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Ischemic complications after endovascular abdominal repair

Thomas S. Maldonado, MD, Caron B. Rockman, MD, Eric Riles, BA, Diah Douglas, MD, Mark A. Adelman, MD, Glenn R. Jacobowitz, MD, Paul J. Gagne, MD, Matthew N. Nalbandian, MD, Neal S. Cayne, MD, Patrick J. Lamparello, MD, Stephanie S. Salzberg, MD, and Thomas S. Riles, MD, New York, NY

Objectives: Limb and pelvic are known complications after endovascular abdominal aortic aneurysm repair (EVAR). The objective of this paper is to present our experience with the incidence, presentation, and management of such complications. Methods: Over 9 years 311 patients with aortic aneurysms underwent EVAR. A retrospective review identified 28 patients (9.0%) with ischemic complications. Results: Among 28 patients with ischemic complications, 21 had lower extremity ischemia and 7 had pelvic ischemia: Of the 21 patients with lower extremity ischemia, 15 had limb .(2 ؍ and spinal cord (n ,(2 ؍ buttock (n ,(4 ؍ colon (n occlusions (71.4%), 3 due to embolization (14.7%) and 3 the result of common femoral thromboses (14.7%). Limb ,(5 ؍ intermittent claudication (n ,(3 ؍ rest pain (n ,(6 ؍ occlusions were manifested as severe acute arterial ischemia (n ,(4 ؍ Limb occlusions were managed with thrombectomy and placement (n .(1 ؍ and decreased femoral pulse (n and expectant management ,(1 ؍ eventual explantation because of persistent endoleak (n ,(7 ؍ femorofemoral bypass (n The 3 patients with occlusions managed expectantly all had intermittent claudication, which has subsequently .(3 ؍ n) improved. In the 6 patients with lower extremity ischemia due to embolization or common femoral artery injury presentation was acute, and was performed, followed by femoral artery and patch or placement of an interposition graft. One patient who had a prolonged postoperative course including cardiac arrest subsequently required distal bypass and ultimately above- knee amputation. Among the 7 patients with pelvic ischemia, 2 patients had unilateral hypogastric artery embolization before the original surgery. Among the patients with colonic ischemia, 3 were seen immediately postoperatively, and required colectomy and colostomy. Two patients who required urgent colectomy subsequently had multiple organ failure, and died in the perioperative period. One patient had abdominal pain 1 week after surgery, which was managed with bowel rest, with subsequent improvement. In 2 patients spinal cord ischemia developed immediately after surgery, w hich resulted in persistent paraplegia. Buttock ischemia developed in 2 patients, 1 of whom required fasciotomy because of gluteal compartment syndrome, and had transient renal failure. Conclusions: Ischemic complications are not uncommon after EVAR, and may exceed the incidence with open surgical repair. Limb ischemia is most often a result of limb occlusion, and can be successfully managed with standard interventions. Pelvic ischemia often results from atheroembolization despite preservation of hypogastric arterial circulation. Colonic and spinal ischemia are associated with the highest morbidity and mortality. (J Vasc Surg 2004;40:703-10.)

Pelvic ischemic complications after open infrarenal aor- Indeed, ischemic complications after EVAR occur in 3% to tic reconstruction occur in 1% to 2% of patients, with an 10% of patients.8-17 Mechanisms purported to contribute associated mortality rate greater than 40%.1-3 Likewise, to pelvic ischemia include interruption of hypogastric arte- lower extremity ischemia after aortic reconstructions, often rial circulation and atheroembolization, whereas lower ex- referred to as “trash foot” is a well-recognized result of tremity ischemia after EVAR appears to be more commonly atheroemboli, and occurs in 1% to 5% of patients.4-7 associated with limb occlusion.9,12,13 The purpose of this The advent of endovascular abdominal aortic aneurysm study was to examine the incidence, management, and repair (EVAR) has led to a decrease in postoperative mor- outcome of pelvic and lower extremity ischemia after bidity, shorter hospital stay, and quicker recovery time. EVAR. Nevertheless, EVAR continues to be burdened with the same ischemic complications seen with open aortic surgery. METHODS From the Division of Vascular Surgery, Department of Surgery, New York A retrospective review was performed of a prospectively University School of Medicine. compiled database of all EVAR procedures performed at Competition of interest: none. Presented at the Fifty-seventh Annual Meeting of the Society for Vascular New York University Medical Center. From 1994 through Surgery, Anaheim, Calif, Jun 3, 2004. 2003, 311 EVAR procedures were attempted. The first 46 Reprint requests: Thomas S. Maldonado, MD, NYU Medical Center, 530 procedures (14.8%) were performed during approved clin- First Ave, Ste 6F, New York, NY 10016 (e-mail: Thomas.maldonado@ ical trials, including the Endovascular Technologies trial med.nyu.edu). and the Excluder trial (W. L. Gore & Associates). The 0741-5214/$30.00 Copyright © 2004 by The Society for Vascular Surgery. remaining 265 procedures (85.2%) were performed after doi:10.1016/j.jvs.2004.07.032 approval of the devices by the US Food and Drug Admin- 703 JOURNAL OF VASCULAR SURGERY 704 Maldonado et al October 2004

