization is commonly used. Sys- periods. If sedation is required, small doses of temic heparinization is also common in carotid short-acting benzodiazepines such as midazo- stent procedures, due to the risk of emboli and lam (2 to 10mg IV) are preferred, with the aim to prevent thrombosis related to distal protec- being to relax, not anesthetize, an agitated tion devices. As the half-life of heparin is 45 to patient. If anesthesia is produced, an anesthetist 60 minutes, further doses should be considered must be in control of it, but if oversedation does if a procedure is prolonged. During longer occur, the effects of the benzodiazepine can be cases or for systemic heparinization, dosing reversed (temporarily) with flumazenil (200mg may be based on the activated clotting time over 15s and then 100mg every 60s up to a total (ACT),with target levels in the 250 to 300s range dose of 1mg). If analgesia does become neces- depending on the procedure, the degree of vas- sary, opiates such as morphine or pethidine (25 cular occlusion by devices, and the throm- to 100mg) can be given IV, or an appropriate boembolic risk. oral opiate can be given, though the onset of action may be considerably delayed. In all cases Vasodilators with analgesia and sedation, IV administration is preferred, as IM absorption is unpredictable Vasodilators are used for prophylaxis or treat- and cumulative effects can result in sudden ment of vascular spasm, and during intraarter- overdosage. ial pressure measurements, to augment distal flow and give a better assessment of the Antibiotics significance of a pressure drop across a lesion. Commonly used intraarterial agents are glyc- When and which antibiotics are used varies eryl trinitrate (GTN, 100mg) (nitroglycerin in according to local policy. Common indications the U.S., 50 to 100mg) and papaverine (30mg). are when prosthetic graft material is likely to be Of course, vasodilators may produce significant punctured during a procedure, when prosthetic hypotension, so attention should be paid to material is to be placed (especially aortic stent- patient hydration status and coexisting cardiac grafts), or for some embolization procedures. disease. Vasodilators should not be used in patients with significant aortic stenosis, as Antiplatelet Agents they may produce severe hypotension in this circumstance. Nifedipine (10mg) can be given All patients with peripheral vascular disease orally prior to a procedure if significant spasm should be advised to take antiplatelet agents, is likely, such as embolization of the testicular predominantly for their cardioprotective effect. vein. Dosages of aspirin likely need be no higher than 75mg daily,although the precise optimal dosage Atropine/Glycopyrronium Bromide has not been definitively determined. If the patient is intolerant of aspirin then dipyri- These agents are given routinely during carotid damole (25 to 50mg) or clopidogrel (75mg) are stenting to reduce the risk of bradycardia and alternative agents. In our practice, patients are hypotension during balloon inflation in the given clopidogrel 75mg at least 3 days prior to carotid bulb. Glycopyrronium bromide (600mg) and for 30 days following carotid stent inser- is preferred in patients with a history of cardiac tion. If the patient has not taken a dose prior disease because it has a better side effect profile to the day of the procedure, a loading dose of (U.S. equivalent is glycopyrrolate, adult dosage 300mg is given on the day of procedure. In the 100mg IV repeated every 2 to 3 minutes as nec- U.S., most centers use both aspirin and clopido- essary with a reasonable upper limit of 600mg). grel for carotid stents. 242

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Drugs for Treating and the patient can be fully mobilized immedi- ately. It can be used for closure of up to a 10F Contrast Reactions sheath size. Another suture-based device, It is imperative to be aware of the risk of a severe Prostar XL (Perclose), has been used success- contrast reaction and its treatment. The drugs fully for closure of 24F femoral artery access. to do this should be readily available on the One of the authors has personally used these resuscitation trolley in the angiography suite. devices with good success for totally percuta- All centers should have a protocol for treatment neous endovascular aortic aneurysm repair, of severe contrast reactions. This should be both abdominal and thoracic. The primary prominently displayed and usually involves issues are vessel size and calcification,which can the use of some or all of the following: chlor- affect the ability of the device to capture the pheniramine (10 to 20mg IV); adrenaline or sutures properly. Obesity and prior surgery or epinephrine (0.5mL of 1:1000 solution subcu- dense scar can also affect these devices. The taneous or 0.1mL of 1:10,000 solution IV), vessel can be immediately reaccessed if neces- usually given if there is severe anaphylactic sary and other than the suture, there is no other shock; hydrocortisone (200mg IV), though its residual material to cause problems if surgery is effects are not immediate; cimetidine (300mg required at the access site. There are a number IV), may be useful as a second-line drug follow- of plugging devices, such as the Angioseal (St. ing adrenaline; atropine (500mg to 1mg IV) can Jude Medical, St. Paul, MN), the Duett (Vascular be used for severe bradyarrhythmia. Solutions Inc., Minneapolis, MN), and the Vasoseal (Datascope Corp., Montvale, NJ). The authors are also quite familiar with the angioseal. This is quick and simple to use and Devices for Vascular comes as a 6F or 8F device. An absorbable shoe Intervention remains inside the artery and a collagen plug is deployed over the puncture site outside the artery. The device now uses a knot mechanism Various devices may be required to perform to hold the collagen plug in position, and the vascular interventional procedures, such as patient can mobilize in 2 to 4 hours. The balloon catheters and stents for treating arterial primary issues with this device are vessel size occlusive disease, or coils for embolization. The and the size of the arterial access device used for specifics of these devices are described during the procedure. discussion on their use elsewhere in this chapter. Access Technique

Closure Devices Before any diagnostic or interventional proce- dure can begin, vascular access has to be estab- Arterial puncture site closure devices aim to lished. The basic technique remains the same as eliminate or reduce the need for manual com- that described by Seldinger: pression of the puncture site, reduce the time to patient mobilization, and reduce the risk • Vessel puncture of significant bleeding, especially when using • Guidewire introduction larger sheath sizes. For most centers it is the • Placement of the catheter over the increased throughput of patients and the ability guidewire to perform intervention as a day case that justifies their use. Vessel Puncture There are a number of devices available, divided into two main groups: “stitchers” and For the purposes of this chapter, only arterial “pluggers.” The Closer (Perclose, CA) device is access is discussed; venous access is discussed the original “stitcher.”It percutaneously places a in Chapter 13. In general, which vessel to punc- suture through the artery at the puncture site, ture is dictated by the site of disease to be inves- 243

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Table 20.2. Arterial access sites Access site Main indications Ipsilateral common femoral artery (CFA) All accessible stenotic/occlusive lesion Contralateral CFA Occluded ipsilateral CFA Lesion to be treated close to ipsilateral groin Scarred groin Low superficial femoral artery (SFA) Percutaneous transluminal angioplasty (PTA) of ipsilateral CFA (rare), SFA origin or proximal graft anastomosis but contralateral femoral puncture not possible Profunda femoris (PF) artery PTA of PF origin PTA of CFA (rare) if SFA occluded and contralateral approach not possible Direct graft puncture Arteriography in patients with graft crossing both groins Intervention at graft anastomoses Occluded graft, to allow accelerated thrombolysis Popliteal artery PTA of occlusions involving the origin of the superficial femoral artery Failure of guidewire passage antegrade, often due to steep, large collaterals at the proximal site of an occlusion Brachial artery Bilateral aortoiliac occlusions PTA of a supraaortic branch occlusion or stenosis Severe aortoiliac disease and vascular tortuosity Axillary artery (brachial approach preferred) As above Radial artery Arteriography as above; limited intervention possible

tigated or treated, and the strength of the arte- gently withdrawn until the tip is felt to flick into rial pulses at various sites. The commonly used the lumen of the artery, and this should be arterial puncture sites are shown in Table 20.2. accompanied by the free pulsatile backflow of For most purposes, the common femoral arterial blood. artery is used, as it is a relatively easy artery to Bony landmarks for the femoral artery on puncture, the artery is readily compressed over fluoroscopy can also be used, namely the medial the femoral head, and most vascular beds are aspect of the femoral head, but direct palpation easily within reach. The vessel is punctured at is preferable. If there are difficulties gaining the point of maximal pulsation, not by means access or if the pulse is weak or absent,then gen- of external anatomical landmarks. At this point erally the best approach is to use ultrasound to the vessel is over the femoral head. The site is directly visualize the arterial target. This is par- first cleaned and draped, and local anesthetic ticularly useful for antegrade femoral artery inserted.A two-part needle is preferred for most punctures, as it often avoids the need to use access as this avoids the risk of damaging the fluoroscopy to guide a wire into the superficial vessel if the tip of the needle has to be reposi- femoral artery (SFA) for distal intervention, and tioned. There is also a reduced risk of the wire hence reduces the risk of irradiating the hands passing into a subintimal position. This can of the operator. In cases of difficult access, a occur because the long bevel of a one-part micropuncture set is commonly used to reduce needle may imply the needle tip is in the center the risk of arterial injury, and in most of these of the lumen of the vessel, when it is only par- sets the guidewire is specifically designed with tially through the wall of the artery. The needle an echogenic tip to aid visualization of the small is guided at about 45 degrees to the skin surface 0.018-inch wire. Once arterial access is obtained toward the pulse, and the vessel is speared. The with a short 4F introducer, an exchange is made central stylet is then removed and the needle for a larger guidewire and 5F sheath. 244

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Guidewire Introduction important role to play. Some techniques, such as laser treatments, have come and gone. Atherec- Once the needle is in position, a guidewire is tomy has a limited role for occlusive disease, introduced through it. For most purposes a predominantly for graft or stent re stenosis, and standard 3-mm J wire is used to secure access stent grafts are being evaluated for occlusive and to allow initial introduction of catheters disease to see if the expense can be justified over and sheaths. The wire should pass smoothly and simple angioplasty or stenting. easily into the artery. If any resistance is felt, fluoroscopy should be used to ensure the wire is following an appropriate course and is running Angioplasty freely. If the wire does not pass beyond a certain The technique of balloon angioplasty is used point, then a limited angiogram may be extensively to treat arterial stenoses and occlu- required to identify the problem, but this sions, and the principles and equipment are requires that at least some wire is within the largely the same regardless of where they are arterial lumen to allow the introduction of a applied. The basic principle is to place a sheath or dilator. If the wire does not pass out guidewire through an arterial narrowing and of the needle, then there is probably an arterial over this to position an appropriately sized plaque at the puncture site. The needle tip can angioplasty balloon. The balloon is then inflated often be repositioned without losing an intraar- to high pressure, disrupting the stenotic arterial terial position, but sometimes re-puncture is plaque. The luminal area, therefore, is increased necessary, perhaps using ultrasound to guide and blood flow improved. the optimal site for puncture. As with all vascular intervention, planning is important and consideration should be given to Catheter Placement the following: Once the wire has been advanced into a suitable Access site: Access should usually be as near position, a catheter or sheath can be introduced to the site to be treated as possible. This over it. The wire is held under slight tension as optimizes tactile control of wires and the catheter is introduced, as this helps to avoid catheters, minimizes a tortuous approach the wire kinking in the soft tissues and makes to a lesion, and may help avoid an awkward tracking the catheter easier. Once the catheter approach to a vessel origin. For distal lower has been advanced into position, the guidewire limb intervention, this usually means an can be removed, the catheter flushed, and the antegrade femoral artery puncture. intraluminal position verified with a test injec- Crossing the lesion: The guidewire has to tion of contrast. lie in an intraluminal position above and If the site of insertion has dense scar from a below the site to be treated (even in cases prior procedure, then insertion of even a small of subintimal angioplasty). For simple sheath or dilator may be difficult. If this is the stenoses, the lesion is crossed intralumi- case, then it is often prudent to use a stiffer nally, often using a directional catheter, guidewire initially or to change to one through such as a Cobra and a curved wire, with or a 4F dilator and then place a sheath for use without a hydrophilic coating. Particularly during the rest of the procedure. Current when treating occlusions, the wire may micropuncture sets also have stiff versions for pass (intentionally or otherwise) into the these cases. Although not needed frequently, subintimal space within the diseased these stiffer versions can be quite helpful. section. The wire usually buckles on itself when this happens, and if a hydrophilic Endovascular Techniques for wire is then used, a loop is formed with it. The wire must then reenter in an intralu- Arterial Occlusive Disease minal position in the more normal distal vessel before balloon dilatation is per- The mainstay of vascular intervention for arte- formed. This often occurs by advancing the rial occlusive disease remains balloon angio- wire loop in the subintimal space, with plasty, though arterial stenting also has an reentry occurring where a collateral arises 245

