Embolization as cause of bowel ischemia after endovascular abdominal aortic aneurysm repair

Abstract

We investigated the incidence, cause, and outcome of large bowel and small bowel ischemia after endovascular abdominal aortic aneurysm (AAA) repair. Medical records for all patients undergoing endovascular AAA repair from December 1999 to December 2003 were reviewed. The incidence, cause, and outcome of clinically detected postoperative bowel ischemia were analyzed. Seven hundred two endovascular AAA repairs were performed. In 10 patients (1.4%) acute bowel ischemia developed. Six of these patients sustained concurrent small bowel necrosis, and the remaining 4 had isolated colon ischemia. Seven patients underwent exploratory laparotomy. In 6 of these bowel resection was performed, and in 1 patient the ischemic bowel was unsalvageable. Of the 6 patients with small and large bowel ischemia, 4 had segmental or patchy necrosis, which was separated by normal-appearing intestine, and 1 had extensive ischemia that involved most of the small bowel and the entire colon, with pathologic evidence of microembolization. Three patients had preoperative occlusion of the inferior mesenteric artery. One had unilateral and 1 had bilateral hypogastric artery interruption. Five of the 6 patients with small bowel ischemia had thrombus or atheroma in the proximal aneurysmal necks. All patients with isolated colon ischemia survived. All 6 patients with concurrent small bowel ischemia died. The total incidence of clinically evident bowel ischemia after endovascular AAA repair is similar to that after open surgery. However, small bowel ischemia occurs more commonly in patients with endovascular repair, and is associated with extremely high mortality. The direct pathologic evidence and the patterns of segmental, skipped, or patchy ischemia in most patients imply that microembolization has an important role.