Table I. Lower extremity ischemic complications

Limb occlusion CFA injury Embolus Total

Leg ischemia 15 3 3 21 Onset Early (Ͻ30 days postoperative) 9 3 3 15 Late (Ͼ30 days postoperative) 6 0 0 6 Presentation Loss of pulse 1 2 1 4 Claudication 5 0 0 5 Rest pain 4 0 0 3 Cool “threatened” limb 5 1 2 8 Treatment Stent/PTA 4 0 0 4 Femorofemoral bypass 7 0 0 7 Femoral endarterectomy 0 2 0 2 Thrombectomy 0 3 3 3 Interposition graft 0 1 0 1 Expectant management 3 0 0 3 Explantation 1 0 0 1 Outcome Amputation 0 1* 0 1 Limb salvage 15 2 3 20

CFA, Common femoral artery; PTA, percutaneous transluminal angioplasty. istration (FDA) in 1999. Devices used after FDA approval appropriate, continuous variables were analyzed with the included the Ancure (Guidant), AneuRx (Medtronic), Ex- 2-tailed Student t test. P Յ .05 was considered statistically cluder (W. L. Gore & Associates), and Zenith (Cook) significant. grafts. In all cases endovascular grafts were deployed below the renal , with suprarenal or infrarenal fixation, RESULTS depending on the device, and distally in either the common Endovascular repair was attempted in 311 patients, 44 iliac artery or external iliac artery, depending on the extent women (14.1%) and 267 men (85.9%), with a mean age of of aneurysmal disease. In cases in which hypogastric arteries 72.2 years (range, 58-93 years). In 6 patients (all with were coiled, embolization was routinely staged to precede EVT/Ancure) conversion to open repair was required be- EVAR by 1 or 2 days. Two patients underwent bilateral cause of device malfunction or difficulty during deploy- hypogastric coil embolization, with an interval of 2 to 3 ment (98.1% success rate). Mean aortic aneurysm diameter weeks between embolizations. Coils were placed in the was 5.8 cm (range, 4.7-8 cm). Ancure grafts were placed in internal iliac artery through either the ipsilateral or con- 238 patients (76.5%), Excluder grafts in 30 patients (9.6%), tralateral approach with a variety of catheters. Care was AneuRx grafts in 28 patients (9.0%), and Zenith grafts in 15 taken to not place coils past the proximal internal iliac artery patients (4.8%). Fourteen endografts (4.5%) were tube so as to preserve pelvic collateral circulation. EVAR was configured, and 297 (96.1%) were bifurcated devices. performed only in patients with asymptomatic disease, with Among 28 patients with ischemic complications, 21 had the exception of 1 patient in whom embolism was known to lower extremity ischemia and 7 had pelvic ischemia: colon be occurring preoperatively. (n ϭ 4), buttock (n ϭ 2), and spinal cord (n ϭ 2). Four of Significant pelvic ischemia was defined as buttock 28 ischemic complications occurred in women (14.3%). necrosis, as well as colonic or spinal ischemia. Buttock Nine of 28 patients (32.1%) had aneurysmal common iliac claudication was not considered. Lower extremity isch- arteries. Ischemic complications occurred in patients with emia was stratified as limb occlusion, common femoral the following endografts: Zenith (n ϭ 1, 3.6%)), Excluder artery injury, or atheroembolism. There were no bilateral (n ϭ 1, 3.6%), AneuRx (n ϭ 2, 7.1%), and Ancure (n ϭ 24, limb occlusions. In 311 EVAR procedures, 28 patients 85.7%). The only perioperative deaths occurred in 2 of 7 had pelvic or lower extremity ischemic complications. patients with pelvic ischemia (28.6%; P Ͻ .0001). No This group formed the focus of our study. The follow-up patients with limb ischemia died as a result of a complica- period ranged from 2 to 72 months (mean, 22.5 tion. months). Twenty-four of 311 patients (7.7%) were lost Lower extremity ischemic complications. A sum- to follow-up. An office visit, including history and phys- mary of lower extremity ischemic complications is pre- ical examination, and computed tomography was made sented in Table I. Of 21 patients with lower extremity at 1, 6, and 12 months, and yearly thereafter. ischemia, this complication was the result of limb occlusion Statistical analysis was performed with the SPSS statis- in 15 patients (71%), atheroembolization in 3 patients tical software package. Proportional data were analyzed (14.7%), and common femoral artery thrombosis in 3 pa- with the ␹2 test, the Fisher exact test was used where tients (14.7%). JOURNAL OF VASCULAR SURGERY Volume 40, Number 4 Maldonado et al 705

