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Strategies to Tackle Unrecognized Bilateral Renal Artery Occlusion After Endovascular Aneurysm Repair
Case Reports Strategies to Tackle Unrecognized Bilateral Renal Artery Occlusion After Endovascular Aneurysm Repair John Adu,1 Nicholas J. Cheshire,1,2 Celia V. Riga,1,2 Mohamad Hamady,3 and Colin D. Bicknell,1,2 London, United Kingdom
Background: Unintentional renal artery occlusion after endovascular aortic aneurysm repair (EVAR) is an uncommon phenomenon. The sequelae from this specific complication are severe; consequently, the topic of renal artery coverage is a pertinent issue. We present a case series of patients undergoing EVAR with unintentional renal artery coverage, review the treatment options available, and suggest a treatment algorithm for this scenario based on the evidence. Methods and Results: We report four patients who were found to have renal artery occlusion after EVAR detected up to 5 weeks postoperatively. Renal revascularization was achieved using endovascular renal artery stenting in two patients, and open hepato-spleno-renal bypass in the remaining two cases. Treatment strategies used led to symptom resolution and recovery of renal function in all cases. Conclusions: Both open and endovascular techniques may be used as procedures to treat this conditiondthe choice of procedure is primarily determined by accessibility of the renal orifice.
Unintentional renal artery occlusion after endovascular aortic aneurysm repair (EVAR) is an uncommon phenomenon. However, as operators performing endovascular intervention have become more ambitious, shorter and more angulated aortic neck configurations are being tackled with standard stent grafts, increasing the risk of renal artery coverage/occlusion. The sequelae from this specific complication are severe; consequently, the topic of renal artery coverage is a pertinent issue.
1 Imperial Vascular Unit, St Mary’s Campus, Imperial College Healthcare NHS Trust, London, UK. 2 Department of Surgery and Cancer, Imperial College London, London, UK. 3 Department of Interventional Radiology, St Mary’s Campus, Imperial College Healthcare NHS Trust, London, UK. Correspondence to: Colin D. Bicknell, MD, FRCS, Vascular Secretaries Office, Waller Cardiac Building, St. Mary’s Hospital, Praed Street, London W2 1NY, UK; E-mail: [email protected]
Ann Vasc Surg 2012; 26: 1127.e1e1127.e7 DOI: 10.1016/j.avsg.2012.02.018 Ó Annals of Vascular Surgery Inc.
Techniques for renal artery salvage as an emergency maneuver during EVAR are fairly well described.1e3 However, when renal artery occlusion is unrecognized, presenting hours, days, or weeks after EVAR, management strategies are unclear. The aim of this article is to present a case series of patients undergoing EVAR with unintentional renal artery coverage, review the treatment options available, and suggest a treatment algorithm for this scenario based on the evidence. All patients in our series were initially treated at their local hospital and later transferred to our tertiary referral unit.
CASE REPORT 1 A 78-year-old man presented to his local hospital with sudden-onset loin pain. Urgent computed tomography (CT) angiography demonstrated a ruptured infrarenal abdominal aortic aneurysm (AAA) with a significantly angulated proximal neck. He underwent emergency endovascular aneurysm repair receiving local anesthesia. An aortouniiliac Medtronic Endurant stent (Santa Rosa, 1127.e1
1127.e2 Case reports
Annals of Vascular Surgery
Fig. 1. (A, B) Angiograms acquired before chimney stent placement demonstrating renal vessel filling via a small channel between the main body of the stent graft and the aorta. (C) Selective cannulation of the left renal
artery. (D) Postestent insertion completion angiogram confirming patency of the left renal artery and its branches. (E) Subsequent reconstructed computed tomography angiogram.
CA) was deployed via the right groin, followed by limb extension to the right common iliac artery (CIA) and Amplatzer 22-mm device placement to occlude the proximal left CIA. The postdeployment angiogram demonstrated a type 1a endoleak, which was managed with a proximal aortic extension cuff. Completion angiogram confirmed exclusion of the aneurysm, no endoleak, and perfusion of both renal arteries. A right-to-left femorale femoral crossover graft was then constructed using an 8mm Dacron graft. He was subsequently transferred to our institution, necessitated by intensive care unit (ICU) bed unavailability at his local hospital. Although he appeared well initially postoperatively, worsening oliguria, significant respiratory compromise, and rising intra-abdominal compartment pressures mandated urgent laparostomy formation with Bogota bag closure at 18 hours after EVAR. After this, he became anuric. Subsequent CT scanning demonstrated coverage of both renal arteries, with some left renal vessel filling via a small channel between the main body of the stent graft and the aorta. He underwent urgent angiography and chimney stent placement. Access was obtained from the left brachial artery via a 6-F sheath. A 0.035-inch Terumo wire (Terumo Europe, Leuven, Belgium) was passed between the main body of the stent graft and the aortic wall into the left renal artery and exchanged for a 0.035-inch Amplatz
wire (Cook Medical, Bloomington, IN). A 7-mm balloon was inflated between the aorta and the main of the body device to lift the fabric of the stent away from the aortic wall. Three 6 22-mm Advanta covered stents (Atrium, Hudson, OH) were subsequently deployed to bridge the gap between the aorta and the left renal artery. Postoperative angiograms demonstrated good stent position, perfusion of the left renal artery, and no evidence of an endoleak (Fig. 1). There was no attempt made to salvage the right renal artery because this kidney was most likely ischemic, and the patient was too unstable for bilateral prolonged attempts at renal salvage. During his 62-day ITU stay, he underwent closure of laparostomy defect using a Permacol porcine collagen mesh (Covidien PLC, Dublin, Ireland), and required a prolonged respiratory wean and 28 days of hemofiltration. On discharge, his renal function returned to baseline, with a creatinine level of 90 mmol/L. Follow-up scanning at 6 months revealed no endoleak or increase in sac size.
