EDUCATION CLINICAL REVIEW

Management of arteriovenous • Link to this article online for CPD/CME credits Abul Siddiky,1 Kashif Sarwar,2 Niaz Ahmad,3 James Gilbert4

1CRUK/MRC Oxford Institute for The global incidence of patients requiring renal replace‑ SOURCES AND SELECTION CRITERIA Radiation Oncology, University of 1 Oxford, Oxford, UK ment therapy is increasing. In 2012, 108 per million We searched Medline, the Cochrane Database of 2 Leeds City Medical Practice, adults in the United Kingdom started renal replacement Systematic Reviews, and Clinical Evidence online using the Leeds, UK therapy, with a prevalence of 861 per million population.2 3 search terms “arteriovenous ”, “ for Leeds Teaching Hospitals NHS Haemodialysis is one of three viable options for renal Trust, Leeds, UK haemodialysis”, or “renal replacement therapy” for articles replacement therapy alongside renal transplantation and 4Oxford University Hospitals NHS published between 1990 and 2014. Whenever possible we Trust, Oxford, UK peritoneal dialysis. In 2012 in the United Kingdom, 20 332 focused on systematic reviews, meta-analyses, and high Correspondence to: A Siddiky adults were receiving haemodialysis, accounting for 42.7% quality randomised controlled trials. We also consulted [email protected] of all renal replacement therapy and 2.3% more patients the UK Renal Association guidelines (2011) and the US Cite this as: BMJ 2014;349:g6262 than in the preceding year. This is a worldwide problem, National Foundation Kidney Disease Outcomes doi: 10.1136/bmj.g6262 with a little over 370 000 people in the United States and Quality Initiative guidelines (2000). approximately 10 500 people in Australia and New Zea‑ thebmj.com land also receiving haemodialysis.3 4 The purpose of this arteriovenous grafts. Unlike catheters and synthetic grafts, Previous articles in this review is to provide non-specialists with an overview of arteriovenous fistulas are created from native tissue and series arteriovenous fistulas and potential complications. thus avoid the problems from using foreign material, and ЖЖThe diagnosis and they are superior in areas such as complication rates, lon‑ management of hiatus What is an arteriovenous fistula? gevity of the access point, and greater blood flow (box 1).7 hernia An arteriovenous fistula is a direct connection between The cost of maintaining an arteriovenous fistula is only one (BMJ 2014;349:g6154) an and a , created surgically or occurring as a eighth of that for an arteriovenous graft.8 The infection rate ЖЖThe management of result of pathology. Surgically created fistulas were first associated with an arteriovenous fistula is up to 10 times teenage pregnancy described in 1966 following observation of the ease of lower than that of any other form of vascular access and 9 10 (BMJ 2014;349:g5887) phlebotomy and relatively unaffected health of Korean has a considerably better prognosis. Patients with an war veterans with traumatic fistulas in the 1950s.5 6 arteriovenous fistula are less likely to require medical inter‑ ЖЖLaryngitis 11‑13 (BMJ 2014;349:g5827) The principal indication for surgically created arterio‑ vention than those with an arteriovenous graft, with one venous fistulas is to provide access for haemodialysis, a study showing 0.2 interventions versus 1.0 intervention per ЖЖManaging the care process that uses the patient’s blood flow to remove waste patient per year, respectively.13 Arteriovenous fistulas show of adults with Down’s products such as urea, creatinine, and excess water from better survival of long term access than do arteriovenous syndrome the blood. Ordinarily these waste products are dealt with grafts,8 with approximately 90% versus 60%, respectively, (BMJ 2014;349:g5596) by the kidneys but accumulate during kidney failure (figs accessible at one year.14 ЖЖManaging common 1 and 2). In the United States, the Fistula First Breakthrough Ini‑ symptoms of cerebral tiative is a promotional drive for fistulas to become the palsy in children Why are arteriovenous fistulas used for haemodialysis? preferred choice for vascular access for renal replacement (BMJ 2014;349:g5474) Successful haemodialysis requires a reliable access point for therapy.15 Since the creation of the initiative in 2003, the connection to the dialysis machine, with high volume flow, use of arteriovenous fistulas has on average increased by access to superficial (<1 cm from the skin surface) 3.3% annually alongside a concomitant decrease in the for cannulation, and dilation and strengthening of veins to long term use of central venous catheters.16 enable repeated cannulation. Using an arteriovenous fistula UK guidance is equally supportive for preferential use for haemodialysis offers the best short, intermediate, and of arteriovenous fistulas for haemodialysis. Guidelines long term options for renal replacement therapy over other from both the Renal Association17 and the National Insti‑ types of vascular access, such as catheters and synthetic tute for Health and Care Excellence18 propose that 65% of

