Overt Colonic Ischemia after Endovascular Repair of Thoracoabdominal Aortic Aneurysms with Visceral Revascularization

Objective: Endovascular repair of thoracoabdominal aortic aneurysms in high-risk patients without suitable anatomy requires visceral revascularization to lengthen the proximal and/or distal neck. The purpose of this study was to identify the frequency, severity and mechanisms of overt colonic ischemia after endovascular aneurysm repair(EVAR) of thoracoabdominal aneurysms with visceral revascularization.
Methods: Over a 12-month period, 28 patients underwent EVAR with visceral revascularization. In 27 patients(96%), both EVAR and visceral revascularization were completed. One patient underwent visceral relocation but not EVAR due to technical inability to deliver the endograft. Postoperative colonic ischemia was documented by colonoscopy or operative findings.
Results: In 4 patients(14%), over colonic ischemia developed 2.0±1.2 days postoperatively. Three of these 4 patients had undergone previous open abdominal aortic aneurysm(AAA) repair. Of the remaining 24 patients without overt colonic ischemia, 3 had undergone previous open AAA repair. Once the diagnosis was confirmed at colonoscopy, 3 patients required colonic resection due to transmural ischemia. Colonic resection was performed 3±4.2 days after visceral revascularization. The three patients that underwent colonic resection died postoperatively from sepsis and multiple system organ failure related to their colonic ischemia. Pathologic findings revealed transmural necrosis without microembolization in the colonic vasculature. One patient with mucosal ischemia recovered completely with nonoperative management. Prior open AAA repair was associated with a 20-fold increased risk of overt colonic ischemia after EVAR with visceral revascularization (odds ratio, 20; 95% confidence interval,1.6-273; P=.02).
Conclusions: Over colonic ischemia after EVAR with visceral revascularization is associated with significant mortality despite operative management. Inadequate mesenteric collateral circulation related to previous open AAA repair appears to be the major cause of colonic ischemia, whereas embolization may not occur.
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