CASE REPORT 2 A 60-year-old man underwent an endovascular repair of an infrarenal AAA using a Medtronic Talent stent graft (Santa Rosa, CA). An open repair of a left common femoral artery aneurysm was also performed. He
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Case reports 1127.e3
Fig. 2. (A) Intraoperative image illustrating the anastomosis of the splenic artery to the renal artery in an end-to-side manner during an open hepato-spleno-renal bypass. (B) Reconstructed computed tomography angiogram after bypass. underwent the procedure seemingly without any complications, but became anuric postoperatively, requiring renal replacement therapy at a regional dialysis unit. CT scanning demonstrated coverage of both renal arteries by the stent-graft main body fabric, and he was therefore referred to our institution, 5 weeks after EVAR, for an opinion on further management. Repeat CT scanning at this time demonstrated no loss in kidney size, with cortical enhancement, presumably from collateral supply. A decision was made to proceed with surgical revascularization in the hope of reestablishing adequate renal perfusion and reversing the need for renal support. Hepatorenal and splenorenal bypasses were performed through a bilateral subcostal incision. With a left medial visceral rotation, the splenic artery was dissected, ligated, and anastomosed to the left renal artery in an end-to-side manner (Fig. 2). The right renal artery was exposed after mobilization of the right colon and duodenum. A reversed long saphenous vein graft harvested from the left thigh was used as a conduit graft from the common hepatic artery to the right renal artery, again in an end-to-side manner. The patient started passing urine on day 5 postoperatively, he no longer required hemofiltration by day 8, and was subsequently discharged, with a creatinine level of 122 mmol/L. At 3-years follow-up after the procedure, his creatinine level remained within normal limits, and follow-up imaging revealed no endoleak or increase in sac size.
CASE REPORT 3 A 76-year-old man underwent an elective EVAR for an infrarenal AAA using a Medtronic Talent stent graft (Santa Rosa, CA). Although the initial operation was uneventful, early postoperative oliguria and progressively rising plasma creatinine levels prompted further imaging at 1 week postoperatively. CT scanning and renal angiography confirmed bilateral renal artery occlusion. In this case, the stent-graft main body fabric was seen below the renal artery origin bilaterally. However, due to significant preexisting bilateral renal artery stenoses, aortic stent placement led to occlusion.
He underwent hemofiltration in the intensive care unit, and showed subsequent enhancement of the kidneys bilaterally on CT scanning. The decision was made, 2 weeks after the initial EVAR, to perform hepatorenal and splenorenal bypasses. At 6-month followup, normal renal function was restored, and at 2 years, the creatinine levels remained within normal limits. Follow-up scanning at 6 months revealed no endoleak or increase in sac size.
CASE REPORT 4 An 89-year-old man underwent an elective EVAR for an infrarenal AAA using a Medtronic Endurant stent (Santa Rosa, CA). Preoperatively, he was found to have mild chronic renal impairment, with a creatinine level of 170 mmol/L, and he was therefore admitted for intravenous fluid rehydration and administration of N-acetylcysteine before the surgery. The procedure itself was complicated by a type 1a endoleak necessitating proximal extension. Completion angiography demonstrated some contrast filling of the renal arteries bilaterally, and he was discharged 2 days postoperatively. Three weeks postoperatively, he was readmitted with acute renal failure and a creatinine level of 300 mmol/L; ultrasonographic scanning showed thinning of the left renal cortex and heterogenous appearance of the right kidney. Subsequent CT scanning demonstrated complete coverage of the left renal artery by the fabric of the main aortic stent graft, and the origin of the right renal artery partially covered by the stent-graft fabric, with a significant underlying renal artery stenosis. The patient was transferred to our institution and underwent hemofiltration. Using local anesthesia and left brachial artery access via a 6-F sheath, angiography was performed, which confirmed the significant compromise of the right renal artery origin by the stent graft and occlusion of the left renal artery at the origin. Selective catheterization of the right renal artery through a long 7-F catheter as in case 1 was followed by successful deployment of a balloon-expandable stent. Excellent angiographic results were obtained, and no immediate complications were reported. At a 3-month follow-up, the patient’s renal function significantly improved, with
1127.e4 Case reports
a creatinine level of 190 mmol/L, and follow-up imaging revealed no endoleak or increase in sac size.