SUMMARY POINTS The number of patients requiring haemodialysis is increasing worldwide Arteriovenous fistulas provide the ideal means to achieve vascular access for haemodialysis Such fistulas are generally well tolerated Complications include infection, , , aneurysmal change, steal syndrome, and high output cardiac failure An arteriovenous fistula effectively acts as a patient’s lifeline and therefore should be looked after carefully Fig 1 | Brachiocephalic arteriovenous fistula

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Box 2 | Advice for patients with a newly created arteriovenous fistula • Protect against direct trauma to the arm or fistula in the first few days • Avoid overuse of the arm with the arteriovenous fistula • Do not drive or lift heavy objects for the first two weeks • Carry out strengthening exercises, such as squeezing a rubber ball for 2-3 minutes 2-3 times each waking hour in the first few weeks

Box 3 | Advice for patients on the long term care of an arteriovenous fistula • Maintain cleanliness around the puncture site and skin surrounding the fistula • Check for “thrill” and listen for daily • Avoid falling asleep on the affected arm • Avoid tight fitting clothes, jewellery, or watches on the affected arm

Fig 2 | Arteriovenous fistula all incident cases of haemodialysis (65% of all new start‑ being used for haemodialysis Box 4 | Order of preference for vascular access ers each year) and 85% of all prevalent cases (85% of a 1. Arteriovenous fistula: radiocephalic then brachial- unit’s haemodialysis population) should receive dialysis cephalic then brachial-basilic transposition through an arteriovenous fistula. 2. Arteriovenous graft 3. Tunnelled venous catheter How are arteriovenous fistulas looked after and used? 4. Non-tunnelled catheter Patients can take several measures to improve the matu‑ ration and longevity of their arteriovenous fistula (boxes risk of infective complications with buttonhole access.23 2 and 3).19‑21 As soon as an arteriovenous fistula has A cohort study of 90 patients who received haemodialysis been created, overuse, driving, and heavy lifting should at home also found an increase in infective complications be avoided. Patients are also advised to protect the arm (incidence rate ratio 3.85). A systematic review by the from direct trauma. Long term care concerns maintaining same authors further supported this finding.24 Conse‑ cleanliness; carrying out strengthening exercises, such quently, some haemodialysis units have opted to avoid as squeezing a rubber ball; and avoiding exposure of the the buttonhole approach. arm to tight fitting clothes, jewellery, and watches. Blood flow in the fistula can be assessed by palpating What are the alternatives if an arteriovenous fistula is not for a thrill and listening for a bruit. To identify a thrill, possible? the fistula is palpated along its length with at least three When haemodialysis is initiated, the clinical team will fingers or the upper palm of the hand, and a continuous in most cases decide to use an arteriovenous fistula first vibration or buzz can be felt. A bruit can be auscultated and consider other devices for vascular access if that is with a stethoscope at the same time. The strength and not a viable option; all access types should be routinely quality of thrill and bruit differ from patient to patient, discussed with the patient. Initial creation of an arterio‑ and patients are the best judge of whether there has been venous fistula is done as distal as possible in the non- a change. Most changes in thrill and bruit will have been dominant arm and moved progressively proximal, moving identified in the dialysis suite, but it would be recom‑ to the dominant arm if options become exhausted. Box mended that the patient’s general practitioner check for 4 gives an order of preference for vascular access.17 25‑ 27 these on every visit, as examination is quick and easy to However, there are potential but not absolute contrain‑ perform. Healthcare professionals should avoid using the dications to the creation of arteriovenous fistula. These arm with the fistula. If necessary, however, blood can be include pre-existing severe peripheral , Box 1 | Superiority of taken from veins in the back of the hand on the affected cardiac failure, and amputation of the relevant arm. arteriovenous fistulas arm. The main alternative to haemodialysis is peritoneal over alternative Broadly there are three different needling techniques dialysis. In 2012, 6.9% of patients underwent renal haemodialysis access when using the arteriovenous fistula for haemodialysis: replacement therapy by peritoneal dialysis; an increase • Lower risk of infection localised cannulation (area puncture), cannulation using of 0.3% compared with the preceding year.2 Guidelines • Lower risk of thrombosis the length of the fistula (rope ladder), or cannulation are available on the suitability and practicalities of peri‑ • Greater longevity and 17 28 through a formed tract (buttonhole). Buttonhole can‑ toneal dialysis. long term accessibility nulation is currently recommended by the UK Renal Asso‑ • Greater blood flow What are the complications of having an arteriovenous volume ciation following trial outcomes, which showed a lower risk of haematoma and formation than with fistula? • Shorter duration of 17 22 dialysis the rope ladder technique. However, a randomised Several complications are associated with having an arte‑ • Most cost effective controlled trial of 140 patients, which compared standard riovenous fistula. Most of these are identified relatively needling with buttonhole access, identified an increased early through a combination of the patient, dialysis suite, the bmj | 1 November 2014 25 EDUCATION CLINICAL REVIEW