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or at a vessel bifurcation—the basis of rupture, reinsertion of the balloon and inflation subintimal angioplasty. A Berenstein or under low pressure proximal to the site of other directional catheter can also be used rupture should stop or minimize further bleed- to direct the wire back into the true lumen, ing. This may suffice for a small hole. It is and as with other steps in subintimal prudent to inform a vascular surgeon of the angioplasty, this should be performed with problem. An angiogram should be performed caution to avoid vessel perforation. New after a trial of low-pressure balloon inflation. catheters with If extravasation continues, then the balloon wire guides and over-the-wire “spreading” should be immediately reinflated, and, if avail- devices have recently been produced to able, an appropriately sized stent graft inserted. help cross-total occlusions, but are typi- If this is not possible, then surgical repair of the cally needed only in difficult cases. arterial tear is required. Dilatation of the lesion: Angioplasty balloons If there is no injury and the treated segment fall into two main groups—compliant remains significantly stenosed, then it may be and noncompliant. Noncompliant balloons that the balloon was undersized, in which case inflate to only one size, regardless of pres- increasing the balloon size is often all that is sure, up to their burst rating. Compliant required. In the iliac arteries, a pullback pres- balloons vary in size, dependent on the sure can be performed through the lesion to pressure/volume of fluid within them.Most assess if there is a significant pressure gradient interventionists prefer noncompliant bal- at the site treated. This is usually taken to be loons because they often can be inflated a peak systolic pressure drop of 10mmHg to higher pressure and the risk of over- across the lesion following administration of a sizing of the balloon for the vessel is distal vasodilator, such as GTN or papaverine. smaller. The size of balloon chosen is At other sites, for example, in the SFA, pres- dependent on the size of the adjacent sures are often not useful, as the catheter has to normal vessel, though most operators use cross the treated segment for a pressure read- an approximate guide based on experience ing to be obtained distally, and this may in and scale the size up or down for individ- itself produce a pressure drop if the lumen is ual patients (e.g., petite elderly women small.A normal distal pressure, however, is reas- have small, fragile vessels). Inflation of the suring that the stenosis has been treated ade- balloon can be performed by hand or using quately. If there is still a significant pressure an inflation device. The latter has the drop in the iliac arteries after apparently ade- advantage of a pressure gauge, allowing quate balloon inflation, then secondary stenting more control of the pressure and less like- is warranted. If elastic recoil seems to be occur- lihood of exceeding the maximum balloon ring on balloon deflation, again, stenting should inflation pressure. Inflation is performed be considered, depending on the site of the with a contrast/saline mix and the balloon lesion. should fully inflate with no “waist.” Some Often following angioplasty,a local dissection operators inflate for a short period, others is visualized; however, most of these will for 2 to 3 minutes, and some initially at remodel and do not require further treatment. high pressure,reducing to a prolonged low- If there is evidence of flow limitation, then there pressure inflation. The basis for this is to is a risk the segment will acutely occlude, and reduce the risk of distal embolization and further investigation/treatment is warranted. significant dissection. However, the evi- Again a pressure measurement can be per- dence that these strategies achieve these formed. For further treatment a long low-pres- aims is lacking. sure inflation may tack back the dissection, but if this is unsuccessful, stenting may be Following angioplasty a completion angio- required. gram should be performed to assess the appear- Imaging the runoff vessels ensures that there ance of the treated segment and the “runoff.” has been no distal embolization. If this has Of primary importance is exclusion of vessel occurred and the embolus is in an important rupture with contrast extravasation, particu- vessel or producing poor flow/limb ischemia, larly in the iliac arteries. If there is arterial then thrombo-aspiration should be performed 246

VASCULAR SURGERY using an appropriate-size catheter for the here, with some examples given of those with occluded vessel and a sheath with a removable which the authors are most familiar. hemostatic valve. Types of Stent Stenting Stents fall into two main groups: balloon- Intravascular stenting places a metallic scaffold mounted or self-expanding. Balloon-mounted inside the vessel to hold open the lumen. Stents stents are usually made of stainless steel and were developed as an adjunct to balloon angio- are positioned on an angioplasty balloon for plasty in recognition that angioplasty alone was expansion and deployment. There is usually occasionally unsuccessful. In this circumstance, little shortening with expansion, and balloon- the role of stenting is secondary to the primary mounted stents are particularly useful where treatment of angioplasty and is used to salvage positioning of the stent is critical, enhanced a failed angioplasty. However, there are occa- by their radiopacity. Larger balloon-mounted sions when stenting is the initial treatment, so- stents, for example, unmounted Palmaz stents, called primary stenting. Examples include the shorten considerably when expanded on a treatment of ostial lesions, such as ostial renal large-diameter balloon, making their place- artery stenosis (Fig. 20.1); most iliac occlusions; ment more difficult. As these stents are quite and carotid stenosis. The basis for stenting is to inflexible, they may be difficult to position reduce problems caused by elastic recoil or through tortuous vessels. Their rigidity, how- distal embolization. Stents are generally avoided ever, gives them good radial strength, but if below the inguinal ligament, as there is no evi- deformed once placed,for example,in superficial dence they are superior to balloon angioplasty locations, or near joints, they will remain de- alone in this location. In these lower flow formed and may themselves cause vascular vessels, stents may result in early thrombosis obstruction. Most of these stents now come pre- and thus are reserved for bailout situations after mounted on an angioplasty balloon ready for angioplasty. deployment,for example,Bridge stent (Medtonic There are a huge number of types of stents AVE, Santa Rosa, CA), Genesis, or premounted available for intravascular use, and choice of Palmaz (Cordis, Miami Lakes, FL). Others have stent is usually at the discretion of the practi- to be manually crimped to an appropriate tioner. The common types of stent are described balloon prior to use, for example, SAXX (C.R.

Figure 20.1. Renal artery stenting. Gadolinium-enhanced magnetic resonance imaging (A) showing a tight stenosis in the solitary kidney, confirmed by catheter angiography (B) and successfully stented with a balloon-mounted stent (C).Note the left renal artery is occluded (arrow). 247

ENDOVASCULAR APPROACHES AND TECHNIQUES

Bard, Murry Hill, NJ, USA) and the unmounted self-expanding and balloon-mounted stents can Palmaz (Cordis). The premounted stents are less now be introduced through 5F to 6F sheaths. prone to dislodgment from the balloon.This can The basic principles of stenting are analogous occur as the stent is passed through the sheath to those of angioplasty, in the approach to the and into its position for use, or during balloon lesion and use of guidewires and catheters to inflation if a “dumbbell” is not formed around cross the lesion. If there are difficulties tracking the stent as the balloon is initially inflated, in the stent to the lesion, a stiffer guidewire may be which case the stent may be squeezed off the required than for balloon angioplasty alone.The deploying balloon. The latter problem is caused size and length of stent are selected for the size by movement of the stent from the center of the of vessel and the length of the lesion. For self- balloon or poor initial positioning so that one expanding stents the diameter of the stent is end of the balloon inflates first. Care is therefore usually oversized by 1 to 2mm, compared to the required when using these stents,and if the stent vessel diameter. Use of fluoroscopic road- has moved on the angioplasty balloon prior to mapping techniques help ensure that the stent deployment, it should not be used. is appropriately positioned, both prior to and Self-expanding stents all have an inherent during deployment, but this may require the use ability to expand to a predetermined length of a guiding catheter or catheter positioned and/or diameter. They are compressed onto the from another access site to perform angiogra- delivery catheter and are typically constrained phy. Many self-expanding stents, as they deploy, by a covering sheath. As this sheath is with- move away from the operator. Gentle back trac- drawn, the stent expands and is deployed. Being tion on the delivery system and continuous self-expanding, the stent continues to exert an screening during deployment should be used to expansile force on the vessel wall once deployed, maintain the position of the stent markers. Fol- and will show some flexibility and recovery to lowing deployment of self-expanding stents, their expanded shape if compressed or kinked. balloon dilatation can be used to ensure ade- Stents such as the Wallstent (Boston Scientific, quate expansion and apposition to the vessel Boston, MA) are made of surgical grade stain- wall. In some circumstances, for example, small less steel and rely on their design to be self- external iliac arteries, ballooning to the desired expanding. Newer stents tend to be made from vessel diameter may not be possible because the nitinol, for example, the Memotherm Luminex patient may experience pain, and there is a risk (C.R. Bard), or the SMART stent (Cordis). of arterial rupture. In these circumstances it is Nitinol is a highly elastic nickel-titanium alloy prudent to use a self-expanding stent, and in that displays the property of thermal memory, most cases the stent will expand adequately over returning to its preformed shape when released the next few days with no adverse outcome. As in the body. The “memory” properties of nitinol with angioplasty, check angiography with can be made to be more or less sensitive to tem- runoff views should be performed. perature, which can be an advantage in certain situations. Atherectomy The Wallstent shortens considerably as it expands, with its final length governed by the As with many new interventions, there was diameter achieved in the vessel. This can make initially much enthusiasm for atherectomy. accurate placement difficult. It is very flexible, However, the lack of evidence that the technique but has a relatively low expansile force once in was superior to simple balloon treatment for place. Nitinol stents show considerably less atheromatous disease has meant there is now shortening during expansion, and though limited use for this technique. Pending data nitinol is poorly radiopaque, many stents now from newer devices and techniques, the role of have gold or platinum markers on their proxi- atherectomy is mainly limited to removal of mal and distal struts to aid accurate placement. neointimal hyperplasia from graft anastomoses All stents come in a range of diameters and or from within stents. Such lesions tend to be lengths to suit their use in different-sized vessels elastic and resist balloon angioplasty alone. and different lesion lengths.Placement of a stent Stenting is often counterproductive as it may usually requires a larger sheath to allow entry of exacerbate the hyperplastic process (at least the stent into the vascular system, though many pending data using new drug-eluting stents in 248