DISCUSSION Renal morbidity ranks third in the incidence of undesirable outcome after open4 and endovascular5 aneurysm repair, and remains a predictor of diminished long-term survival.6 Renal artery occlusion secondary to aortic stent-graft impingement is an uncommon, but important, cause of renal morbidity, especially as the accepted indications for EVAR increase. Current estimates suggest that approximately three-quarters of all patients with AAAs are amenable to EVAR using commercially available devices.7 Many centers are now routinely performing endovascular repairs for infrarenal aneurysms with short angulated necks and complex iliac anatomy, increasing the chances of renal artery interference. At present, there are few reports documenting renal salvage maneuvres after accidental renal artery occlusion during EVAR, and more importantly, there is no consensus regarding the optimum approach for subsequent revascularization after prolonged renal artery occlusion. With regard to renal salvage strategies used at the time of operation, various endovascular techniques have been reported. Ohrlander et al.3 describe their experience of placing renal artery chimney stents during EVAR for infrarenal abdominal aortic aneurysms (IRAAAs), both as a planned procedure (two patients) and as a rescue maneuver (four patients). Of these patients, one required chronic hemodialysis (ruptured AAA).3 Another method is the ‘‘encroachment’’ technique, which aims to restore renal perfusion by selectively catheterizing the renal artery through the aortic stent, with subsequent renal artery stenting. This maneuver aims to push the proximal margin of the ‘‘encroaching’’ aortic stent graft down toward the aneurysm.1 Clearly, conversion to open repair and other surgical techniques for renal bypass described later in the text have been used immediately after stent-graft misplacement, but unsurprisingly, these cases are rarely reported. Unintentional unrecognized renal artery occlusion after EVAR and the options for treatment are not well documented. Hedayati et al.8 describe two cases of renal salvage in patients who presented 1 week after EVAR. The first patient presented with severe hypertension (210/140 mm Hg), and the second patient presented with oliguria and confusion secondary to uremia. Angiography confirmed unilateral (right) renal artery occlusion in both
Annals of Vascular Surgery
patients. Both cases were successfully managed using selective renal artery catheterization and stenting via a femoral approach, with return of normal renal function and blood pressure at 1 month and 6 months, respectively.8 Hamish et al. have reported a case of successful delayed renal revascularization using hepatorenal and splenorenal bypasses after accidental bilateral renal artery coverage during endovascular repair of an infrarenal AAA.9 Management options for restoration of renal artery blood flow after unintentional coverage are varied, including hepatorenal and splenorenal bypass, antegrade/retrograde surgical revascularization, stent-graft removal, chimney stent placement, and experimental techniques such as in situ fenestration. Hepatorenal and Splenorenal Bypass Patients with complete bilateral renal artery occlusion after EVAR may undergo hepatorenal and splenorenal bypass as described in the cases earlier in the text. The authors consider that in cases where the aortic stent graft has covered the renal arteries for a number of weeks, this procedure may be a safer option to avoid the tearing of the aortic wall during attempts to lift away the fabric of the stent graft during endovascular approaches. Antegrade/Retrograde Surgical Revascularization Antegrade renal revascularization is possible from the suprarenal or thoracic aorta and is occasionally the optimal approach, especially when the iliac vessels are not suitable for a retrograde approach. Bypass grafts from the iliac artery to the renal arteries may also be used to reestablish flow, in a technique similar to that used in visceral hybrid surgical/endovascular thoracoabdominal aneurysm repair. Our experience from hybrid surgery would suggest that this technique is acceptable, with good graft patency rates. However, after EVAR, most surgeons will cover the entire CIA to achieve maximum distal fixation, and so retrograde grafts must be taken from the external iliac arteries, which is a less suitable inflow vessel. Therefore, we suggest that this technique be reserved for cases where the splenic and hepatic vessels are not suitable, such as in the presence of celiac artery occlusion. Stent-Graft Removal Removal of the EVAR device and open surgical repair may be used to reestablish renal artery flow.
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Fig. 3. Early treatment strategies most often used for the management of unintentional unrecognized renal artery coverage after endovascular aortic aneurysm repair.