Table II. Pelvic ischemia after endovascular abdominal aortic aneurysm repair

Colon Spinal Buttock Total

Pelvic ischemia 4 2* 2 7 Presentation Acute (Ͻ30 days postoperative) 4 2 2 7 Late (Ͼ30 days postoperative) 0 0 0 Management Colon resection 3 0 0 3 Colostomy 3 0 0 3 Fasciotomy 0 0 1 1 Expectant 1 2 1 3 Outcome Death 2 1 0 3 Paralysis 0 1 1 2 Recovery 2 0 1 3

*One patient with spinal ischemia had concomitant buttock ischemia.

Limb occlusions manifested with pain and parasthesia tion, and subsequently required above-knee amputation of (n ϭ 5), rest pain alone (n ϭ 4), intermittent claudication the limb. (n ϭ 5), and decreased femoral pulse as the sole finding Pelvic ischemic complications. A summary of pelvic (n ϭ 1). No patient had motor deficits. Limb occlusions ischemic complications is presented in Table II. The single were managed according to surgeon preference, as follows: patient to undergo EVAR for treatment of an embolizing 4 patients underwent thrombectomy and stent placement, aneurysm had extensive atheroembolic ischemia to the 7 patients underwent femorofemoral bypass, 1 graft was colon and soft tissues, which required colectomy, and eventually explanted because of persistent type I endoleak, massive debridement and reconstruction of the anterior and 3 patients were managed expectantly. The 3 patients abdominal wall. managed expectantly all had intermittent claudication, Anatomic characteristics of patients in whom pelvic which has subsequently improved. In 14 of 15 patients with ischemia developed after EVAR are presented in Table III. limb occlusions unsupported endografts (Ancure) were Among the 7 patients with pelvic ischemia, 2 had unilateral implanted. Five limb occlusions in patients with Ancure hypogastric artery embolization before the original surgery devices in place had been stented a priori, because of kinked (colon ischemia, n ϭ 1; buttock ischemia, n ϭ 1). Four or stenosed limbs noted at the initial EVAR. One patient patients had a patent inferior mesenteric artery before with a supported endograft (AneuRx) had limb occlusion at EVAR; colon ischemia developed in all 4 patients. Three 6 months post-EVAR. In 4 of 15 occluded limbs (26.7%) patients had small distal necks, and 2 patients had thrombus devices were deployed in the external iliac artery (P ϭ in the proximal neck. .206). Average limb diameter of the 15 occluded limbs was Among 4 patients with colonic ischemia, 3 presented 13.2 mm. immediately postoperatively, and required colectomy and In all 3 patients with atheroembolization resulting in colostomy. In 2 patients who required urgent colectomy lower extremity ischemia the diagnosis was made early after multiple organ system failure developed, and they died in surgery and was treated with embolectomy. One patient the perioperative period. Another patient had abdominal had an absent pedal pulse 6 hours postoperatively. Two pain 1 week after surgery. Ischemic colitis was confirmed at patients’ limbs were noted to be markedly ischemic at colonoscopy, was managed with bowel rest, and improved. surgery, and a diagnosis was made of emboli to the super- Hypogastric artery embolization was performed in 1 ficial femoral artery and tibioperoneal trunk. In 1 patient patient with colon ischemia. EVAR in this patient was the underlying superficial femoral artery lesion was treated complicated by a detached limb, which necessitated con- with a stent after embolectomy. version to an aortouniiliac device and coiling of the right Three patients had lower extremity ischemia, diagnosed in common and internal iliac arteries in addition to a fem- the immediate postoperative period, as a result of common oral-femoral bypass. The left internal iliac artery was femoral artery injury and thrombosis. One required a bypass patent and perfused retrograde after femorofemoral by- interposition graft, because of severe dissection in the com- pass. In addition to colonic necrosis requiring urgent mon femoral artery. Two patients underwent common fem- colectomy, Fournier gangrene developed in this patient, oral endarterectomy and patch angioplasty. One of these which could also be attributed to atheroemboli. Subse- patients had cardiac arrest on the first postoperative day, at quently multiple organ system failure developed, and the which time both lower extremities were thrombosed. After patient died in-hospital. unsuccessful thrombectomy a distal bypass was performed, In 2 patients spinal cord ischemia developed immedi- which subsequently also became thrombosed. This patient ately after surgery, resulting in persistent paraparesis in was presumed to have an underlying hypercoagulable condi- both patients.15 One of these patients underwent conver- JOURNAL OF VASCULAR SURGERY 706 Maldonado et al October 2004