Box 5 | How to assess for and specialist clinic. On occasion, patients may present A PATIENT’S PERSPECTIVE evidence of stenosis with complications to their general practitioner and I’ve been on dialysis for about three years, ever since I Assessment can be if there are any doubts on how to proceed, it would be went to my doctor because I was feeling tired all the time performed in the clinic or perfectly acceptable and perhaps even recommended to and they found that my kidneys were only working at by the patient at home: contact the patient’s dialysis suite or on-call transplant 7%. I had a Tesio line inserted straight away and had my • Have the fistula arm surgeon for advice. fistula made not long after. dependent with the fist In the beginning, I dialysed through the line for the closed Infection first eight weeks whilst waiting for the fistula to set right. • Observe vein filling Infection accounts for 20% of all arteriovenous fistula There weren’t any problems with it really, but it was really • Slowly raise the arm—the difficult to look after it, and bathing and keeping clean related complications.6 29 This varies in severity from arteriovenous fistula was troublesome. When they started to use my fistula, the localised cellulitis (erythema and heat) to abscess for‑ should collapse in the doctors said the dialysis was working even better and I did absence of a stenosis mation (fluctuance and tenderness) and bacteraemia feel a little better too. It’s been much easier to look after • If a section of (pyrexia, rigors, and feeling unwell). Many cases of infec‑ the fistula than the Tesio. You get used to the needling and arteriovenous fistula tion result from needling, with an incidence of periopera‑ they’re trying to form a buttonhole, so that they can use a has not collapsed, the tive infection after the creation of a fistula of around 5%. blunt needle instead. I don’t really mind though because stenosis lies at the Treatment with either oral or intravenous antibiotics is the numbing cream works fine. junction generally successful.30 Localised infection can usually be I’ll be on dialysis now for the rest of my days, so I take treated in the community, but specialist advice should be extra care to ensure the fistula is kept right and proper. sought if there is doubt. It is vital that these patients are FW screened for meticillin resistant Staphyloccocus aureus, vancomycin resistant enterococci, and extended spec‑ trum β lactamase producing organisms using microbio‑ 12.2% (n=53) with treatment compared with 19.5% logical swabs and serum samples, as colonisation can be (n=84) in the placebo arm, the usability of the arterio‑ disastrous to the long term viability of fistulas. Surgical venous fistulas was unchanged. In essence, antiplatelet closure of the arteriovenous fistula may be required if it agents may have some benefit in the early postoperative is the source of recurrent septic emboli.6 9 29 period when thrombosis rates are highest but probably not in the long term. Thrombosis The causes of thrombosis in arteriovenous fistulas are Stenosis and aneurysm manifold and include pre-existing or acquired anatomical Stenosis, thrombosis, and aneurysmal change are often lesions, stenosis, hypercoagulability, and compression of interrelated. Stenosis describes a reduction in the vessel the fistula. Most affected patients will be identified in the lumen by more than 50% and represents the most com‑ dialysis suite but in acute cases—characterised by a sud‑ mon cause of late failure of fistulas.33 Presentation in the den cessation of or reduction in palpable thrill—patients first month after the creation of an arteriovenous fistula should be referred urgently to either vascular or trans‑ is usually due to technical error.34 Neointimal prolifera‑ plant surgical on-call services. tion is caused by multiple factors, such as turbulent blood The UK Renal Association suggests there is little ben‑ flow, endothelial trauma, calcification, and repeated efit from drug treatment in the prevention of thrombus compression, and accounts for most stenoses.34 35 Box 5 and long term accessibility of arteriovenous fistula.17 A describes a simple examination for stenosis. Percutane‑ Cochrane meta-analysis of three randomised controlled ous angioplasty is the treatment of choice, with a success trials from 1974 to 2003 and involving 173 participants rate of greater than 95% shown in a combined retrospec‑ looked at the role of various antiplatelet agents. The tive and prospective review of 1118 salvage procedures in review found some short term benefit but that owing to 364 patients over 12 years in a single centre.36 the age of some studies and the lack of long term follow- Aneurysmal dilatation may occur naturally over time up, these findings should be interpreted with caution.17 31 owing to the increase in blood flow. A noticeable change A more recent study, a randomised, double blind, placebo is often indicative of a downstream stenosis. Surgical controlled trial, assessed the effects of clopidogrel in pre‑ repair may be necessary if there is evidence of overlying venting the early failure of arteriovenous fistula.32 After skin changes and ulceration, which increase the risk of the creation of the fistula, 877 patients were recruited rupture and severe haemorrhage, or if cannulation sites and allocated to clopidogrel (n=441) or placebo (n=436). become limited.37 Although the occurrence of thrombosis was reduced to Ischaemic polyneuropathy TIPS FOR NON-SPECIALISTS Ischaemic polyneuropathy is characterised by paraesthe‑ Regularly check for thrill, bruit, and stenosis (box 5) sia, dysaesthesia, severe pain, and muscle weakness. It Liaise with the patient’s nephrologist and vascular access surgeon if viability is a concern is more commonly seen in patients with pre-existing dia‑ Do not hesitate to discuss minor queries with the nurses in the patient’s dialysis unit as they betes and peripheral vascular disease, especially when will more than likely see the arteriovenous fistula three times a week the brachial artery is used to create the arteriovenous fis‑ Avoid measuring in the arm with a fistula tula.6 38 Treatment is usually aimed at the relief of symp‑ Avoid taking blood from the arm with a fistula; it can be taken from veins on the back of the toms, with a variable response to analgesia. Treatment hand on that side if necessary often requires a multidisciplinary approach, involving Do not cannulate the arteriovenous fistula, except in extremis both primary and secondary care.