However, as those who have performed this procedure are aware, it is not an easy undertaking, necessitating suprarenal or supraceliac aortic cross clamping, resulting in further renal insult and requiring a medial visceral rotation in patients whose stent grafts have been deployed high. Relevant to this group of patients is the fact that after a few weeks, the stent-graft support struts (and suprarenal fixation structure) becomes deeply adherent to the aortic wall and may risk further renal artery damage with removal. Chimney Stent Placement This technique is described fully in case 1 of our series. It is a useful technique as a minimally invasive method to reestablish renal perfusion. It may be particularly useful where there is prompt recognition of renal artery coverage and the main body of the stent graft can be lifted from the aorta with ease, or where there is a ‘‘leak’’ of contrast media between the aorta and the main body of the stent graft into the renal artery, which can then be accessed with a wire. Experimental Techniques: In Situ Fenestration Antegrade in situ fenestration of abdominal aortic stents has been described in canine models10 and
also in porcine models using robotic assistance.11,12 Through the aortic graft, a fenestration can be fashioned using one of a variety of techniques, and covered stents can be placed into the target vessels. However, this technique is technically challenging and is, at present, in an experimental stage, with no reports in the literature of human cases. There are a number of reasons why renal artery coverage may be missed on completion angiography. In our series, misinterpretation of the initial completion angiogram is the most likely explanation is cases 1 and 2. Stent migrationdperhaps after removal of stiff wiresdis another possibility. When deciding whether to attempt renal revascularization and choosing the optimal technique, the clinician should take a balanced approach. The time elapsed between renal artery coverage and recognition is crucial. Clearly, in those cases where recognition occurs soon after the event, renal reperfusion should be attempted. For those who present later, renal size and cortical enhancement should be assessed, as there is no merit in attempting to revascularize completely infarcted small kidneys. There is no entirely satisfactory way of determining whether renal function will return to baseline after revascularization. However, an unsalvageable kidney that presents late will not have any degree of renal cortical enhancement and would be
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Fig. 4. Late treatment strategies most often used for the management of unintentional, unrecognized renal artery coverage after endovascular aortic aneurysm repair.
significantly smaller than is considered normal on CT evaluation. Additionally, the patency of the renal vessels must be carefully evaluated. Partially occluded renal arteries and those that are filling from the origin despite stent-graft main body coverage may be amenable to endovascular intervention. Conversely, open surgery is often considered first in those who present late with complete renal artery occlusion, as the stent graft is likely to be deeply adherent to the aorta and may prove difficult to lift away from aortic wall using endovascular techniques. Our policy is to aim to revascularize both kidneys; however, the final decision to revascularize one or both kidneys is dictated by the clinical scenario. In unstable patients who present as an emergency (as in case 1), it may be safer and faster to revascularize one kidney, rather than attempt to reestablish flow to both kidneys with a more lengthy procedure and risk further deterioration in an already unstable patient. In patients who are clinically stable and
who present several weeks later (as in case 2), one can consider revascularizing both kidneys using an open surgical technique. With regard to the type of stent used for the chimney technique, we advocate the use of covered stents if there is a concern that the procedure will cause a type 1a endoleak, or if the landing zone of the aortic stent is not considered to be sufficient to create good seal. If the proximal aortic stent seal is deemed to be sufficient, it is acceptable to use a bare stent. Figures 3 and 4 illustrate our suggested treatment algorithms for unintentional unrecognized renal artery coverage after EVAR, taking these factors into account.
CONCLUSION Renal artery occlusion after EVAR is rare, but if unrecognized and untreated, it may lead to permanent renal failure, mandating renal replacement
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therapy. Treatment strategies are varied. Both open and endovascular techniques may be used as procedures to treat this conditiondthe choice of procedure largely determined by accessibility of the renal orifice.
Case reports 1127.e7
6.
7.
REFERENCES 8. 1. Hiramoto JS, Chang CK, Reilly LM, et al. Outcome of renal stenting for renal artery coverage during endovascular aortic aneurysm repair. J Vasc Surg 2009;49:1100e6. 2. Vourliotakis G, Blanch M, Zeebregts CJ, et al. Intraoperative salvage of a renal artery occlusion during fenestrated stent grafting. J Vasc Surg 2009;50:1481e3. 3. Ohrlander T, Sonesson B, Ivancev K, et al. The chimney graft: a technique for preserving or rescuing aortic branch vessels in stent-graft sealing zones. J Endovasc Ther 2008;15:427e32. 4. Johnston K. Multicenter prospective study of nonruptured abdominal aortic aneurysms. II: variable in predicting morbidity and mortality. J Vasc Surg 1989;9:437e47. 5. Greenberg RK, Chuter TAM, Lawrence-Brown M, et al. Analysis of renal function after aneurysm repair with a device using suprarenal fixation (Zenith AAA Endovascu-
9.
10.
11.
12.
lar Graft) in contrast to open surgical repair. J Vasc Surg 2004;39:1219e28. Hertzer NR, Mascha EJ, Karaf MT, et al. Open infrarenal abdominal aortic aneurysm repair: the Cleveland clinic experience from 1989 to 1998. J Vasc Surg 2002;35: 1145e54. Keefer A, Hislop S, Singh MJ, et al. The influence of aneurysm size on anatomic suitability for endovascular repair. J Vasc Surg 2010;52:873e7. Hedayati N, Lin PH, Lumsden AB, Zhou W. Prolonged renal artery occlusion after endovascular aneurysm repair: endovascular rescue and renal function salvage. J Vasc Surg 2008;47:446e9. Hamish M, Geroulakos G, Hughes DA, et al. Delayed hepatospleno-renal bypass for renal salvage following malposition of an infrarenal aortic stent graft. J Endovasc Ther 2010;17:326e31. Tse LW, Bui BT, Leroughe S, et al. In vivo antegrade fenestration of abdominal aortic stent-grafts. J Endovasc Ther 2007;14:158e67. Riga CV, Bicknell CD, Wallace D, et al. Robot-assisted antegrade in-situ fenestrated stent grafting. Cardiovasc Intervent Radiol 2009;32:522e4. Riga CV, Cheshire NJW, Hamady MS, Bicknell CD. The role of robotic endovascular cathethers in fenestrated stent grafting. J Vasc Surg 2009;51:810e20.