VASCULAR SURGERY this role). However, the obstructing material can segment. This may mean performing a prelimi- often be removed percutaneously using atherec- nary ultrasound to identify the upper extent of tomy devices. clot if a distal graft or the SFA is thrombosed, to ensure ipsilateral access is possible. This allows easy access to the thrombus and aids adjunctive Stent Grafting procedures such as angioplasty or thrombo- aspiration if necessary. Use of a single arterial Stent grafts are predominately used in the wall puncture technique is preferred, and once domain of aneurysmal disease. They have been access is achieved the guidewire traversal test advocated as an alternative to angioplasty should be performed. If the wire does not and/or stenting for occlusive disease, often as a pass through the thrombus, the success rate form of endovascular bypass procedure. As yet for thrombolysis is reduced, as the thrombus the technique has not shown superior effec- is likely to be organized. A catheter and/or tiveness compared to angioplasty or conven- infusion-type wire should be placed through tional stenting in the iliac arteries, and studies the thrombus and lytic agents delivered into the on their use for long occlusions elsewhere are thrombus. If the catheter is positioned above the ongoing. thrombosed segment, lytic agents are usually carried away by collaterals and the only lytic Thrombolysis/Thrombectomy effect will be systemic.A number ofinfusion techniques are available; the most commonly Thrombolysis may be considered if there is used is bolus lacing of the thrombus (e.g., 5mg acute critical limb ischemia due to thrombosis. of rtPA or 100,000 to 250,000 units of urokinase) Thrombolytic agents have the potential to break followed by a low-dose (e.g., 0.5mg/h of rtPA, or down the clot, restore perfusion, and reveal the 10,000 units/h urokinase) infusion of lytic agent underlying abnormality that led to thrombosis with the catheter embedded in the proximal in the first instance. The thrombolytic agents extent of the thrombosed segment. There is with which there is most experience for periph- no evidence that a high-dose technique (e.g., eral use for limb ischemia are recombinant 5mg/h of rtPA) or pulse spray techniques tissue-type plasminogen activator (rtPA), strep- improve outcomes. However, it may be neces- tokinase, and urokinase. Urokinase was with- sary to use these techniques if the degree of drawn for some time, but has recently been ischemia does not allow time for a low-dose returned to commercial availability. approach, because although they are labor Thrombolysis is indicated only if there is crit- intensive, they do achieve lysis more quickly. ical limb ischemia, and only then if the limb is The catheter and sheath should be secured salvageable, there is sufficient time for lysis to be using a suture to minimize the risk of displace- instigated, and there are no contraindications to ment. Loss of the sheath at the groin may result giving lytic agents. Its use is usually limited to in hemorrhage, and if the catheter is pulled the following clinical situations: back, the effectiveness of the lytic infusion will be lost. Patients undergoing lysis are in danger • Graft thromboses of a number of complications, predominantly • Native vessel thromboses those of hemorrhage and the effects of reperfu- • Thrombosed popliteal aneurysm with sion injury, and should be monitored in a high- occluded runoff dependency area. Analgesia should be given IV and the amount required reviewed regularly, In general terms the fresher the thrombus, the as reperfusion injury may also cause pain. The more likely the thrombolysis is to be successful. effect of the lytic regime is checked angio- Many clinicians do not consider thrombolysis if graphically after an appropriate period, and if the thrombus is more than 2 weeks old, based necessary the catheter position changed and partly on the STILE trial data that suggested lysis continued. If there has been no effect after that surgery is associated with a better outcome a reasonable period,then lysis is deemed to have for more chronic ischemia (Weaver et al. 1996). failed and alternative surgical strategies may When considering thrombolysis, access be considered. Complications may lead to the should be as close as possible to the thrombosed procedure being abandoned. If the thrombus 249

ENDOVASCULAR APPROACHES AND TECHNIQUES clears, partially or completely, then adjunctive grafts. At the present time, 50% or more of endovascular or surgical treatment may still be infrarenal AAAs fulfill the necessary criteria to necessary. allow stent grafting depending on device avail- There is usually an underlying cause for ability and the criteria applied for iliac access graft or vessel thrombosis, and to maintain and sealing. Common reasons for unsuitability patency these should be treated immediately are an inadequate aortic “neck” below the renal after they are revealed, usually with angio- arteries; poor access, with small-caliber or tor- plasty and/or stenting. If clot clearance is only tuous iliac arteries; and extensive iliac aneurys- partial, it may be appropriate to attempt percu- mal disease. To some extent, problems with iliac taneous thrombectomy. This can be simple access can be dealt with by using iliac or aspiration of clot using a large-caliber catheter iliac–femoral conduits, but this diminishes through a removable hemostatic valve, or using some of the advantages with regard to morbid- specialized mechanical thrombectomy devices ity and recovery time. Extensive iliac aneurys- such as the Amplatz Thrombectomy Device mal disease can also be handled by coiling or (Microvena, White Bear Lake, MN) or the covering the internal iliac arteries, but this Hydrolyser (Cordis). Mechanical thrombectomy is not without some risk of added morbidity devices macerate the thrombus, with the residue compared to standard endovascular repair. either aspirated or small enough to pass through Although undoubtedly a feasible technique with the capillary circulation. Surgical intervention good short-term outcomes, concerns about the may be required even if lysis is apparently suc- long-term results, especially the durability of cessful, for example, fasciotomy for reperfusion the devices, mean that patients require lifelong effects, though more commonly it is needed if surveillance, and in the United Kingdom the lysis is only partially successful, with treatments technique is offered only as part of an ongoing such as graft revision or surgical thrombectomy. study. Lifelong surveillance and participation in organized data collection or a clinical trial are also recommended in the U.S., but commercial Endovascular Techniques for use of stent grafts for endovascular aneurysm repair has been accepted in most parts of the Aneurysmal Disease country following Food and Drug Adminis- tration (FDA) approval of the first devices in The aim of stent grafting is to line the aneurysm 1999. and adjacent normal arterial segments with Although most commonly applied to graft material, therefore excluding the aneurys- infrarenal AAAs, stent grafts can be used for mal segment.There are now many commercially a number of other applications: to exclude an produced devices, manufactured using a variety aneurysmal section of a single vessel such as the of stent and graft materials, usually as a fully iliac artery or the thoracic aorta; to treat vessel supported device with a metal frame covered by rupture, including partial aortic transection fol- graft material. lowing deceleration injury,or iatrogenic rupture Much of the focus in recent years has been on from balloon angioplasty; and to treat the acute the use of stent grafts to treat abdominal aortic ischemic complications of thoracic aortic dis- aneurysms (AAAs). In these circumstances, section. In the case of thoracic aortic dissection, special modular bifurcated devices are the most this is achieved by stent grafting the true lumen frequently used to exclude the aneurysmal covering the entry tear, which usually lies just infrarenal aorta and allow flow into both iliac beyond the origin of the left subclavian artery. arteries. As with any stent graft procedure, it is As a result there is a shift of blood flow from the necessary to have a segment of normal-caliber false to the true lumen and a resolution of many vessel above and below the aneurysm to anchor of the ischemic complications that frequently the device and produce exclusion of the sac occur due to compression of the true lumen by from pressure (and preferably flow as well). a high-pressure false lumen. Although coverage Initially, only about 5% of infrarenal AAAs of the entry tear achieves the acute objectives, could be treated with this technique, but this stable long-term fixation of the device should expanded to 25% to 30% of infrarenal AAAs be in the normal aorta proximal and distal to with the advent of bifurcated and aorto-uniiliac the dissection to prevent erosion of the device 250

VASCULAR SURGERY through the weakened segment of the aortic endoleaks, which are the most dangerous and wall. Treatment of acute dissections requires a should be treated prior to leaving the endovas- thorough understanding of the physiology cular suite if at all possible. Type IV “graft related to flow in the false lumen, and may porosity” endoleaks should seal spontaneously require adjunctive techniques such as balloon in 24 hours, and type II [lumbar artery or infe- fenestration of the dissection distally or stent- rior mesenteric artery (IMA) branch] endoleaks ing of branch vessels. usually seal spontaneously as well, over a period The endovascular techniques used during of weeks to months. Care should be taken not to stent grafting are essentially those of stenting assume that the endoleak is a more benign generally. Devices are sized in terms of length variety, but to confirm the source prior to and diameters to ensure adequate anchorage removing guidewires and catheters. Confir- and to produce a seal proximally and distally mation may require maneuvers such as retro- and to cover the aneurysmal section of vessel, grade injection near the distal end point, according to manufacturer guidelines. Appro- injection within the graft at the location of a priate selection of patient anatomy, device type, modular junction, or other techniques. device diameter, and length are all crucial to the Following endovascular aneurysm repair success of the procedure (Broeders et al., 1997; (EVAR) it is essential that adequate imaging sur- Fillinger, 1999; Wyers et al., 2003). Being large, veillance be performed, as set out in Chapter 4. most stent graft devices have to be introduced This should enable late complications to be through an arterial cutdown at the groin, detected with a view to appropriate treatments, although recently the successful use of arterial as necessary, whether by endovascular or con- closure devices for total percutaneous repair ventional surgical means. have been described. Also, as the devices are often bulky and fairly rigid, very stiff guidewires, such as the Amplatz Superstiff, Lun- Embolotherapy derquist (Cook Inc., Bloomington, IN) or Meier (Boston Scientific, Boston, MA), are used to Embolization techniques involve the deliberate facilitate tracking of the device into position for blocking of blood vessels. This may be neces- deployment (Fillinger, 1999; Wyers et al., 2003). sary to stop arterial hemorrhage, to exclude Accurate deployment is vital to ensure that renal an aneurysm or pseudoaneurysm, to occlude or internal iliac arteries are not inadvertently a branch vessel that may contribute to an covered by the graft material, and this usually “endoleak” as part of endovascular aneurysm requires adjusting the gantry angle for the repair, or to treat vascular tumors and arteri- aortic neck angle. Deployment for most systems ovenous malformations. It is beyond the scope involves the unsheathing of the device, but of this chapter to describe the use of emboliza- deployment mechanisms may include self- tion in detail for all these indications, but expansion (e.g., Medtronic AneuRx or Talent), a some general principles and techniques are release mechanism for a self-expanding device described. (e.g., Gore Excluder), a combination of these In all cases of embolization there are four (e.g., Cook Zenith), or balloon expansion after main considerations: retraction of the sheath (e.g., Edwards Lifepath). Most devices require adjunctive or optional • What is the anatomy? balloon inflation to seat the device within the • What needs embolizing? vessel. In part this is because hooks or some • What embolic material should be used? other attachment device may be present to • Maintain patient safety. help anchor the proximal or distal stents. For modular devices, the different parts are Usually noninvasive testing or the clinical sce- deployed separately, reducing the size of the nario will indicate the likely answers to the individual delivery systems. above considerations. However, an understand- At completion, angiography is performed to ing and knowledge of the vascular anatomy is ensure that there is no evidence of leak into the vital. This can usually be helped by high-quality aneurysm sac. The key for completion angiog- angiography, which should be performed before raphy is to confirm the absence of type I (attach- embolization begins, during embolization as ment site) or type III (stent-graft junction) flow dynamics may change, and at completion. 251

