Flexible sigmoidoscopy - A reliable determinant of colonic ischemia following ruptured abdominal aortic aneurysm

Background: The development of colonic ischemia following repair of ruptured abdominal aortic aneurysm (AAA) is associated with significant morbidity and timely diagnosis is essential. The purpose of this study was to determine the efficacy of endoscopy in the diagnosis of colonic ischemia and in prediction of need for resection. Methods: Patients who underwent postoperative lower endoscopy after ruptured AAA from 1986 to 1995 were reviewed for endoscopic findings, clinical course, and patient outcome. Results: A total of 80 patients had ruptured AAA during the study period, of which 56 survived for longer than 24 h postoperatively, Flexible lower endoscopy was done in 18 patients (32%) on an average of 4.4 days following AAA repair (range 1-16). Indications for initial endoscopy included early or bloody stools in 12 (67%), hemodynamic instability or sepsis in eight (44%), and acidosis in four (22%), The extent of the examination was sigmoid or descending colon in 13, cecum in four, and transverse colon in one, Endoscopic findings were normal in four patients. Five examinations showed only areas of hemorrhagic mucosa. Absence of full-thickness ischemia was confirmed by clinical course or autopsy in these nine patients, Two examinations demonstrated full-thickness necrosis which was confirmed at subsequent laparotomy. In six examinations, ischemia was noted but judged to be limited to mucosa only. Absence of full-thickness disease was demonstrated by laparotomy in three and subsequent course in three. Eight patients (57%) with initial abnormal examinations underwent repeat endoscopy showing improved interval appearance in seven cases and progression to full-thickness ischemia in one patient. Conclusions: Flexible sigmoidoscopy reliably predicts full-thickness colonic ischemia following repair of ruptured aortic aneurysms. Patients with non-confluent ischemia limited to the mucosa can be safely followed by serial endoscopic examinations.