Background: Unintentional renal artery occlusion after endovascular aortic aneurysm repair (EVAR) is an uncommon phenomenon. The sequelae from this specific complication are severe; consequently, the topic of renal artery coverage is a pertinent issue. We present a case series of patients undergoing EVAR with unintentional renal artery coverage, review the treatment options available, and suggest a treatment algorithm for this scenario based on the evidence. Methods and Results: We report four patients who were found to have renal artery occlusion after EVAR detected up to 5 weeks postoperatively. Renal revascularization was achieved using endovascular renal artery stenting in two patients, and open hepato-spleno-renal bypass in the remaining two cases. Treatment strategies used led to symptom resolution and recovery of renal function in all cases. Conclusions: Both open and endovascular techniques may be used as procedures to treat this conditiondthe choice of procedure is primarily determined by accessibility of the renal orifice.
Unintentional renal artery occlusion after endovascular aortic aneurysm repair (EVAR) is an uncommon phenomenon. However, as operators performing endovascular intervention have become more ambitious, shorter and more angulated aortic neck configurations are being tackled with standard stent grafts, increasing the risk of renal artery coverage/occlusion. The sequelae from this specific complication are severe; consequently, the topic of renal artery coverage is a pertinent issue.
1 Imperial Vascular Unit, St Mary’s Campus, Imperial College Healthcare NHS Trust, London, UK. 2 Department of Surgery and Cancer, Imperial College London, London, UK. 3 Department of Interventional Radiology, St Mary’s Campus, Imperial College Healthcare NHS Trust, London, UK. Correspondence to: Colin D. Bicknell, MD, FRCS, Vascular Secretaries Office, Waller Cardiac Building, St. Mary’s Hospital, Praed Street, London W2 1NY, UK; E-mail: [email protected]
Ann Vasc Surg 2012; 26: 1127.e1e1127.e7 DOI: 10.1016/j.avsg.2012.02.018 Ó Annals of Vascular Surgery Inc.
Techniques for renal artery salvage as an emergency maneuver during EVAR are fairly well described.1e3 However, when renal artery occlusion is unrecognized, presenting hours, days, or weeks after EVAR, management strategies are unclear. The aim of this article is to present a case series of patients undergoing EVAR with unintentional renal artery coverage, review the treatment options available, and suggest a treatment algorithm for this scenario based on the evidence. All patients in our series were initially treated at their local hospital and later transferred to our tertiary referral unit.
CASE REPORT 1 A 78-year-old man presented to his local hospital with sudden-onset loin pain. Urgent computed tomography (CT) angiography demonstrated a ruptured infrarenal abdominal aortic aneurysm (AAA) with a significantly angulated proximal neck. He underwent emergency endovascular aneurysm repair receiving local anesthesia. An aortouniiliac Medtronic Endurant stent (Santa Rosa, 1127.e1
1127.e2 Case reports
Annals of Vascular Surgery
Fig. 1. (A, B) Angiograms acquired before chimney stent placement demonstrating renal vessel filling via a small channel between the main body of the stent graft and the aorta. (C) Selective cannulation of the left renal
artery. (D) Postestent insertion completion angiogram confirming patency of the left renal artery and its branches. (E) Subsequent reconstructed computed tomography angiogram.
CA) was deployed via the right groin, followed by limb extension to the right common iliac artery (CIA) and Amplatzer 22-mm device placement to occlude the proximal left CIA. The postdeployment angiogram demonstrated a type 1a endoleak, which was managed with a proximal aortic extension cuff. Completion angiogram confirmed exclusion of the aneurysm, no endoleak, and perfusion of both renal arteries. A right-to-left femorale femoral crossover graft was then constructed using an 8mm Dacron graft. He was subsequently transferred to our institution, necessitated by intensive care unit (ICU) bed unavailability at his local hospital. Although he appeared well initially postoperatively, worsening oliguria, significant respiratory compromise, and rising intra-abdominal compartment pressures mandated urgent laparostomy formation with Bogota bag closure at 18 hours after EVAR. After this, he became anuric. Subsequent CT scanning demonstrated coverage of both renal arteries, with some left renal vessel filling via a small channel between the main body of the stent graft and the aorta. He underwent urgent angiography and chimney stent placement. Access was obtained from the left brachial artery via a 6-F sheath. A 0.035-inch Terumo wire (Terumo Europe, Leuven, Belgium) was passed between the main body of the stent graft and the aortic wall into the left renal artery and exchanged for a 0.035-inch Amplatz
wire (Cook Medical, Bloomington, IN). A 7-mm balloon was inflated between the aorta and the main of the body device to lift the fabric of the stent away from the aortic wall. Three 6 22-mm Advanta covered stents (Atrium, Hudson, OH) were subsequently deployed to bridge the gap between the aorta and the left renal artery. Postoperative angiograms demonstrated good stent position, perfusion of the left renal artery, and no evidence of an endoleak (Fig. 1). There was no attempt made to salvage the right renal artery because this kidney was most likely ischemic, and the patient was too unstable for bilateral prolonged attempts at renal salvage. During his 62-day ITU stay, he underwent closure of laparostomy defect using a Permacol porcine collagen mesh (Covidien PLC, Dublin, Ireland), and required a prolonged respiratory wean and 28 days of hemofiltration. On discharge, his renal function returned to baseline, with a creatinine level of 90 mmol/L. Follow-up scanning at 6 months revealed no endoleak or increase in sac size.
