Incidence and Risk Factors of Ischemic Colitis after AAA Repair in Our Cohort of Patients from 2005 through 2009

Summary

Introduction:
Using retrospective analysis, we sought to investigate the incidence, risk factors and therapeutic outcomes of ischemic colitis in patients after surgical and endovascular repair of abdominal aortic aneurysms (AAA).

Material and methods:
The complete inpatient and outpatient medical records of all patients undergoing surgical or endovascular AAA repair in our Department from January 2005 to December 2009 were retrospectively reviewed. We selected all patients who had developed an acute or chronic form of postoperative large or small bowel ischemia . We carried out data analysis and focused on determining the incidence and risk factors of this complication and the outcomes of its treatment.

Results:
Two hundred and seven AAA repairs were performed in the 2^nd Department of Surgery of St. Anne’s University Hospital in Brno and the Faculty of Medicine of Masaryk University in Brno during the studied period. This number includes endovascular AAA repairs (13 patients; 6.3%) as well as one robot-assisted operation, and also the whole clinical spectrum of AAA manifestations, from non-symptomatic forms to ruptured aneurysm forms. The rest of the patients underwent open operation. Bowel ischemia developed in a total of 11 patients (5.3 %), who all underwent open AAA repair. Six of these patients presented with non-ruptured AAA and the remaining 5 with ruptured AAA. In 3 patients, bowel ischemia was diagnosed with a delay of several months from the original revascularization operation in the clinical form of postischemic stricture of the large bowel (2 patients) or postischemic colitis (1 patient). 8 patients were diagnosed with acute ischemic colitis affecting an isolated segment of the small bowel in one patient, extended segments of the large bowel (descending colon + sigmoid colon + rectum) in 2 patients, and typically the descending and sigmoid colon in 5 patients. None of the three patients with late manifestation of ischemic colitis died. Of the 8 patients with acute presentation, resection of the ischemic bowel +/- the rectum was performed in 6 patients. 3 of them died and 3 survived the operation and have been followed up in our outpatient department. 2 patients with acute manifestation did not undergo bowel resection. Both of them died. The overall mortality of all patients with ischemic colitis was 45.5% (5 patients out of 11 died) in our study. When considering only patients suffering from the acute form of ischemic colitis, the mortality rate in our studied cohort amounts to 62.5% (5 patients out of 8 died).

Conclusion:
Bowel ischemia after AAA repair remains to be a serious complication. Besides the acute form of ischemic colitis, its possible late clinical manifestation in the form of postischemic stricture of the large bowel or postischemic large bowel colitis must also be kept in mind when following up patients. The analysis of our patient’s data shows that conditions requiring the use of vasopressors and an increased need of transfusions (more than 7 units of packed red blood cells) intraoperatively represent important predictors of colon ischemia after AAA repair.

Key words:
ischemic colitis – bowel ischemia – postischemic stricture and colitis – abdominal aortic aneurysm repair