ENDOVASCULAR APPROACHES AND TECHNIQUES

Once the anatomy becomes clear, then the target sizes from 150 to 1000mm in diameter. When for embolization should also become clear. It injecting particles, it is important to ensure that may be a whole vascular bed or a single inflow full stasis is not obtained before all embolic vessel. The type of embolic material is dictated material in the catheter has been injected; oth- by the embolization site and whether perma- erwise further injection will produce significant nent or temporary occlusion is required. During reflux. Flush the embolic material mixed with embolization procedures, a separate trolley contrast from the catheter with saline, and then should be used for the preparation of the it is safe to perform angiography. embolization material. In addition, to avoid Coils are permanent embolic agents that act accidental injection of the material, all contam- as a focus for thrombosis within the vessel. They inated syringes, contrast, and saline should be are metallic, but covered by thrombogenic discarded and replaced. threads. They are best used to occlude a single Before starting, consideration should be vessel or number of discrete feeding vessels to given to the approach to the embolization site. isolate a vessel or area of the circulation. Coils The shortest, straightest route is usually the come in a variety of sizes. The wire diameter best. Preliminary angiography may reveal the varies from 0.014 to 0.038 inch and is important need for equipment, such as guiding catheters to consider, as a large gauge will not pass down or microcatheters. Single end-hole catheters a small-lumen catheter, such as a microcatheter. should always be used, and a guide catheter may Coil length also varies, with shorter coils being be used to help ensure that a stable catheter most easily managed. The formed coil diameter position is achieved. When embolizing, always dictates the size the coil will form in the vessel consider the effects of collaterals, as they may and should be appropriate for the location being carry embolic material away from their target embolized: too small and the coil may migrate; and damage normal tissues, in which case the too large and it may not form well in the vessel. catheter position needs to be closer to the target. Always check the stability of the catheter posi- When embolizing a vessel that is not an end tion prior to deploying the first coil. This is done artery, it is important to “close the back door” to by advancing the pusher wire to the end of the prevent potential back-filling once the entry catheter and ensuring the catheter tip does not vessel is occluded. If this is not done, then a recoil or advance. The appropriate wire is stiff lesion will not have been effectively treated, and enough to push the coil but not so stiff as to as the “front door” has been closed, further dislodge the catheter. A Wholey wire has a access for embolization will be impossible. straight flexible tip with a prominent radio- The main embolic agents to choose from are paque mark on the tip to distinguish it from the the following: coil being pushed. If this wire is too stiff, a Bentson or other more flexible wire might Particles: for example, Gelfoam, polyvinyl be preferable. The coil is introduced into the alcohol (PVA) microspheres catheter by pressing the coil introducer into the Mechanical devices: for example, coils and catheter hub and using the appropriate pusher balloons wire to push the coil into the catheter, then out Liquids: for example, sclerosants, glues the distal end of the catheter, deploying the coil in the appropriate place. When particles are injected they flow into Liquid agents are permanent agents and the distal vessels, occluding the vessels according to most potent. They have the potential to rapidly the age of the particles used. Correct selection produce hemodynamic changes resulting in of the size of the particles is important; small inadvertent embolization and can be difficult to particles may pass through a lesion, causing control in this respect. As such, their use should undesirable embolization, whereas large parti- be limited to those with the most experience. cles may not successfully occlude the vascular Absolute alcohol causes immediate thrombosis bed. Gelfoam is a temporary embolic material, as it enters a vessel. It is the ultimate permanent most commonly used by cutting up a sheet of embolic agent and produces so much pain that Gelfoam into pledgets about 1mm ¥ 1mm,that patients usually require general anesthesia. Its when mixed with contrast can be injected principal use is for vascular malformations. through a conventional catheter. PVA is a per- Glues, such as cyanoacrylate, solidify on contact manent embolic agent that comes in a range of with ionic substances in blood, and are injected 252

VASCULAR SURGERY with lipiodol and dextrose solutions to ensure References they do not solidify in the catheter. Once again, it is an unforgiving material but can be useful Broeders IA, Blankensteijn JD, Olree M, Mali W, Eikelboom and does not produce the severe pain likely with BC. (1997) J Endovasc Surg 4:252–61. other liquid agents. In general, liquid agents are Fillinger MF. (1999) Surg Clin North Am 79:451–75. best mixed with a contrast agent if they are not Weaver FA, Comerota AJ, Youngblood M, Froehlich J, already radiodense, so the amount of injection Hosking JD, Papanicolaou G. (1996) J Vasc Surg 24: 513–21. and extent of delivery can be detected under Wyers MC, Fillinger MF, Schermerhorn ML, et al. (2003) J continuous fluoroscopic guidance. Vasc Surg 38:730–8. Index

A Acrocyanosis, 79 Abdomen, vascular injuries to, 128–130 Activated clotting time (ACT), 41 Abdominal aortic aneurysms, 12, 13, 193–207 Activated partial thromboplastin time (aPTT), 41, clinical features of, 194 43 complications of, 204 Activated protein C resistance (APCR), 48 definition of, 193 Acute mesenteric ischemia (AMI), 231–234 diameter of, 196–197 Adrenaline, 172 endovascular repair of, 202–204, 249–250 b-Adrenergic antagonists, 59 anesthesia for, 67 Advanced Trauma Life Support (ATLS), 129 long-term costs of, 25 Afterload, cardiac, aortic cross-clamping-related epidemiology of, 193 increase in, 68 familial, 192 Agency for Healthcare Research and Quality inflammatory, 206–207 (AHRQ), 149 non-ruptured (elective), management of, 196–204 Alternative medical therapy, for lower limb anesthesia for, 66 ischemia, 95 aneurysmal expansion rate in, 197 Amaurosis fugax, 161, 163 aneurysmal size in, 196–197 Ambulatory venous pressure (AVP), 107 complications of, 200–202 American Board of Surgery, 153 endovascular repair technique, 202–204 Amputations open repair technique, 199–202 Buerger’s disease-related, 87 patient comorbidity in, 197 combat injuries-related, 125 preoperative assessment in, 198–199 concomitant vascular and nerve injuries-related, proximal extent of aneurysm in, 197 130 surgeon’s audited results in, 198 in diabetic patients, 58 pathogenesis of, 192 lower limb ischemia-related, 95, 97–98, 100 radiological investigations of, 29, 35–36 peripheral vascular disease-related, 53 risk factors for, 193–194 Analgesia, 241 ruptured “Anatomical snuff box” gender differences in, 193 as arteriovenous fistula access site, 142 leaking, 205 pulse in, 13 as mortality cause, 193, 204–206 Anesthesia, for vascular surgery, 65–72, 241 operative repair of, 198, 204–206 for carotid endarterectomy, 69–70, 172, 176 in peripheral arterial disease patients, 53 for endovascular interventions, 66–67 symptoms of, 205 general, 65–66, 67–69, 69, 172, 176 screening for, 196 local anesthesia, 240 Accreditation Council for Graduate Medical in carotid endarterectomy, 172 Education (ACGME), 153 for lower extremity vascular surgery, 70–71

253 254

INDEX

Anesthesia, for vascular surgery (cont.) of the subclavian artery, 186–187 for upper extremity vascular surgery, 71–72 for endoleak detection, 36, 250 locoregional, for carotid endarterectomy, 172 magnetic resonance, 30 regional, 65–66, 69–70, 71–72 of carotid disease, 165, 166 contraindications to, 71 of the mesenteric arteries, 35 risks associated with, 65–66 of the proximal common carotid artery, 187 tumescent, 67 of pulmonary embolism, 33 Aneurysms, 191-219. See also Pseudoaneurysms of the renal arteries, 35 aortic. See Aortic aneurysms of the subclavian artery, 186–187 axillary arterial, 218 post-angioplasty, 245 axillosubclavian arterial, 218–219 of renal artery stenosis, 35, 223–224 “berry,”88 of subclavian arterial aneurysms, 217 carotid arterial, 218–219 of thoracoabdominal aortic aneurysms, 209 false, 158 Angioplasty true, 158, 159 percutaneous transluminal classification of, 191–192 as fibromuscular dysplasia treatment, 88 definition of, 191 mesenteric, 234–235 false, 158, 202 as renal artery stenosis treatment, 226 femoral arterial, 213–214 as supra-aortic trunk disease treatment, iliac arterial, 214 184–185 mesenteric arterial, 34, 35, 216 as renal artery stenosis treatment, 225–226 pathogenesis of, 192 of the subclavian artery, 187 popliteal arterial, 13, 210–213 techniques in, 244–246 duplex imaging evaluation of, 22–23 Angioplasty balloons, 245 as limb ischemia cause, 101, 104 Angiotensin-converting enzyme inhibitors, 88, management of, 211–213 222 popliteal pulse in, 93 Angiotensin II, captopril blockage of, 225 ruptured, 211–212 Angiotensin II receptor antagonists, 78 rupture of, 192, 211–212 Ankle block, 71 subclavian arterial, 185, 186, 218 Ankle-brachial index (ABI), 19, 150–151 traumatic, 13 in chronic venous insufficiency, 109 visceral arterial, 214–217 definition of, 15 Angiitis, cutaneous leukocytoclastic, 85 in diabetes mellitus, 19 Angina, mesenteric, 34–35 effect of exercise testing on, 20 Angiogenic therapy, for limb ischemia, 98 in lower limb ischemia, 93, 94, 95 Angiography in peripheral arterial disease, 53, 58 of abdominal aortic aneurysms, 195–196 Antibiotics, indications for use of, 241 in blunt abdominal trauma patients, 129 Anticoagulation therapy, 66, 99–100, 127 carotid, 156, 159, 165, 178–179, 188 Antihypertensive therapy, guidelines for, 59 of the carotid arch, 25 Antineutrophil cytoplasmic antibodies (ANCAs), 79, catheter, 26–28 80, 83 of abdominal aortic aneurysms, 35–36 Antioxidant therapy, 8 complications of, 29 Antiphospholipid antibody syndrome, 50 of endoleaks, 36 Antiplatelet therapy, 1, 54–56, 166–167, 172 of peripheral vascular disease, 31 Antiplatelet Trialists Collaboration, 56, 166, 167 pulmonary, 33 Antithrombin III deficiency, 48 complications related to, 140 Aorta computed tomography abdominal of peripheral vascular disease, 31 aneurysms of. See Abdominal aortic aneurysms of the proximal common carotid artery, 187 diameter of, 193 pulmonary, 25 palpation of, 14 contrast thoracic, trauma-related disruption of, 128 of carotid disease, 165 traumatic injuries to, 37, 128 of lower limb ischemia, 95 Aortic aneurysms of cystic adventitial disease, 89 abdominal. See Abdominal aortic aneurysms digital subtraction, 26 thoracoabdominal, 207–210 of carotid artery disease, 156, 159 Aortic dissection, 36–37, 100 of the proximal common carotid artery, 187 Aortic reconstruction, complications of, 137 255