CASE REPORT 2 A 60-year-old man underwent an endovascular repair of an infrarenal AAA using a Medtronic Talent stent graft (Santa Rosa, CA). An open repair of a left common femoral artery aneurysm was also performed. He
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Case reports 1127.e3
Fig. 2. (A) Intraoperative image illustrating the anastomosis of the splenic artery to the renal artery in an end-to-side manner during an open hepato-spleno-renal bypass. (B) Reconstructed computed tomography angiogram after bypass. underwent the procedure seemingly without any complications, but became anuric postoperatively, requiring renal replacement therapy at a regional dialysis unit. CT scanning demonstrated coverage of both renal arteries by the stent-graft main body fabric, and he was therefore referred to our institution, 5 weeks after EVAR, for an opinion on further management. Repeat CT scanning at this time demonstrated no loss in kidney size, with cortical enhancement, presumably from collateral supply. A decision was made to proceed with surgical revascularization in the hope of reestablishing adequate renal perfusion and reversing the need for renal support. Hepatorenal and splenorenal bypasses were performed through a bilateral subcostal incision. With a left medial visceral rotation, the splenic artery was dissected, ligated, and anastomosed to the left renal artery in an end-to-side manner (Fig. 2). The right renal artery was exposed after mobilization of the right colon and duodenum. A reversed long saphenous vein graft harvested from the left thigh was used as a conduit graft from the common hepatic artery to the right renal artery, again in an end-to-side manner. The patient started passing urine on day 5 postoperatively, he no longer required hemofiltration by day 8, and was subsequently discharged, with a creatinine level of 122 mmol/L. At 3-years follow-up after the procedure, his creatinine level remained within normal limits, and follow-up imaging revealed no endoleak or increase in sac size.
CASE REPORT 3 A 76-year-old man underwent an elective EVAR for an infrarenal AAA using a Medtronic Talent stent graft (Santa Rosa, CA). Although the initial operation was uneventful, early postoperative oliguria and progressively rising plasma creatinine levels prompted further imaging at 1 week postoperatively. CT scanning and renal angiography confirmed bilateral renal artery occlusion. In this case, the stent-graft main body fabric was seen below the renal artery origin bilaterally. However, due to significant preexisting bilateral renal artery stenoses, aortic stent placement led to occlusion.
He underwent hemofiltration in the intensive care unit, and showed subsequent enhancement of the kidneys bilaterally on CT scanning. The decision was made, 2 weeks after the initial EVAR, to perform hepatorenal and splenorenal bypasses. At 6-month followup, normal renal function was restored, and at 2 years, the creatinine levels remained within normal limits. Follow-up scanning at 6 months revealed no endoleak or increase in sac size.
CASE REPORT 4 An 89-year-old man underwent an elective EVAR for an infrarenal AAA using a Medtronic Endurant stent (Santa Rosa, CA). Preoperatively, he was found to have mild chronic renal impairment, with a creatinine level of 170 mmol/L, and he was therefore admitted for intravenous fluid rehydration and administration of N-acetylcysteine before the surgery. The procedure itself was complicated by a type 1a endoleak necessitating proximal extension. Completion angiography demonstrated some contrast filling of the renal arteries bilaterally, and he was discharged 2 days postoperatively. Three weeks postoperatively, he was readmitted with acute renal failure and a creatinine level of 300 mmol/L; ultrasonographic scanning showed thinning of the left renal cortex and heterogenous appearance of the right kidney. Subsequent CT scanning demonstrated complete coverage of the left renal artery by the fabric of the main aortic stent graft, and the origin of the right renal artery partially covered by the stent-graft fabric, with a significant underlying renal artery stenosis. The patient was transferred to our institution and underwent hemofiltration. Using local anesthesia and left brachial artery access via a 6-F sheath, angiography was performed, which confirmed the significant compromise of the right renal artery origin by the stent graft and occlusion of the left renal artery at the origin. Selective catheterization of the right renal artery through a long 7-F catheter as in case 1 was followed by successful deployment of a balloon-expandable stent. Excellent angiographic results were obtained, and no immediate complications were reported. At a 3-month follow-up, the patient’s renal function significantly improved, with
1127.e4 Case reports
a creatinine level of 190 mmol/L, and follow-up imaging revealed no endoleak or increase in sac size.