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dialysis suite and mild cases can be managed conserva‑ tively. Procedures to reduce blood flow, such as plication, tapering (banding), or distal revascularisation-interval ligation, have been shown to be successful.40

High output cardiac failure An arteriovenous fistula can result in cardiac changes as an adaptation to the increased caused by the shunting of arterial blood from the left to right sided circulation. Consequently, an arteriovenous fistula is thought to increase by 15% and end dia­ stolic ventricular pressure by 4%.6 41 The more proximal the arteriovenous fistula, the greater the risk of high out‑ put cardiac failure developing.42 It is also assumed that the greater the flow through an arteriovenous fistula, the greater the strain on cardiac function. Attempts to find a cut-off for flow have been difficult; however, as high output cardiac failure has been described in patients with flows ranging from 0.6 to 6.5 L/min.43 Patients present with symptoms typical of cardiac failure, such as dys­ pnoea and peripheral oedema, and can be treated accord‑ Fig 3 | Steal syndrome, Steal syndrome ingly. Patients, nephrologists, and cardiologists then have with discoloration of left Steal syndrome is a relatively common side effect of hav‑ the unenviable dilemma between halting the progression hand and healing fingertip ing an arteriovenous fistula, with a reported prevalence of high output cardiac failure and maintaining vascular ulcerations of up to 8% in the population receiving haemodialysis, access for dialysis. and increasing to between 75% and 90% in at risk groups Renal replacement therapy is necessary for the con‑ (elderly patients, patients with diabetes and peripheral tinuation of life and an arteriovenous fistula essentially vascular disease) (fig 3).6 17 39 A well developed arterio‑ acts as the patient’s lifeline. The importance of improv‑ venous fistula can limit (“steal”) the blood flow distal to ing awareness of arteriovenous fistula among the medical the , resulting in relative hypoperfusion of community ultimately will be to the benefit of patients. the extremity and causing considerable pain, a cold hand, Contributors: AS planned, designed, and wrote the article. He is the and discoloration of the skin. The is often weak or guarantor. KS, NA, and JG critically commented on the article. absent and neuropathic features may manifest with time, Competing interests: None declared. culminating in a typical “claw hand” contracture. Symp‑ Provenance and peer review: Commissioned; externally peer reviewed. toms are often identified in a specialist clinic or in the Patient consent: Obtained. 1 Schieppati A, Remuzzi G. Chronic renal diseases as a public health ADDITIONAL EDUCATIONAL RESOURCES problem: epidemiology, social and economic implications. Kidney Int Suppl 2005 Sep;(98):S7-10. Information for healthcare professionals 2 UK Renal Registry. UK Renal Registry: the sixteenth annual report, Dec Renal Association (www.renal.org/home.aspx) 2013. www.renalreg.com/Reports/2013.html. 3 National Kidney and Urologic Diseases Information Clearinghouse. —UK professional body for clinicians interested in renal Kidney Disease Statistics for the United States. 