Table III. Anatomic characteristics of patients with pelvic ischemia after EVAR

Ischemic Previous Iliac Iliac Neck Sac Hypogastric IMA Patient complication colectomy aneurysm thrombus thrombus thrombus embolus patent Death

1 Spine, buttock No No Yes No Yes No No No 2 Spine No Yes Yes Yes Yes No No No 3 Colon, abdominal No No No No Yes No Yes Yes wall 4 Colon, Fournier No No No Yes Yes Yes Yes Yes gangrene 5 Colon Yes No No No Yes No Yes No 6 Colon No No Yes No Yes No Yes No 7 Buttock No Yes Yes No Yes Yes Yes No

EVAR, Endovascular abdominal aortic aneurysm repair; IMA, inferior mesenteric artery. sion to open repair when the Ancure graft failed to com- most AAAs are now treated with this minimally invasive pletely unsheath. Postoperatively this patient had transient procedure. The resultant decreased postoperative cardio- elevation in creatine phosphokinase (CPK) concentration, pulmonary morbidity and hospital cost is of clear benefit. and patchy areas of left buttock skin necrosis, which re- However, this is tempered by the ischemic complications solved. The other patient underwent successful EVAR, but that persist in a subset of patients. severe paraparesis and bladder dysfunction developed. Both Our finding of 2.25% pelvic ischemic complications is patients underwent magnetic resonance imaging imaging consistent with similar reports in the literature,13,18 and of the spine, which confirmed atheroembolization to the appears to equal that described for open repair, approxi- conus medullaris. mately 1% to 2%.1-3 Dadian et al13 reported a 2.9% inci- In an additional patient severe global buttock ischemia dence of colon ischemia in 8 of 278 patients after EVAR. developed, and required fasciotomy to treat gluteal com- Half of these patients (n ϭ 4) required colectomy, and partment syndrome. This patient was morbidly obese subsequently 3 of these patients died. In our series, 7 of 28 (weight, 350 lb) and had transient renal failure as a result of ischemic complications resulted in pelvic ischemia. Three of buttock ischemia. The anatomy was suboptimal in that 4 patients who had colonic ischemia required urgent colec- there was a short angulated neck; however, other comorbid tomy, and 2 died. The diagnosis of colon ischemia in our conditions precluded open repair. EVAR required preop- study was based entirely on clinical presentation. Thus, erative hypogastric artery embolization and limb deploy- while our results confirm that clinically apparent colonic ment in the external iliac artery, because of a 40-mm ischemia after EVAR or open repair is often lethal, we may common iliac artery aneurysm. Pathologic analysis failed to have underestimated its true incidence. Ernst et al19 pro- show evidence of thrombosis or embolization to the glu- spectively evaluated all patients after open aortic recon- teus muscle, making the ischemic complication more likely structions with routine colonoscopy, and found that the a result of interruption of the internal iliac artery.17 incidence of ischemia increases to 6% from the well- Effect of internal iliac artery embolization on isch- established incidence of 1% to 2%. The spectrum of isch- emic complications (Fig). One or both hypogastric arter- emia in the colon when evaluated at endoscopy ranges from ies were either coiled (n ϭ 41) or inadvertently covered mild edema to pseudomembranes. In our study the 1 (n ϭ 2) in 43 patients undergoing EVAR (13.8%). In 2 patient with colon ischemia seen 10 days post-EVAR with patients bilateral hypogastric arteries were coiled before abdominal pain was fortunate to have only patchy ery- EVAR; pelvic ischemia did not develop in either patient. thema, which was successfully managed with bowel rest Ischemic complications developed in 16.3% of patients alone. with any sacrificed hypogastric artery, compared with 8.0% All but one of the EVAR procedures in our study was of patients in whom both hypogastric arteries were pre- performed in patients with asymptomatic disease. One pa- served (P ϭ .091). Pelvic ischemia occurred in 4.7% of tient who had “trash feet” and elevated creatinine concen- patients with hypogastric embolization, compared with tration as a result of atheroemboli from an AAA underwent 1.9% of those without hypogastric embolization (P ϭ .26). EVAR. Widespread atheroembolism to the pelvis and ab- In 42 of the 43 patients in whom a hypogastric artery was dominal wall subsequently developed, and the patient died occluded limbs were deployed in the external iliac artery. postoperatively. Treatment of embolizing abdominal aneu- Limb ischemia occurred in 11.6% of patients with hypogas- rysms with endovascular is often considered exceed- tric coil embolization, compared with 6.1% of patients ingly high risk, because of the well-founded concern that without embolization (P ϭ .19). the unstable plaque or thrombus will dislodge as a result of catheter and wire manipulations before deployment. This is DISCUSSION likely the mechanism that resulted in such widespread As endovascular aortic aneurysm repair has gained ac- atheroemboli and pelvic ischemia in our patient. Neverthe- ceptance by the medical community and the public alike, less, Shames et al20 have reported promising results in their JOURNAL OF VASCULAR SURGERY Volume 40, Number 4 Maldonado et al 707