INDEX

Aortic surgery, open rupture of, 7, 157–158 anesthesia for, 67–69 stable versus unstable, 7 pharmacological considerations for, 68–69 Atrial fibrillation, 156, 167–168 Aortitis, 81, 208 Atriofemoral bypass grafting, 68 Aortobifemoral bypass, long-term results of, 96 Atrophie blanche, 105, 108 Aortofemoral bypass, 68, 101–102, 102 Atropine, 241 Apolipoproteins, 4–5 Auscultation, 14 L-Arginine, as lower limb ischemia treatment, 95 Axillary artery Arterial bypass. See also specific types of arterial cystic adventitial disease of, 89 bypass traumatic injuries to, 130 as limb ischemia treatment, 101–102 as vascular access site, 243 Arterial pressure index (API), Doppler, 126 complications of, 140 Arterial reconstruction, complications of, 134–135 Axillary artery/vein dissection, anesthesia for, 71 Arteriography. See also Angiography Axillobifemoral bypass, in abdominal trauma of abdominal aortic aneurysms, 195–196 patients, 130 arch, of innominate artery occlusive disease, 183 Axillofemoral bypass, 66, 68, 71, 102 of axillary artery aneurysms, 218 Axillosubclavian artery aneurysm, 217 of popliteal arterial aneurysms, 211 Azathioprine, as giant cell arteritis treatment, 160 Arteriovenous access grafts autogenous. See fistulas, arteriovenous B nonautogenous, 141, 143 Bandaging, multilayer lymphedema (MLLB), 120, complications of, 145–146 121 Arteriovenous malformations, pulmonary, 33–34 Banding, of arteriovenous fistulas, 145 Arteritis Benzodiazepines, 241 giant cell, 80, 160, 163, 181 Benzpyrenes, as lymphedema treatment, 122 radiation, 160, 185 Beta blockers, use in peripheral arterial disease Takayasu’s, 32, 80–81, 157, 159, 163, 181, 185 patients, 59 Artery of Adamkiewicz, ligation of, as paraplegia Bleeding disorders, 39-42. See also Coagulation cause, 202 disorders Aspirin, as hemorrhage risk factor, 39, 40 Blood flow Aspirin therapy, 54–55, 76, 166, 167, 241 mesenteric, 231 Asymptomatic Carotid Atherosclerosis Study normal venous, 106–107 (ACAS), 169, 170–171, 173, 179 Blue digit syndrome, 31 Asymptomatic Carotid Surgery Trial (ACST), 169, Blunt trauma, 125 170–171, 173 abdominal, 128–129 Atherectomy, 247–248 to the carotid artery, 127 Atheroma, 5–6 to the extremities, 130, 131 Atherosclerosis, 1–8 to the neck, 127, 160 of the carotid artery, 156–157 Bovine branch anomaly, 182 clinical history of, 10 Brachial artery epidemiology of, 1–2 distal, cystic adventitial disease of, 89 of the innominate artery, 181 as vascular access site, 243 lipid metabolism in, 3–5 Brachial plexus, traumatic injuries to, 126, 130 lipid profiles in, 59 clinical assessment of, 128 as lower limb ischemia cause, 91, 92, 93 Brachial plexus blocks, 71–72 pathogenesis of, 5–7 Breast cancer, mortality rate in, 54 prevention of, 7–8 Breast cancer treatment, as lymphedema-related radiation-induced, 181 pain cause, 120 regression of, 6–7 British Hypertension Society, 59 risk factors for, 2–5 Bruits of the subclavian artery, 185 carotid, 14, 93, 164–165, 183 as systemic vascular disorder, 53 subclavian, 183 theories of, 5–7 vascular injury-related, 126 as thoracoabdominal aortic aneurysm cause, 208 Buerger, Leo, 86 Atherosclerotic plaques, 5–7 Buerger’s disease, 31, 86–87, 91 carotid, 157–158 Buerger’s test, 14 fibrous, 5 Bullets, velocity of, 126 fibrous cap of, 5, 157 Bupivacaine, 66, 240 256

INDEX

C CAVATAS study, 180 Calcitonin gene-related peptide, 74, 78–79 Cavography, 109 Calcium channel blockers, as Raynaud’s Celiac artery phenomenon treatment, 76, 77–78 aneurysms of, 216 Calf muscle, venous blood pumping function of, duplex ultrasound examination of, 234 106–107 Cerebral perfusion pressure (CPP), 69 Capillaroscopy, 76 Cervical plexus block, 69, 70 Capillary refill test, 13 Cervical rib, 76, 185, 187, 217 CAPRIE (Clopidogrel versus Aspirin in Patients at Charles operation, for lymphedema, 122 Risk of Ischemic Events) study, 56, 167 Chest, vascular injuries to, 128 Captopril, 225 Chewing tobacco, as Buerger’s disease cause, 86 Carbon dioxide, as vascular contrast media, 27–28 Cholesterol, hepatic production of, 3 Cardiac failure, high-output, 145 Churg, Jakob, 84 Cardiovascular disease, as mortality cause, 1 Churg-Strauss syndrome, 84–85 Carotid arteries Chylomicrons, 3, 4 aneurysms of, 218–219 Cilostazol (Pletal), 61–62, 95 false, 158 Claudication true, 158, 159 as amputation cause, 95 dissection of, 127, 129, 158–159, 163 chronic limb ischemia-related, 10 external, in carotid endarterectomy, 171 cystic adventitial disease-related, 88 internal exercise testing evaluation of, 20 in carotid endarterectomy, 171, 172–173 innominate artery occlusive disease-related, 181 elongation and kinking of, 158 intermittent, 60 fibromuscular dysplasia of, 158 drug therapy for, 61–62 occlusive disease of, vertebral artery occlusive dyslipidemia-related, 58 disease-associated, 189 effect of smoking cessation on, 2 thrombosis of, as stroke cause, 156 exercise programs for, 60 proximal common, occlusive disease of, 187–188 lower limb ischemia-related, 53, 91, 92–93, 95, stenosis of, 22, 182 98 tortuous, 33, 158 medical management of, 54 traumatic injuries to, 127, 160 natural history of, 53 Carotid artery disease, 155–180 risk factors for, 55, 58 clinical presentation of, 161–163 of the jaw, 163 epidemiology of, 155 neurogenic, differentiated from vascular investigation of, 164–166 claudication, 92–93 management of, 166–175 thoracic outlet syndrome-related, 186 medical, 166–168 upper-limb, 11 surgical, 169–175 venous, 108 pathology of, 157–160 Clinical status, 150–151 postoperative management of, 175–179 Clopidogrel, 56, 166, 167, 241 prognosis of, 164 Clopidogrel versus Aspirin in Patients at Risk of radiological investigations of, 32, 33 Ischemic Events (CAPRIE) study, 56 Carotid body tumors (CBTs), 32, 160 Closure devices, arterial, 25, 26, 242 Carotid bypass, 175 Clotting disorders. See Coagulation disorders Carotid-subclavian bypass, 187 Coagulation cascade, 42 Carotid surgery, anesthesia in, 69–70 Coagulation disorders Catheterization acquired, 46–47 central venous, 141, 142 complications related to, 139–140 epidural, 66 inherited, 42–46 equipment for, 237–240 Cogan’s syndrome, 81–82 as vascular injury cause, 126 Coils, embolic, 251 Catheters, 238–240 Colic artery, aneurysms of, 217 central venous, 141, 142, 143–144, 146–147 Colonic ischemia, postoperative, 202, 206 complications related to, 140, 146–147 Colonoscopy, 202 for embolotherapy, 251 Colorectal cancer, mortality rate in, 54 flushing of, 101, 147, 239, 240–241 Common femoral artery, orthopedic surgery-related placement of, 244 injuries to, 126 types of, 239–240 Compartment pressures, measurement of, 103 257

INDEX

Compartment syndrome, 102–103, 103, 130 D Compression injuries, abdominal, 128–129 Debridement, 22, 130 Compression therapy, 110–111, 121 Deceleration injuries, 126, 128–129 Computed tomography (CT), 28-30. See also Decongestive lymphedema therapy (DLT), 120 Angiography, computed tomography Deep venous reconstruction, as varicose veins of abdominal aortic aneurysms, 36, 195, 199, treatment, 112–113 205 Deep venous thrombosis of arteriovenous fistulas, 123 abdominal aortic aneurysm repair-related, 202 of carotid disease, 165–166 chronic venous insufficiency-related, 107 of inflammatory abdominal aortic aneurysms, hypercoagulability-related, 61 207 as lymphedema cause, 118 of innominate artery occlusive disease, 183 medical management of, 54 of lower limb ischemia, 93, 95 Dense granule deficiency, 46 of lymphedema, 119 Dermatitis, chronic venous insufficiency-related, of popliteal arterial aneurysms, 211 105, 108, 110 of subclavian arterial aneurysms, 217 Diabetes mellitus of thoracic trauma, 128 ankle-brachial index (ABI) in, 19 of thoracoabdominal aortic aneurysms, 208 as atherosclerosis risk factor, 1, 2 Congestive heart failure, incidence of, 2 hypertension management in, 59, 167 Connective tissue disorders, Raynaud’s lower limb ischemia associated with, 91, 97 phenomenon-related, 75, 76 negative correlation with abdominal aortic Continuous quality improvement (CQI), 152–153 aneurysms, 193–194 Contrast agents, 26, 27–28 peripheral arterial disease associated with, 55, 58, first use of, 25–26 59 nephrotoxicity of, 27, 33, 95, 224 Dialysis Outcomes and Practice Patterns Study reactions to, 242 (DOPPS), 142 Cooperative Study of Renovascular Hypertension, Dialysis patients, vascular access in, 141–148 221–222 Diazepam, 66–67 Corona phlebectatica (ankle/malleolar flare), 105, Digital pressures, measurement of, 20 108 Diphenhydramine, 66–67 Coronary artery disease (CAD) Dipyridamole, 56, 166, 241 carotid disease-related, 65 Distal revascularization-interval ligation (DRIL), cholesterol as risk factor for, 6 145 incidence of, 2 Dorsalis pedis artery, absence of, 19 as mortality cause, 1 Dressings, for chronic venous insufficiency peripheral arterial disease-related, 53 management, 109–110 postoperative, 133 Drug injection, intraarterial, adverse effects of, prevention of, with cholesterol-lowering therapy, 16–17, 131 7, 8 Drugs. See also names of specific drugs supra-aortic trunk disease-associated, 183 as bleeding risk factor, 39, 40 Coronary-subclavian steal syndrome, 186 Dysarthria, 163 Corticosteroids, as giant cell arteritis treatment, 80, Dysfibrinogenemias, 49 160 Dyshypoplasminogenemias, 49 Cost outcomes, in vascular surgery, 152–153 Dyslipidemia, management of, 58–59 Cranial nerve palsy, 159, 218–219 Dysphagia, 163 C-reactive protein, in giant cell arteritis, 80 Dysplasia, fibromuscular, 87–88 Critical closing pressure (CCP), in lower limb of the internal carotid artery, 158 ischemia, 93 radiological investigations of, 35 Cross-clamping, aortic, effect on cardiac afterload, as renal artery stenosis cause, 222, 225 68 as stroke cause, 157 Crush injuries, 126, 128 subtypes of, 158 Cryoglobulinemia, essential mixed, 85 Cryoglobulins, 85–86 E Cyanoacrylate, 252 Eczema, 105, 108, 120 Cyanosis, Raynaud’s phenomenon-related, 75 Edema Cyclophosphamide, 84, 160 chronic venous insufficiency-related, 108–109 Cystic adventitial disease, 88–89 pulmonary, “flash,” 224 Cytokines, 6, 157 Ehlers-Danos syndrome, 158–159 258