2012. www.kidney. disease niddk.nih.gov/KUDiseases/pubs/kustats/index.aspx#5. UK Renal Registry (www.renalreg.com) 4 Australia and New Zealand Dialysis and Transplant Registry. Haemodialysis. 2012. www.anzdata.org.au/anzdata/AnzdataReport/3 —Useful resource of statistical data for the development of 5thReport/2012c05_haemodialysis_v2.11.pdf. patient care in renal disease 5 Brescia MJ, Cimino JE, Appel K, Hurwich BJ. Chronic haemodialysis using venipuncture and a surgically created arteriovenous fistula. N Engl J American Society of Nephrology (www.asn-online.org) Med 1966;275:1089-92. —US professional body for clinicians interested in renal 6 Stolic R. Most important chronic complications of arteriovenous fistulas disease for . Med Princ Pract 2013;22:220-8. 7 NKF-K/DOQI Clinical practice guidelines for vascular access: guideline Vascular Access Society (www.vascularaccesssociety.com) 29: goals of access placement—maximizing primary AV fistulae. Am J —European professional body for healthcare workers Kidney Dis 2001;37(Suppl 1):S169. interested in vascular access 8 Schon D, Blume WS, Miebauer K, Hollenbeak CS, de Lissovoy G. Increasing the use of arteriovenous fistula in hemodialysis: economic The Vascular Access Society of Britain & Ireland (VASBI) (www. benefits and economic barriers. Clin J Am Soc Nephrol 2007;2:268-76. vasbi.org.uk) 9 Schild AF, Perez E, Gillaspie E, Seaver C, Livingstone J, Thibonnier A. —UK and Ireland professional body for healthcare workers Arteriovenous fistulae vs arteriovenous grafts: a retrospective review of 1700 consecutive vascular access cases. J Vasc Access 2008;9:231-5. interested in vascular access 10 Kessler M, Hoen B, Mayeux D, Hestin D, Fontenaille C. Bacteraemia in Information for patients patients on chronic haemodialysis: a multicenter prospective survey. Nephron 1993;63:93-100. National Kidney and Urologic Diseases Information 11 Churchill DN, Taylor DW, Cook RI, LaPlante P, Barre P, Cartier P, et al. Canadian Clearinghouse (NKUDIC) hemodialysis morbidity study. Am J Kidney Dis 1992;19:214-34. (www.kidney.niddk.nih.gov/kudiseases/pubs/vascularaccess) 12 Mehta S. Statistical summary of clinical results of vascular access —US National Institutes of Health patient resource site procedures for haemodialysis. In: Summer BG, Henry ML, eds. Vascular access for hemodialysis—II. WL Gore, 1991:145-57. Fistula First (http://esrdncc.org/ffcl/for-ffcl-patients/) 13 Ifudu O, Mayer J, Mathew J, Fowler A, Friedman E. Haemodialysis dose is —Explanation of the Fistula First Initiative for patients independent of type of surgically-created vascular access. Nephrol Dial Transplant 1998;13:2311-6. the bmj | 1 November 2014 27 EDUCATION CLINICAL REVIEW