In our study we staged coil embolization and EVAR by 1 or 2 days. There is no consensus regarding the appropri- ate staging interval between embolization of a single hypo- gastric artery and EVAR. Indeed, some authors have pro- posed that simply covering the hypogastric artery during EVAR does not increase the risk for endoleak or ischemia and averts the need for a preoperative embolization proce- dure.26 Nevertheless, most authors agree that when bilat- eral hypogastric artery embolization is planned, EVAR should be delayed by 2 to 4 weeks.13,18,23 Interruption of bilateral internal iliac arteries has also been reported to be free from colon ischemia. Englke et al27 reviewed 16 patients with bilateral embolization before Internal iliac artery interruption and ischemic complications after EVAR, and found buttock claudication and sexual dysfunc- endovascular abdominal aortic aneurysm repair. Note: 16.3% of all tion to be the only adverse events. Others are more wary of patients treated with coil embolization had an ischemic event, interrupting important pelvic collateral vessels in the setting compared with 8.0% of patients who underwent internal iliac artery of EVAR.14,18,22,28-30 Leyden et al18 report 1 of 21 pa- embolization (P ϭ .091). tients (4.3%) with colonic ischemia after hypogastric artery embolization. Likewise, Karp et al31 reviewed 24 patients with either coiled or unintentional covering of a hypogas- treatment of embolizing arterial lesions with stent grafts. tric artery during EVAR, and found 3 patients (12%) in None of the 8 patients treated with covered stents in their whom colon ischemia developed, requiring resection in 1 series had atheroembolic complications as a result of the patient. Our study found 2 of 43 patients (4.3%) with procedure. Likewise, Dougherty et al21 successfully im- hypogastric arteries either covered or coiled in whom pelvic planted covered stents in 2 patients with embolizing ather- ischemia developed. This was in contrast to 5 of 268 oma in the infrarenal without causing further embo- patients (1.9%) with intact iliac arteries (P ϭ .26). These lization. results suggest that coil embolization of hypogastric arter- The 2 patients in our study with spinal ischemia after ies before EVAR does not predispose to pelvic ischemia. EVAR have been previously presented as case reports, and Rather, the cause of pelvic ischemia would appear to be had permanent paraplegia as a result of atheroemboli to the more consistent with atheroemboli. All 7 patients with conus medullaris diagnosed at magnetic resonance imag- pelvic ischemia had copious thrombus in the aneurysm sac. ing.15 They accounted for 2 of 28 patients (7.1%) with All but 2 patients had thrombus in the neck or access ischemic complications, for an overall incidence of 0.64%. vessels, and in 1 of the 2 embolization was occurring Others have reported a similarly low incidence of spinal preoperatively. In 3 of 7 patients with pelvic ischemia in our ischemia after EVAR.11,18 A review of the European Col- study widespread pelvic ischemia developed, to the colon laborators on Stent Graft Techniques for Abdominal Aortic and abdominal wall, the colon and perineum, and the spine Aneurysm Repair (EUROSTAR) registry identified6of and buttock, respectively. Dadian et al13 documented athe- 2862 patients (0.21%) with spinal cord ischemia.11 There roemboli in pathologic specimens from 4 of 8 patients with was a significant correlation between coil embolization of colon ischemia after EVAR. They also report that wide- the hypogastric or lumbar arteries (P Ͻ .029) and spinal spread atheroemboli is associated with a poorer prognosis cord ischemia in that study. than isolated colon ischemia.13 Indeed, in our series of This significance of hypogastric artery occlusion for patients with pelvic ischemia the 2 patients who died had development of pelvic ischemia has been a subject of some widespread atheroembolism after EVAR. controversy. The most common sequela after interruption Other predisposing factors to pelvic ischemia might of hypogastric arteries as an adjunct to EVAR appears to be include inadequate mesenteric collateral vessels, either as a development of buttock claudication. The incidence of result of intrinsic disease or iatrogenic (ie, after colectomy). buttock