INDEX

Elastases, 7 for supra-aortic trunk disease, 184–185 Elastic bandages, 110–111, 121 for Takayasu’s arteritis, 81 Elderly patients, brachial emboli in, 12 for thoracoabdominal aortic aneurysms, 210 Electrocardiography, preoperative, 198 vascular intervention devices for, 242 Elephantiasis, as lymphedema cause, 118 Epidural anesthesia, 66, 71 Embolectomy. See also Embolotherapy Errors, medical, 149 as lower limb ischemia treatment, 100–101, 103 Erythrocytes, in Raynaud’s phenomenon, 75 Embolic agents, 251–252 Erythrocyte sedimentation rate, 80, 83, 198 Embolism Erythromelalgia, 79 cardiac, as ischemic stroke cause, 156 Estrogen, 39, 75 cholesterol, 161, 162 European Carotid Surgery Trial (ECST), 169–170 common sources of, 11 EuroQol, 152 distal, of the supra-aortic trunk, 189 Exercise endovascular abdominal aortic aneurysm repair- health benefits of, 60 related, 204 lymphedema-exacerbating effects of, 122 as lower limb ischemia cause, 98–99, 100–101, Exercise testing, 20 103, 104 in lower limb ischemia patients, 94–95 mesenteric, 232, 233 Exercise therapy pulmonary, 32–33, 202 for lower limb ischemia patients, 95 as upper limb ischemia cause, 16, 17 for peripheral arterial disease patients, 60 as upper limb vascular disease cause, 11 Embolotherapy, 250–252 F Endarterectomy Factor deficiencies, 42–45 carotid, 169–179 Factor inhibitors, 46–47 anesthesia for, 66, 69–70 Fasciotomy, 102–103, 130 atherocsclerotic plaque excision in, 157 Fatty streaks, 5 bifurcation, of the proximal common carotid Femoral arteries artery, 188 aneurysms of, 13, 213–214 cerebral protection in, 69 superficial comparison with carotid angioplasty, 179–180 aneurysms of, 13 effect on stroke risk, 169–171 distal, occlusive disease of, 96 monitoring during, 66 as hemodialysis access conduit, 147 neurological deficits associated with, traumatic injuries to, 130–131 176–178 as vascular access site, 243 operative principles of, 171–175 Femoral artery punctures, complications of, 131, 140 postoperative management of, 175–179 Femoral-femoral bypass, 96, 101–102 preoperative hypertension control for, 167 Femoral-popliteal bypass, 96 traditional versus eversion, 174 Femoral shaft fractures, 126 in vertebral artery stenosis/occlusion, 189 Femoral-tibial bypass grafting, 97 transaortic renal, 226 Fentanyl, 67 transthoracic innominate, 183, 184 fibrinogen, 41 Endoleaks, 36, 204, 250 fibrinogen abnormalities, 45 Endothelin-1, in Raynaud’s phenomenon, 74–75 filiariasis, as lymphedema cause, 118 Endovascular approaches and techniques, 237-252. fistulas See also Embolotherapy; Stenting; Stent aortocaval, 194 grafting aortoduodenal, 194 for abdominal aortic aneurysms, 67, 202–204 arteriovenous, 123, 124, 128, 131, 141, 142–143 conversion to open repair, 204 complications of, 144–145 access techniques, 242–244 carotid-cavernous sinus, 128 anesthesia in, 66–67 flavonoids, as lymphedema treatment, 122 for aneurysmal disease, 249–250 fluid management, perioperative, in patients with for arterial occlusive disease, 244–249 ruptured aortic aneurysms, 201 for arterial trauma, 131 Framingham Study, 6 for carotid aneurysms, 218, 219 Functional status, 151–152 equipment for, 237–240 medications used in, 240–242 G radiological investigations with, 25–26 Gadolinium chelate, 28 for renal artery stenosis, 226–227 Gangrene, 17, 91, 92, 93, 94, 96–97, 131 259

INDEX

Gastroduodenal artery, aneurysms of, 216–217 intraoperative administration of, 173, 240–241 Gingko, 40, 95 as thrombocytopenia cause, 50–51 Glomerulonephritis, Wegener’s granulomatosis- Hepatic artery, aneurysms of, 215–216 related, 84 Hepatitis C virus, 85, 86 Glucocorticoids, as Takayasu’s arteritis treatment, Herbal remedies, as hemorrhage risk factor, 39, 40, 81 41 Glucose tolerance test, 58 Hexopal (inositol nicotinate), 61–62 Glues, embolic, 252 High-density lipoprotein, 2, 4, 168 Glyceryl trinitrate, 241 Hollenhorst plaques, 161 Glycopyrronium bromide, 241 Homan operation, for lymphedema, 122 Grafts, peripheral vascular. See also Stent grafting Homocysteine, 3, 48–59 complications related to, 134–139 Homocystinemia, 61 infrainguinal, duplex imaging of, 22 Horner syndrome, 163 lower limb, occlusion of, 100, 136–137 partial, 159 as lower limb ischemia risk factor, 91 Human immunodeficiency virus (HIV) infection, polytetrafluoroethylene, 96, 97, 102, 135, 118 136 Hunter, William, 125 prosthetic, complications of, 137–139 Hydrothorax, 37 in supra-aortic trunk disease, 183–184 3-Hydroxy-3-methylglutaryl coenzyme (HMG CoA) Granulomatosis, Wegener’s, 83–84 reductase, inhibition of, 3, 5. See also Statin Gray platelet syndrome, 46 therapy Greater saphenous vein, radiofrequency or laser 5-Hydroxytryptamine. See Serotonin ablation of, 67 Hypercholesterolemia, 1, 6, 193 Greater saphenous vein grafts, 135 Hypercoagulable disorders Growth factor therapy, for limb ischemia, 98 acquired, 47, 50–51, 60–61 Guidewires, 237–238, 244–245 inherited, 47, 48–50, 60, 61 introduction through needles, 244 as ischemic stroke cause, 157 Gunshot wounds, 126, 129 peripheral arterial disease-associated, 60–61 supra-aortic trunk disease-associated, 183–184 H as vascular thrombosis cause, 139–140 Hand surgery, anesthesia for, 72 Hyperhomocystinemia, 47, 48–49 Health Plan Employer Data and Information Set Hyperhomocystinuria, 48–49 (HEDIS), 151 Hyperlipidemia, 2, 168 Heart Protection Study, 58, 59 Hyperperfusion syndrome, as stroke cause, 178 Hemangiomas, 123 Hyperplasia, myointimal, 135 Hematomas Hypertension of neck incisions, 176 as abdominal aortic aneurysm risk factor, 193 retroperitoneal, 129 as atherosclerosis risk factor, 1, 3 vascular injury-related, 126, 127, 129 diabetes mellitus-related, 2 Hemianopia, homonymous, 162, 163 management of, 59, 167 Hemophilia, 42–43 drug therapy guidelines for, 59 Hemorrhage fibromuscular dysplasia-related, 88 abdominal, trauma-related, 129 incidence of, 2 chronic venous insufficiency-related, 109 as peripheral arterial disease risk factor, 59–60 femoral artery puncture-related, 131 postoperative, endarterectomy-related, 176 intracranial, carotid endarterectomy-related, renovascular, 221–229 177–178 diagnostic evaluation of, 223–224 perioperative, in abdominal aortic aneurysm pathophysiology of, 222–223 patients, 201 renal artery stenosis-related, 225–226 thrombolytic therapy-related, 248 treatment of, 225–228 vascular injury-related, 126, 127 as stroke risk factor, 3, 167 venous, trauma-related, 130 Hypotension Henoch, Edouard, 85 endarterectomy-related, 176 Heparin vascular injury-related, 126, 128 in catheter saline flushes, 101, 147, 239, 240–241 as contraindication to epidural catheter use, I 66 Ileal artery, aneurysms of, 217 as hypercoagulability treatment, 47, 48 Ileus, laparotomy-related, 201–202 260

INDEX

Iliac arteries Kawasaki’s disease, 82 aneurysms of, 214 Ketanserin, 78 cystic adventitial disease of, 89 Klippel-Trenaunay-Weber syndrome, 117 external, orthopedic surgery-related injuries to, Knee injuries, 126, 131 126 Kocher maneuver, 130 Iloprost, 76, 78 Korean War, vascular surgery during, 125 Imaging. See Radiological investigations Impotence, abdominal aortic aneurysm repair- L related, 202 Lacunar infarcts, 156, 164 Infections Language disorders, carotid disease-related, 163 arteriovenous access graft-related, 146 Laparotomy, as ileus cause, 201–202 arteriovenous fistula-related, 145 Laser ablation, of the greater saphenous vein, 67 central venous catheter-related, 144, 146–147 Leap Frog Group, 149–150 prosthetic graft-related, 137–139 Lecithin-cholesterol acetyltransferase, 4 Inferior mesenteric artery, in abdominal aortic Letessier-Meige syndrome, 117 aneurysm repair, 199–200, 202 Lidocaine, 66, 67, 240 Inferior vena cava Lifestyle risk factors, clinical evaluation of, as hemodialysis access conduit, 147 10 traumatic injuries to, 130 Limb ischemia Inflammation lower. See Lower limb ischemia as aneurysmal disease cause, 192, 206 upper limb as atherosclerosis cause, 6 clinical examination of, 16–17 Infrainguinal bypass, as acute ischemia treatment, radiological investigations of, 32 102 vascular injury-related, 126 Innominate artery Limb pressures, segmental, 19–20, 21 occlusive disease of, 181–185 Limb reduction procedures, as lymphedema traumatic injuries to, 128 treatment, 122 Inositol nicotinate (Hexopal), 61–62 Limbs, vascular injuries to, 130–131 Institute of Medicine, “To Err is Human” report, 149 Limb salvage, in acute lower limb ischemia, Intercostal arteries, in thoracoabdominal aortic 103 aneurysm repair, 209 Lipedema, 119 Intermediate-density lipoprotein, 3, 4–5 Lipid-lowering therapy, 7, 8, 58–59 Internal jugular veins, traumatic injury to, 127 Lipid metabolism, 3–5 Internal mammary artery revascularization, as Lipid profile, “diabetic,” 58 coronary-subclavian steal syndrome cause, Lipodermatosclerosis, 105, 108 186 Lipoprotein (a), 2, 4 International normalized ratio (INR), 41 Lipoprotein lipase, 4 International Society for Cardiovascular Surgery, Liver, cholesterol production in, 3 151 Local anesthesia, 240 Interscalene technique, of deep cervical plexus in carotid endarterectomy, 172 block, 70 in lower extremity vascular surgery, Intravenous immunoglobulin, as Kawasaki’s disease 70–71 treatment, 82 in upper extremity vascular surgery, Ischemia 71–72 colonic, postoperative, 202, 206 Long saphenous vein, 106 limb. See Limb ischemia Long saphenous vein surgery, for varicose veins, mesenteric, 16, 231–234 111–112 popliteal arterial aneurysm-related, 211–212 Lorazepam, 67 Raynaud’s phenomenon-related, 76 Low-density lipoprotein, 1, 2, 3, 4–5, 168 visceral. See Visceral ischemic syndromes small-density, 2, 4 Itching, chronic venous insufficiency-related, 108 Lower limb(s), pallor of, 14 Lower limb ischemia, 91–104 J acute, 98–104 Jejunal artery, aneurysms of, 217 clinical examination of, 16 diagnostic studies of, 99 K five P’s of, 99 Kaposi’s sarcoma, 118 outcomes of, 103–104 Kawasaki, Tomisahu, 82 patient history of, 98–99 261