DISCUSSION Renal morbidity ranks third in the incidence of undesirable outcome after open4 and endovascular5 aneurysm repair, and remains a predictor of diminished long-term survival.6 Renal artery occlusion secondary to aortic stent-graft impingement is an uncommon, but important, cause of renal morbidity, especially as the accepted indications for EVAR increase. Current estimates suggest that approximately three-quarters of all patients with AAAs are amenable to EVAR using commercially available devices.7 Many centers are now routinely performing endovascular repairs for infrarenal aneurysms with short angulated necks and complex iliac anatomy, increasing the chances of renal artery interference. At present, there are few reports documenting renal salvage maneuvres after accidental renal artery occlusion during EVAR, and more importantly, there is no consensus regarding the optimum approach for subsequent revascularization after prolonged renal artery occlusion. With regard to renal salvage strategies used at the time of operation, various endovascular techniques have been reported. Ohrlander et al.3 describe their experience of placing renal artery chimney stents during EVAR for infrarenal abdominal aortic aneurysms (IRAAAs), both as a planned procedure (two patients) and as a rescue maneuver (four patients). Of these patients, one required chronic hemodialysis (ruptured AAA).3 Another method is the ‘‘encroachment’’ technique, which aims to restore renal perfusion by selectively catheterizing the renal artery through the aortic stent, with subsequent renal artery stenting. This maneuver aims to push the proximal margin of the ‘‘encroaching’’ aortic stent graft down toward the aneurysm.1 Clearly, conversion to open repair and other surgical techniques for renal bypass described later in the text have been used immediately after stent-graft misplacement, but unsurprisingly, these cases are rarely reported. Unintentional unrecognized renal artery occlusion after EVAR and the options for treatment are not well documented. Hedayati et al.8 describe two cases of renal salvage in patients who presented 1 week after EVAR. The first patient presented with severe hypertension (210/140 mm Hg), and the second patient presented with oliguria and confusion secondary to uremia. Angiography confirmed unilateral (right) renal artery occlusion in both
Annals of Vascular Surgery
patients. Both cases were successfully managed using selective renal artery catheterization and stenting via a femoral approach, with return of normal renal function and blood pressure at 1 month and 6 months, respectively.8 Hamish et al. have reported a case of successful delayed renal revascularization using hepatorenal and splenorenal bypasses after accidental bilateral renal artery coverage during endovascular repair of an infrarenal AAA.9 Management options for restoration of renal artery blood flow after unintentional coverage are varied, including hepatorenal and splenorenal bypass, antegrade/retrograde surgical revascularization, stent-graft removal, chimney stent placement, and experimental techniques such as in situ fenestration. Hepatorenal and Splenorenal Bypass Patients with complete bilateral renal artery occlusion after EVAR may undergo hepatorenal and splenorenal bypass as described in the cases earlier in the text. The authors consider that in cases where the aortic stent graft has covered the renal arteries for a number of weeks, this procedure may be a safer option to avoid the tearing of the aortic wall during attempts to lift away the fabric of the stent graft during endovascular approaches. Antegrade/Retrograde Surgical Revascularization Antegrade renal revascularization is possible from the suprarenal or thoracic aorta and is occasionally the optimal approach, especially when the iliac vessels are not suitable for a retrograde approach. Bypass grafts from the iliac artery to the renal arteries may also be used to reestablish flow, in a technique similar to that used in visceral hybrid surgical/endovascular thoracoabdominal aneurysm repair. Our experience from hybrid surgery would suggest that this technique is acceptable, with good graft patency rates. However, after EVAR, most surgeons will cover the entire CIA to achieve maximum distal fixation, and so retrograde grafts must be taken from the external iliac arteries, which is a less suitable inflow vessel. Therefore, we suggest that this technique be reserved for cases where the splenic and hepatic vessels are not suitable, such as in the presence of celiac artery occlusion. Stent-Graft Removal Removal of the EVAR device and open surgical repair may be used to reestablish renal artery flow.
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Fig. 3. Early treatment strategies most often used for the management of unintentional unrecognized renal artery coverage after endovascular aortic aneurysm repair.
However, as those who have performed this procedure are aware, it is not an easy undertaking, necessitating suprarenal or supraceliac aortic cross clamping, resulting in further renal insult and requiring a medial visceral rotation in patients whose stent grafts have been deployed high. Relevant to this group of patients is the fact that after a few weeks, the stent-graft support struts (and suprarenal fixation structure) becomes deeply adherent to the aortic wall and may risk further renal artery damage with removal. Chimney Stent Placement This technique is described fully in case 1 of our series. It is a useful technique as a minimally invasive method to reestablish renal perfusion. It may be particularly useful where there is prompt recognition of renal artery coverage and the main body of the stent graft can be lifted from the aorta with ease, or where there is a ‘‘leak’’ of contrast media between the aorta and the main body of the stent graft into the renal artery, which can then be accessed with a wire. Experimental Techniques: In Situ Fenestration Antegrade in situ fenestration of abdominal aortic stents has been described in canine models10 and
also in porcine models using robotic assistance.11,12 Through the aortic graft, a fenestration can be fashioned using one of a variety of techniques, and covered stents can be placed into the target vessels. However, this technique is technically challenging and is, at present, in an experimental stage, with no reports in the literature of human cases. There are a number of reasons why renal artery coverage may be missed on completion angiography. In our series, misinterpretation of the initial completion angiogram is the most likely explanation is cases 1 and 2. Stent migrationdperhaps after removal of stiff wiresdis another possibility. When deciding whether to attempt renal revascularization and choosing the optimal technique, the clinician should take a balanced approach. The time elapsed between renal artery coverage and recognition is crucial. Clearly, in those cases where recognition occurs soon after the event, renal reperfusion should be attempted. For those who present later, renal size and cortical enhancement should be assessed, as there is no merit in attempting to revascularize completely infarcted small kidneys. There is no entirely satisfactory way of determining whether renal function will return to baseline after revascularization. However, an unsalvageable kidney that presents late will not have any degree of renal cortical enhancement and would be
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Fig. 4. Late treatment strategies most often used for the management of unintentional, unrecognized renal artery coverage after endovascular aortic aneurysm repair.