claudication ranges from 11% to 50% after coil We did not assess the status of the inferior mesenteric artery embolization of one or both internal iliac arteries.15,18,22-25 in most patients, nor were we able to evaluate the arch of Colonic ischemia, however, appears to be much less com- Riolan or marginal artery collateral vessels, but found that 5 mon after interruption of the hypogastric circulation. of 7 patients with pelvic ischemia had patent inferior mes- Mehta et al23 reviewed a series of 154 patients in whom enteric arteries before EVAR. Likewise, in only 1 patient hypogastric arteries were interrupted as part of either open with previous colectomy did mild self-limited colonic isch- (n ϭ 47) or endovascular (n ϭ 107) repair, and found no emia develop. patients with ischemic colitis that required laparotomy or Lower extremity ischemia after EVAR is most fre- buttock necrosis. Those authors staged embolization and quently a result of limb occlusion, although atheroemboli- EVAR in some, but not all, patients, and conclude that zation has also been reported. A case series of early vascular hypogastric embolization as part of EVAR can be done complications after EVAR by Aljabri et al 9 demonstrated a safely without significant risk for severe pelvic ischemia. 9.6% incidence of lower extremity ischemia (4 limb occlu- JOURNAL OF VASCULAR SURGERY 708 Maldonado et al October 2004 sions, 1 embolization). A review of the literature by the endograft, and always identified an underlying kink or steno- same authors found a mean incidence of lower extremity sis. Seven patients underwent femorofemoral bypass, and 3 ischemia of 5.1% (range, 0.6%-9.9%) at short-term follow- patients were managed expectantly. Carroccio et al12 reported up.9 The EUROSTAR prospective registry identified 18% similar management of limb occlusion in their series, although of patients requiring secondary intervention for treatment they used thrombolysis rather than thrombectomy. Eighteen of limb occlusions at more than 12 months after EVAR.32 of 26 patients (69.2%) in that study required interventions, In our study we identified 21 patients (6.75%) with and the remaining 8 patients (31.8%) were managed expect- lower extremity ischemia after EVAR: 15 limb occlusions antly. (4.5%), 3 embolizations (0.9%), and 3 common femoral Thromboembolism to the lower extremity during EVAR injuries (0.9%). Complex aortoiliac anatomy, including tor- may be more common than previously appreciated, albeit tuous, narrow, and calcified access vessels, as well as narrow subclinical. Using an ultrasound-based method to detect distal necks, have all been proposed as harbingers of limb lower extremity embolization, Thompson et al34 detected 12 occlusion. Carroccio et al examined anatomic and device- significantly greater microemboli in endovascular compared related causes of limb occlusion in a series of 351 patients with conventional open repair of AAA. In addition, in 3 of 20 (702 graft limbs at risk). Thrombosis occurred in 26 of the patients (15%) who underwent EVAR and had high particu- 702 limbs at risk (3.7%), and was associated with smaller late counts at ultrasound scanning transient petechiae to the Յ ϭ limb diameter ( 14 mm; P .3) and extension into the feet developed. The incidence of clinically apparent macroem- ϭ external iliac artery (P .01). These authors did not find a boli to the lower extremities is approximately 2%.35 Our study significant association between limb thrombosis and device identified 3 patients (0.09%) with atheroemboli that caused type. This may be explained by the relatively low number of lower extremity ischemia. These were all successfully treated, Ancure devices (n ϭ 8) in their series. Others have shown with thrombectomy and stent placement in 1 patient for that limb occlusion is indeed device-related. Ouriel et al33 treatment of an underlying superficial femoral artery stenosis. examined device-specific complications after EVAR, and In summary, ischemic complications after EVAR oc- found that limb occlusions occurred most often with the curred in 9% of patients in our series. Pelvic ischemia often unsupported Ancure device (11.6% Ϯ 4.6% at 12 months; results from atheroembolization, despite preservation of P ϭ .009). Another review by Parent et al16 of 67 patients hypogastric arterial circulation. The overall ischemic com- with Ancure devices in place demonstrated a 13.4% rate of plications after interruption of hypogastric arteries before limb occlusion or stenosis. Subgroup analysis in that study EVAR was 16.3%, compared with 8% in intact hypogastric demonstrated that when limbs were primarily stented at ϭ EVAR they were free from subsequent limb dysfunction. In arteries (P .091). This approaches statistical significance, our series the Ancure device was used most often (n ϭ 238, and is likely due to limb deployment in the external iliac 76.5%). 