INDEX

physical examination of, 99 M treatment of, 99–103 Macrophages, 6, 157, 192 chronic, 10, 92–98 Magnetic resonance imaging (MRI). See also abdominal aortic aneurysm-related, 194 Angiography, magnetic resonance clinical examination of, 16 of abdominal aortic aneurysms, 195 diagnostic studies of, 94–95 of carotid disease, 165–166 outcomes of, 98 of popliteal arterial aneurysms, 211 patient history of, 92–93 of thoracoabdominal aortic aneurysms, 208–209 physical examination of, 93–94 Mannitol, 69 treatment of, 95–98 Marfan syndrome, 46, 158–159 critical, 97 Matrix metalloproteineases, 157, 158, 192 acute, 10, 54 Mean arterial pressure (MAP), during carotid amputations in, 97–98 endarterectomy, 69 hypertension treatment in, 59, 60 Medical Outcomes Short Form 36 (SF-36), 151–152 in peripheral vascular disease patients, 53 Mesenteric arteries thrombolytic therapy for, 248 aneurysms of, 34, 35, 216 etiology and presentation of, 91–92 radiological investigations of, 34–35 postoperative, in abdominal aortic aneurysm superior patients, 201 aneurysms of, 216 subclavian artery aneurysm-related, 217 duplex ultrasound examination of, 234 treatment of embolization of, as ischemia cause, 231 amputation, 97–98 thrombosis of, as ischemia cause, 231, 233 medical, 95 traumatic injuries to, 129–130 revascularization, 95–97 thrombosis of, 231, 232, 233–234 Lung cancer, mortality rate in, 54 Mesenteric ischemia, acute, 231–234 Lupus anticoagulant, 50 Mesenteric venous thrombosis, 235–236 Lymph, formation of, 121–122 Midazolam, 241 Lymphadenitis, 118 Middle cerebral artery, 156 Lymphangiography, 119 Milroy’s disease, 117 Lymphangioma circumscriptum, 116 Morphine, 241 Lymphangioma diffusum, 116 Motor deficits, carotid disease-related, 162–163 Lymphangiomas, 116 Multiple Risk Factor Intervention Trial (MRfiT), 2 Lymphangiosarcoma, 116, 119 Mupirocin, 146 Lymphangitis, 118 Muscle death, acute limb ischemia-related, 99, 100 Lymphatic drainage, manual lymphatic (MLD), 120, Myocardial infarction, 7, 53, 201 121 Myxedema, pretibial, 119 Lymphatic system, anatomy and functions of, 113–114 N Lymphedema, 113–122 Naftidrofuryl (Praxilene), 61–62 acute inflammatory episodes (AIEs) associated National Committee for Quality assurance (NCQA), with, 118, 121 151 clinical assessment of, 115–116 National Veterans Administration Surgical Quality definition of, 114 Improvement Program (NSQIP), 149 differential diagnosis of, 115 Neck epidemiology of, 115 anatomic zones of, 127 etiological classification of, 109 innervation of, 69–70 factitious, 119 traumatic injuries to, 126, 127–128, 160 familial, 117 Neck incisions, hematoma of, 176 lymphatic system in, 114 Nephropathy management of, 120–122 contrast agent-induced, 27, 33, 95, 224 pathophysiology of, 114 diabetic, lower limb ischemia associated with, 91 primary, 114, 116–118 ischemic, 221, 223, 228 relationship with chronic venous insufficiency, Nerve injuries, vascular injuries-associated, 126, 118–119 130 secondary, 114, 118–119 Neurological deficits, post-carotid endarterectomy, Lymphedema congenita, 117 176–178 Lymphedema praecox, 117 Neurological examination, of vascular injury Lymphorrhea, 120–121 patients, 126 262

INDEX

Neuropathy as coronary artery disease risk factor, 65 diabetic, 71 diabetes mellitus associated with, 58 ischemic, 104 evaluation instruments for, 152 Neutrophils, in Raynaud’s phenomenon as lower limb ischemia cause, 91 pathophysiology, 75 medical management of, 53–63 Nicotine replacement therapy (NRT), 57 vascular risk factor modification, 53–61 Nifedipine, 76, 241 mortality rate in, 53, 54 Nitroglycerin, 68–69, 78, 241 radiological investigations of, 31 Nitroprusside, 68, 69 Pethidine, 241 Nonsteroidal anti-inflammatory drugs, as Phleboliths, 123 hemorrhage risk factor, 39, 40 Physicians’ Health Study, 56 Noone-Milroy syndrome, 117 Platelet-derived growth factor, 54, 135 North American Symptomatic Carotid Platelet disorders, 45–46 Endarterectomy Trial (NASCET), 166, Platelet factor, 4, 54 169–170, 174 Platelets, in Raynaud’s phenomenon pathophysiology, 75 O Pletal (cilostazol), 61–62 Obesity Plethysmography, 21, 109 adverse health effects of, 57–58 Pneumothorax, 37 management of, 57 tension, 128 in peripheral arterial disease patients, 58 Poiseuille’s law, 95 Ocular disorders, carotid disease-related, 161–162 Polyangiitis, microscopic, 85 Ocular-ischemia syndrome, 161, 162 Polyarteritis nodosa, 82–83, 85 Opiates, 241 Polytetrafluoroethylene grafts, 96, 97, 102, 135, 136 Optic nerve, ischemia of, 161, 162 POPADAD (Prevention of Progression of Arterial Orthopedic injuries, treatment for, 130 Disease in Diabetes), 55, 58 Orthopedic procedures, as vascular injury cause, 126 Popliteal artery Osler-Weber-Rendu disease, 46 aneurysms of, 13, 210–213 Ostial lesions, stenting of, 246 duplex imaging evaluation of, 22–23 Outcome measures, in vascular surgery, 149–154 as limb ischemia cause, 101, 103 Ovarian vein reflux, imaging of, 109 management of, 211–213 Oxfordshire Community Stroke Project, 164 popliteal pulse in, 93 Oxypentifylline (Trental), 61–62 ruptured, 211–212 cystic adventitial disease of, 89 P occlusive disease of, surgical treatment of, 96 Padma Basic, 95 orthopedic surgery-related injuries to, 126 Pallor, 14, 16, 75, 99 traumatic injuries to, 131 Palpation, 13–14, 194, 207, 211 as vascular access site, 243 Pancreatic artery, aneurysms of, 216–217 Popliteal pulse, in popliteal aneurysm, 93 Pancreaticoduodenal artery, aneurysms of, 216–217 Postimplant syndrome, 204 Papaverine, 241 Postthrombotic syndrome (PTS), 107 Paralysis, acute limb ischemia-related, 99 Praxilene (naftidrofuryl), 61–62 Paraplegia, 128, 202 Prazosin, 74 Paresthesia, acute limb ischemia-related, 99 Prednisolone, as Wegener’s granulomatosis Patching, in carotid endarterectomy, 174–175 treatment, 84 Patient satisfaction, 151 Pregnancy, “white leg” of, 107 Penetrating trauma, 125 Prevention of Progression of Arterial Disease in abdominal, 128 Diabetes (POPADAD), 55, 58 to the extremities, 130 Prilocaine hydrochloride, 240 to the neck, 127 Primary valvular incompetence (PVI), 107 thoracic, 128 Pringle’s maneuver, 129 weapon-related, 125 Prostate cancer, mortality rate in, 54 Pentoxifylline, 95 Proteases, 7 Perforator ligation, as venous disease treatment, 112 Protein C deficiency, 49 Peripheral vascular disease Protein S deficiency, 49 asymptomatic, in diabetic patients, 58 Prothrombin time (PT), 41 atherosclerosis risk factor treatment in, 1 Pseudoaneurysms cholesterol-lowering therapy for, 7 of arterial puncture sites, 131, 140 263

INDEX

arteriovenous access graft-related, 146 natural history of, 225 carotid, 127–128 pathophysiology of, 222–223 Pulmonary arteries, imaging of, 32–34 renal-to-aortic ratio (RAR) for, 223 Pulmonary disease surgical management, 223, 224, 225–228, 246 implication for anesthesia, 71 traumatic injuries to, 130 postoperative, 133–134 Renal function, postoperative, in abdominal aortic Pulseless disease. See Arteritis, Takayasu’s aneurysm patients, 201, 206 Pulselessness, acute limb ischemia-related, 99 Renal insufficiency. See also Nephropathy, ischemic Pulselessness, vascular injury-related, 126 contrast agent-related exacerbation of, 95, 224 Pulses in lower limb ischemia patients, 97 abdominal, 14 renal artery stenosis-related, 224 carotid, 13–14 Renal-to-aortic ratio (RAR), 223 lower limb, 13 Renal vein, left, operative exposure of, 227 subclavian, 13 Renal vein renin assays, 224–225 ulnar, 13 Renography, isotope, 225 upper limb, 13 Reperfusion syndrome, as stroke cause, 178 Pulse volume recordings (PVRs), 20–21 Residency training programs, outcomes measures Purpura, Henoch-Schönlein, 85 competency requirement in, 153 Resistive index (RI), in the renal artery, 223 Q Rest pain, 10, 11, 92, 93, 98 Quality-adjusted life years (QALYs), 153 Resuscitation, in abdominal vascular injury Quality analysis (QA), 153 patients, 129 Quality Interagency Coordination Task Force, 149 Retinal artery, occlusion of, 161, 162 Rheumatoid arthritis, as lymphedema cause, R 119 Radial arteries Rib fractures, 128 distal, cystic adventitial disease of, 89 Rubor, 14, 15, 75 traumatic injuries to, 130 as vascular access site, 143, 243 S Radiation, as arteritis cause, 160, 185 Saline, heparinized, 101, 147, 239, 240–241 Radiofrequency ablation, of the greater saphenous Saphenofemoral junction, incompetence of, 14–16, vein, 67 16 Radiological investigations, 25-38. See also specific Saphenopopliteal junction, ligation of, 112 radiological imaging modalities in Saphenous vein, as carotid endarterectomy patch, complications of, 140 174–175 controversies in, 25 SAPPHIRE study, 180 radiation safety during, 30–31 Schönlein, Johann, 85 of trauma, 37 Sclerotherapy, for chronic venous insufficiency, of vascular diseases, 31–37 111 Radionuclide investigations, mesenteric, 34 Scottish Intercollegiate Guidelines Network (SIGN), Raynaud, Maurice, 73 59 Raynaud’s phenomenon, 73–79 Sedation, 241 primary, 73, 75 Seldinger technique, 26 differentiated from secondary, 75–76 Selective serotonin reuptake inhibitors, as secondary, 73, 74, 75–76 Raynaud’s phenomenon treatment, 78 thoracic outlet syndrome-related, 186 Sensory deficits, carotid disease-related, 162–163 treatment for, 76–79 Serotonin, 54, 75 Recombinant tissue-type plasminogen activator, 248 Serotonin antagonists, as Raynaud’s phenomenon Renal arteries treatment, 78 aneurysms of, 216 Short saphenous vein, 106 radiological investigations of, 35 Short saphenous vein surgery, for varicose veins, resistive index (RI) in, 223 112 stenosis of, 221–229 Shunting, in carotid surgery, 69, 173–174 bruits associated with Simvastatin, 8, 59 diagnostic evaluation of, 223–224 Sinus nerve, in carotid endarterectomy, 173 etiology of, 222 Sistrunk operation, for lymphedema, 122 experimental models of, 222–223 Skin perfusion pressure (SPP), 21–22 medical management of, 225–226 “Slipped heart syndrome,” 12 264