14 Rayner HC, Pisoni RL, Gillespie BM, Goodkin DA, Akiba T, Akizawa T, et al. 28 UK Renal Association. Peritoneal dialysis, 5th edn. 2010. www.renal.org/ Creation, cannulation and survival of arteriovenous fistulae—data from guidelines/modules/peritoneal-dialysis-in-ckd#sthash.2YDHpYfz.dpbs. the Dialysis Outcomes and Practice Patterns Study (DOPPS). Kidney Int 29 Saxena AK, Panhotra BR, Al-Mulhim AS. Vascular access related infections 2003;63:323-30. in hemodialysis patients. Saudi J Kidney Dis Transpl 2005;16:46-51. 15 Endstage Renal Disease National Coordinating Centre. Fistula First 30 European Best Practice Guidelines for Haemodialysis (Part 1): VI.4. Catheter Last—FFCL. 2014. www.esrdncc.org/ffcl/. Treatment of vascular access infection. Nephrol Dial Transplant 16 Lynch JR, Mohan S, McClellan WM. Achieving the goal: results from 2002;17:76-7. the Fistula First Breakthrough Initiative. Curr Opin Nephrol Hypertens. 31 Da Silva AF, Escofet X, Rutherford PA. Medical adjuvant treatment to 2011;20:583-92. increase patency of arteriovenous fistulae and grafts. Cochrane Database 17 UK Renal Association. Vascular access for haemodialysis, 5th edn. Syst Rev 2003;2:CD002786. 2011. www.renal.org/guidelines/modules/vascular-access-for- 32 Dember LM, Beck GJ, Allon M, Delmez JA, Dixon BS, Greenberg A, et haemodialysis#sthash.cfPITA3p.dpbs. al. Effects of clopidogrel on early failure of arteriovenous fistulas for 18 National Institute for Health and Care Excellence. Chronic kidney haemodialysis. JAMA 2008;299:2164-71. disease quality standard. 2011.www.nice.org.uk/guidance/qs5/ 33 Romero A, Polo JR, Morato EG, Garcia Sabrido JL, Quintans A, Ferreiroa JP. chapter/quality-statement-13-dialysis-access. Salvage of angioaccess after late thrombosis of radiocephalic fistulas for 19 Guy’s and St Thomas’ NHS Foundation Trust. Caring for your AV fistula. hemodialysis. Int Surg 1999;71:122-4. 2013. www.guysandstthomas.nhs.uk/resources/patient-information/ 34 Fan Py, Schwab SJ. Vascular access: concepts for the 1990s. J Am Soc kidney/CaringforyourAVfistula.pdf. Nephrol 1992;3:1-11. 20 Oxford University Hospitals NHS Trust. Access for haemodialysis. Part 35 Maya ID, Allon M. Vascular access: core curriculum 2008. Am J Kid Dis 2—looking after your new fistula. 2013. www.ouh.nhs.uk/patient- 2008;51:702-8. guide/leaflets/files/5668Pfistula2.pdf. 36 Turmel-Rodrigues L, Pengloan J, Baudin S, Testou D, Abaza M, Dahdah 21 Oxford University Hospitals NHS Trust, Access for haemodialysis. Part G, et al. Treatment of stenosis and thrombosis in haemodialysis 3—keeping your fistula healthy. 2013. www.ouh.nhs.uk/patient-guide/ fistulas and grafts by interventional radiology. Nephrol Dial Transplant leaflets/files/5669Pfistula3.pdf. 2000;15:2029-36. 22 Van Loon MN, Goorvaerts T, Kessels AGH, van der Sande FM, Tordoir JH. 37 NKF-K/DOQI. Clinical practice guidelines for vascular access: Buttonhole needling of haemodialysis arteriovenous fistulae results guideline 18: when to intervene—primary AV fistulae. Am J Kidney Dis in less complications and interventions compared to rope-ladder 2001;37(Suppl 1):S162. technique. Nephrol Dial Transplant 2010;25:225-30. 