14 of 15 patients with limb occlusions had Ancure artery in those patients with coiled hypogastric arteries. unsupported endografts in place. Our seemingly lower Colonic and spinal ischemia are associated with the highest incidence of limb thrombosis (4.5%), compared with the morbidity and mortality. Limb ischemia is most often a experience of Ouriel et al33 and Parent et al,16 may be result of limb occlusion, and can be successfully managed attributed to the fact that surgeons at our institution have with standard interventions. a low threshold for preemptively stenting iliac limbs at EVAR. Nonetheless, 5 of the limb occlusions in patients REFERENCES with Ancure devices in place had been stented a priori, because of kinked or stenosed limbs noted at the initial 1. Brewster DC, Franklin DP, Cambria RP, Darling RC, Moncure AC, LaMuraglia GM, et al. Intestinal ischemia complicating abdominal EVAR. Nevertheless, the more cumbersome and bulkier aortic surgery. Surgery 1991;109:447-54. design of the Ancure endograft may contribute to higher 2. Diehl JT, Cali RF, Hertzer NR, Beven EG. Complications of abdominal risk for atheroembolization. In particular, the extra manip- aortic reconstruction. 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DISCUSSION Dr Michael L. Marin (New York, NY). Embolization and Several years ago Dr Timothy Chuter alerted us to the problem of hypoperfusion have always plagued conventional vascular surgery, complex aortic aneurysm thrombus and the possibility of increased and it’s not surprising that any newcomer to this field will suffer risk for embolization from EVAR. Specifically, he described multiple similar consequences. Ischemic complications after EVAR have channels in the aneurysm clot that may be predisposed to emboliza- been recognized and described since Parodi first told us about this tion with the passage of endoluminal devices. Did the authors en- procedure in 1990. counter this sort of pathologic finding in any of their patients with Dr. Maldonado and colleagues report today their findings in either mild or massive forms of ischemia? 28 patients in whom postoperative ischemia developed after EVAR In our experience with EVAR at Mount Sinai, which now from a 9-year experience treating 311 patients. I’d like to ask the includes over a thousand patients, common femoral artery authors several questions to enhance our understanding of this disease is common, and perhaps more common than is often complex problem. described. In fact, at the end of most procedures reconstruction Ischemic complications following all vascular surgery proce- of the common femoral artery by one means or another is going dures, EVAR not excluded, surely are not limited to the colon, to invariably be required. Did the authors use the highly fash- spine, pelvis, and lower extremities; rather, renal artery occlusions ionable percutaneous EVAR technique in any of their patients, and embolizations, and proximal embolization from aneurysmal which would preclude the ability to recognize the types of vessel thrombus into the suprarenal components of the aorta resulting in injury commonly seen after EVAR and thereby prevent the arm ischemia, stroke, and even MI have been reported. Could the ischemic sequelae? authors tell us a little about these other ischemic events that may Your description of severe and devastating colon and spinal have occurred in their 311 patients so we’d have a broader picture cord ischemia in association with gluteal gangrene is a sadly familiar of the problem of ischemia after EVAR. complication, which anybody who has been involved in this field JOURNAL OF VASCULAR SURGERY 710 Maldonado et al October 2004