significantly smaller than is considered normal on CT evaluation. Additionally, the patency of the renal vessels must be carefully evaluated. Partially occluded renal arteries and those that are filling from the origin despite stent-graft main body coverage may be amenable to endovascular intervention. Conversely, open surgery is often considered first in those who present late with complete renal artery occlusion, as the stent graft is likely to be deeply adherent to the aorta and may prove difficult to lift away from aortic wall using endovascular techniques. Our policy is to aim to revascularize both kidneys; however, the final decision to revascularize one or both kidneys is dictated by the clinical scenario. In unstable patients who present as an emergency (as in case 1), it may be safer and faster to revascularize one kidney, rather than attempt to reestablish flow to both kidneys with a more lengthy procedure and risk further deterioration in an already unstable patient. In patients who are clinically stable and
who present several weeks later (as in case 2), one can consider revascularizing both kidneys using an open surgical technique. With regard to the type of stent used for the chimney technique, we advocate the use of covered stents if there is a concern that the procedure will cause a type 1a endoleak, or if the landing zone of the aortic stent is not considered to be sufficient to create good seal. If the proximal aortic stent seal is deemed to be sufficient, it is acceptable to use a bare stent. Figures 3 and 4 illustrate our suggested treatment algorithms for unintentional unrecognized renal artery coverage after EVAR, taking these factors into account.
CONCLUSION Renal artery occlusion after EVAR is rare, but if unrecognized and untreated, it may lead to permanent renal failure, mandating renal replacement
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therapy. Treatment strategies are varied. Both open and endovascular techniques may be used as procedures to treat this conditiondthe choice of procedure largely determined by accessibility of the renal orifice.
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REFERENCES 8. 1. Hiramoto JS, Chang CK, Reilly LM, et al. Outcome of renal stenting for renal artery coverage during endovascular aortic aneurysm repair. J Vasc Surg 2009;49:1100e6. 2. Vourliotakis G, Blanch M, Zeebregts CJ, et al. Intraoperative salvage of a renal artery occlusion during fenestrated stent grafting. J Vasc Surg 2009;50:1481e3. 3. Ohrlander T, Sonesson B, Ivancev K, et al. The chimney graft: a technique for preserving or rescuing aortic branch vessels in stent-graft sealing zones. J Endovasc Ther 2008;15:427e32. 4. Johnston K. Multicenter prospective study of nonruptured abdominal aortic aneurysms. II: variable in predicting morbidity and mortality. J Vasc Surg 1989;9:437e47. 5. Greenberg RK, Chuter TAM, Lawrence-Brown M, et al. Analysis of renal function after aneurysm repair with a device using suprarenal fixation (Zenith AAA Endovascu-
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lar Graft) in contrast to open surgical repair. J Vasc Surg 2004;39:1219e28. Hertzer NR, Mascha EJ, Karaf MT, et al. Open infrarenal abdominal aortic aneurysm repair: the Cleveland clinic experience from 1989 to 1998. J Vasc Surg 2002;35: 1145e54. Keefer A, Hislop S, Singh MJ, et al. The influence of aneurysm size on anatomic suitability for endovascular repair. J Vasc Surg 2010;52:873e7. Hedayati N, Lin PH, Lumsden AB, Zhou W. Prolonged renal artery occlusion after endovascular aneurysm repair: endovascular rescue and renal function salvage. J Vasc Surg 2008;47:446e9. Hamish M, Geroulakos G, Hughes DA, et al. Delayed hepatospleno-renal bypass for renal salvage following malposition of an infrarenal aortic stent graft. J Endovasc Ther 2010;17:326e31. Tse LW, Bui BT, Leroughe S, et al. In vivo antegrade fenestration of abdominal aortic stent-grafts. J Endovasc Ther 2007;14:158e67. Riga CV, Bicknell CD, Wallace D, et al. Robot-assisted antegrade in-situ fenestrated stent grafting. Cardiovasc Intervent Radiol 2009;32:522e4. Riga CV, Cheshire NJW, Hamady MS, Bicknell CD. The role of robotic endovascular cathethers in fenestrated stent grafting. J Vasc Surg 2009;51:810e20.