38 Rogers NM, Lawton PD. Ischaemic monomelic neuropathy in a non- 23 MacRae JM, Ahmed SB, Atkar R, Hemmelgarn BR. A randomized trial diabetic patient following creation of an upper limb arteriovenous fistula. comparing buttonhole with rope ladder needling in conventional Nephrol Dial Transplant 2006;22:933-5. hemodialysis patients. Clin J Am Soc Nephrol 2012;7:1632-8. 39 Leon C, Asif A. Arteriovenous access and hand pain: the distal 24 Muir CA, Kotwal SS, Hawley CM, Polkinghorne K, Gallagher MP, Snelling hypoperfusion ischemic syndrome. Clin J Am Soc Nephrol 2007;2: P, et al. Buttonhole cannulation and clinical outcomes in a home 175-83. hemodialysis cohort and systematic review. Clin J Am Soc Nephrol 40 Knox RC, Berman SS, Hughes JD, Gentile AT, Mills JL. Distal 2014;9:110-9. revascularization-interval ligation: a durable and effective treatment 25 NKF-K/DOQI. Clinical practice guidelines for vascular access: guideline for ischemic steal syndrome after haemodialysis access. J Vasc Surg 3: selection of permanent vascular access and order of preference for 2002;36:250-5. placement of AV fistulae. Am J Kidney Dis 2001;37(Suppl 1):S143-4. 41 London GM. Left ventricular alterations and end-stage renal disease. 26 Oliver MJ, McCann RL, Indridason OS, Butterfly DW, Schwab SJ. Nephrol Dial Transplant 2002;17:29-36. Comparison of transposed brachiobasilic fistulas to upper arm grafts 42 MacRae JM, Pandeya S, Humen DP, Krivitski N, Lindsay RM. Arteriovenous and brachiocephalic fistulas. Kidney Int 2001;60:1532-9. fistula-associated high-output cardiac failure: a review of mechanisms. 27 Thomson P, Stirling C, Traynor J, Morris S, Mactier R. A prospective Am J Kidney Dis 2004;43:e17-22. observational study of catheter-related bacteraemia and thrombosis 43 Engelberts I, Tordoir JH, Boon ES, Schreij G. High-output cardiac failure in a haemodialysis cohort: univariate and multivariate analyses of risk due to excessive shunting in a haemodialysis access fistula: an easily associations. Nephrol Dial Transplant 2010;25:1596-60. overlooked diagnosis. Am J Nephrol 1995;15:323-6.

ANSWERS TO ENDGAMES, p 34 For long answers go to the Education channel on thebmj.com

STATISTICAL QUESTION PICTURE QUIZ Randomised controlled trials: A hand flexion contracture with progression “within subject” versus 1 Dupuytren’s disease. “between subject” designs 2 Palpable palmar pitting and nodules, which progress to cords Statements a, b, and c are all true. that cause flexion contractures of the small joints of the hand. 3 Inclusion cyst, ganglion, trigger finger, camptodactyly, ANATOMY QUIZ trauma, and soft tissue sarcoma. 4 Fasciotomy (closed or open), fasciectomy (segmental, The larynx limited, or radical), and dermofasciectomy aimed at A: Right arytenoid cartilage correcting the flexion deformities are the main surgical B: Left pyriform fossa treatments. C: Trachea 5 Yes. Recent innovation has resulted in the use of a D: Left vocal cord collagenase injection to break down the diseased collagen E: Right laryngeal ventricle that is causing contracture. Early evidence shows that recurrence rates are similar to those of surgery at three years. F: Right false vocal cord

28 1 November 2014 | the bmj