for a number of years has seen. We have not seen this problem since MRA I showed you for the patient with embolization preopera- the early portions of our experience, and we’ve attributed this to tively may have had some of that, but is more difficult to interpret. greater personal experience and more facile devices that are less We do not have any experience with the percutaneous en- bulky. Are the massive forms of ischemia of the pelvis that you dograft technique. However, I agree that repair of the common described to us today a product of your earliest experience, or is it femoral artery is occasionally required in our experience, as well. something you believe is a continuing problem in the treatment of Our experience is indeed mostly with the Ancure device, a patients with EVAR? bulkier device, and surely that may have had some role in Finally, could you briefly clarify your recommendations, based predisposing these patients to ischemic complications. How- on your experiences, for management of coexisting iliac artery ever, there were 2 patients among the 7 with pelvic ischemia aneurysms in EVAR. More specifically, how do you time your who had other devices implanted. So I believe that this is a selective internal embolizations? Do you stage bilateral emboliza- problem that will persist despite the Ancure device being no tions to perhaps reduce the risk for pelvic ischemia? And do you do longer available. Endovascular manipulation of catheters, wires, preemptive flexible sigmoidoscopy to actually find the problem and devices within a thrombin-laden sac will always pose a before it can become a more significant clinical issue? certain risk for embolization, regardless of lower profile and less Dr Thomas S. Maldonado. This study did not address the incidence of renal or suprarenal cumbersome devices. ischemic complications. However, I will tell you that we had no Insofar as our treatment of common iliac artery aneurysms and instances of stroke, upper extremity ischemia, or massive MI that we our staging of coil embolizations, we tend to stage the emboliza- can attribute to an atheroembolic cause. Insofar as the renal ischemia, tion at least 2 days before EVAR. In patients with bilateral coil in the event that a renal artery is inadvertently covered we have always embolizations we usually wait approximately 2 weeks between coil been successful in stenting the renal artery open. Atheroembolization embolizations. In addition, in patients at increased risk for isch- to the renal artery, however, may well occur. No instances of acute emia (eg, previous colectomies or bilateral hypogastric emboliza- renal failure or infarct occurred in our series; however, it would be tions) I think it advisable to interrogate the mesenteric collateral interesting to review postoperative CT and or renal function tests to circulation at . Finally, given the 2.25% incidence of identify any subclinical sequelae of embolization. pelvic ischemia after EVAR, we do not use routine preemptive We did not see any CT characteristics, such as flow channels sigmoidoscopy. However, in theory this may surely help in earlier within the thrombus, that might help predict embolization. The diagnosis and intervention.