INDEX

Smoking with risk factor modification, 167–168 as abdominal aortic aneurysm cause, 193 vertebrobasilar symptoms of, 161, 163, 188–189 as atherosclerosis cause, 1, 2 Subclavian arteries as Buerger’s disease cause, 86, 87 aneurysms of, 185, 186, 217 by occlusive vascular disease cause patients, 12 as arteriovenous fistula access site, 142 as peripheral arterial disease cause, 1, 57 occlusive disease of, 185–187 as stroke cause, 167 cerebrovascular symptoms of, 11 by supra-aortic trunk disease patients, 183 revascularization of, 187 Smoking cessation right, stenosis of, 185 cardiovascular health benefits of, 2 traumatic injuries to, 128, 130 effect on stroke risk, 167 Subclavian steal, 186 in lower limb ischemia patients, 95 Subclavian vein, compression of, 186 methods, 57 Subfascial endoscopic perforator surgery (SEPS), in peripheral arterial disease patients, 1, 57 duplex ultrasound-guided, 112 as weight gain cause, 58 Suction drains, 175 Society for Vascular Surgery, 151 “Sunset foot,” 14 Speech disorders, carotid disease-related, 163 Sympathectomy, as Raynaud’s phenomenon Splenic artery, aneurysms of, 215 treatment, 74, 76–79 Stab wounds, 126 Starling’s forces, 114 T Statin therapy, 7–8, 59 Takayasu, Mikito, 80 Steal, vascular, 145, 146 Thiazides, 59 Stemmer’s sign, 115–116 Thompson operation, for lymphedema, 122 Stent grafting, 248 Thoracic outlet syndrome, 185, 186, 217 of abdominal aortic aneurysms, 202–204, 249–250 Thoracic spine, traumatic injuries to, 128 migration of stent in, 204 Thoracotomy of carotid artery aneurysms, 219 emergent, in thoracic vascular injury patients, devices for, 249, 250 128 postimplantation imaging of, 36 in thoracoabdominal aortic aneurysm repair, 209, types of stents, 246–247 210 Stenting Thrombectomy, 249 intravascular, 246–247 Thrombin inhibitors, 47 of renal artery stenosis, 226–227 Thromboangiitis obliterans. See Buerger’s disease of supra-aortic trunk disease, 184–185 Thromboasthenia, Glanzmann’s, 45, 75 techniques in, 246 Thrombocytopenia, heparin-induced, 50–51 of thoracoabdominal aortic aneurysms, 210 Thromboembolism. See also Deep venous Sticky platelet syndrome, 49 thrombosis Strauss, Lotte, 84 carotid artery aneurysm-related, 218 Streptokinase, 101, 248 as ischemic carotid territory stroke cause, 156 “String of sausages” sign, 233 subclavian artery thromboembolism-related, 185 Stroke venous, hypercoagulability-related, 48 atrial fibrillation-related, 167–168 Thromboendarterectomy, 227, 235 in carotid endarterectomy patients, 176–178 b-Thromboglobulin, 54 in carotid territory. See Carotid artery disease Thrombolytic therapy, 101, 248–249 completed, 161 Thrombophilia definition of, 155 acquired, 60–61 in evolution, 161 inherited, 60, 61, 105–106 hemorrhagic, 156 mesenteric venous thrombosis-related, 235 incidence of, 2 peripheral arterial disease-related, 60–61 investigation of, 164–166 Thrombophilia screen, 41 ischemic, 156–157, 164 Thrombophlebitis, superficial venous, 118 as mortality cause, 164 Thrombosis. See also Deep venous thrombosis perioperative, in supra-aortic trunk disease as acute lower limb ischemia cause, 98–99, 104 patients, 183–184 arteriovenous access graft-related, 146 peripheral arterial disease-related, 53 arteriovenous fistula-related, 145 prevention of central venous catheter-related, 147 with antiplatelet therapy, 166–167 of chronic arterial stenosis, 10 with carotid endarterectomy, 169–179 of collateralized chronic stenosis, 16 265

INDEX

hypercoagulability-related, 139–140 post-carotid endarterectomy, 178 post-endarterectomy, 176–177 of the renal artery, 223

Thromboxane A2, 54, 75 of subclavian arterial aneurysms, 217 Tibial nerve, traumatic injuries to, 131 of the subclavian artery, 186 Ticlopidine, 166–167 of upper limb vascular disease, 32 Tissue factor, 42 of inflammatory abdominal aortic aneurysm, 207 Tobacco use. See also Smoking United Kingdom Prospective Diabetes Study group, as Buerger’s disease cause, 86, 87 167 Toe-brachial index (TBI), in lower limb ischemia, 94 University of Iowa, 67 Topical agents Ureterolysis, 207 for chronic venous insufficiency-related Urokinase, 101, 248 dermatitis, 110 for lymphedema-related eczema, 120 V

Trancutaneous oxygen testing (TcPO2), 97–98 Varices, pelvic, imaging of, 109 Transient ischemic attacks (TIAs), 161 Varicose veins, 12 definition of, 155 arteriovenous fistula-associated, 123 epidemiolgy of, 155 clinical evaluation of, 14–15 innominate artery occlusive disease-related, 182 epidemiology of, 105–106 types of, 161 physical examination of, 108 Trauma radiofrequency or laser ablation treatment of, 67 as acute upper limb vascular disease cause, 11–12 recurrent, surgical treatment of, 112 as axillary artery aneurysm cause, 218 secondary, 107 as carotid artery aneurysm cause, 218 surgical treatment of, 111–113 as innominate artery occlusive disease cause, 181 Vascular access, 141–148 as mortality cause, 125 complications of, 144–147 vascular. See Vascular injuries desperate, 147–148 Trendelenburg test, 14–15 equipment for, 237–240 Trental (oxypentifylline), 61–62 principles of, 141 Triglycerides, 4, 58 standards for, 141–142 techniques in, 242–244 U for thrombolytic therapy, 248 Ulceration types of, 142–144 chronic venous, 109 Vascular disease. See also Peripheral vascular epidemiology of, 105–106 disease management of, 113 clinical evaluation of, 9–18 physical therapy for, 110 clinical examination in, 12–18 foot/lower limb clinical history in, 9–12 differential diagnosis of, 14 patient’s characteristics, 9 ischemia-related, 91, 92, 93–94, 96–97 radiological studies in, 18 skin perfusion pressure evaluation of, 21–22 diabetes mellitus-related, 2 lymphedema-related, 116 lipoproptein (a) as risk factor for, 4 Ulnar arteries nonatherosclerotic, 73–89 distal, cystic adventitial disease of, 89 miscellaneous disorders, 86–89 traumatic injuries to, 130 vasculitis, 79–86 Ultrasonography vasospastic disorders, 73–79 of abdominal aortic aneurysms, 194–195, 198–199 noninvasive examination of, 19–23 Doppler upper limb occlusive, 11–12 of arterial disease, 15–16, 19–20, 21 Vascular examination, noninvasive, 19–23 of arteriovenous fistulas, 123 Vascular injuries, 125–132 fixed waved, 15–16 abdominal, 128–130 waveform analysis in, 21 combat-related, 125 duplex, 22–23, 150–151 diagnosis of, 126 of arteriovenous fistulas, 123 of the extremities, 126, 130–131 of axillary artery aneurysms, 218 iatrogenic, 126, 131 carotid, 32, 164–165 imaging of, 37 of chronic venous insufficiency, 109 mechanism of injury in, 126 of cystic adventitial disease, 89 in the neck, 126, 127–128 of popliteal arterial aneurysms, 211 thoracic, 128 266

INDEX

Vascular surgery. See also specific surgical traumatic injuries to, 128 procedures Vertebrobasilar symptoms, of stroke, 161, 163, complications of, 133–140 188–189 Vasculitis, 79–86 Very-low density lipoprotein (VLDL), 2, 3, 4 cryoglobulinemic, 85–86 Veterans Administration, Surgical Quality large-vessel, 80–82 Improvement Program (NSQIP), 149 medium-vessel, 82–83 Vietnam Vascular Registry, 125 small-vessel, 83–85 Vietnam War, vascular surgery during, 125 Vasoconstriction, Raynaud’s phenomenon-related, Visceral arteries, aneurysms of, 214–217 73 Visceral ischemic syndromes, 231–236 Vasodilation, erythromelalgia-related, 79 acute mesenteric ischemia, 231–234 Vasodilators, 241 chronic visceral ischemia, 234–235 Vasospasm, Raynaud’s phenomenon-related, 73 mesenteric venous thrombosis, 235–236 Vasospastic disorders, 73–79 Visuospatial neglect, 163 Vein grafts, historical background of, 125 von Willebrand disease, 43–44 Velocity analyses, 22 von Willebrand factor, 41 Venoarteriolar reflex, lymphedema-related loss of, 116 W Venous disease Walking Impairment Questionnaire (WIQ), 152 chronic, clinical evaluation of, 17 WALLSTENT study, 180 deep, symptoms of, 12 Wegener, Friedrich, 83 superficial, symptoms of, 12 Wegener’s granulomatosis, 83–84 symptoms of, 12 Weight gain, smoking cessation-related, 58 Venous function, normal, 106–107 Weight-loss programs, 57, 58 Venous insufficiency World Wars I and II, vascular surgery development chronic, 17, 105–113 during, 125 classification of, 105, 106 Wound healing, evaluation of, 21–22 clinical assessment of, 107–109 epidemiology of, 105–106 X nonsurgical management of, 109–111 Xanthelasma, 12 pathophysiology of, 107 X-ray exposure, safety precautions for, 30–31 relationship with lymphedema, 118–119 X-rays surgical management of, 111–113 abdominal, of abdominal aortic aneurysms, symptoms of, 108 194 Venous systems, deep and superficial, 106–107 chest, of traumatic injuries, 37, 128 Vertebral arteries effect of subclavian stenosis on, 11 Y occlusive disease of, 188–190 Yellow-nail syndrome, 117