Ischaemic colitis following aortoiliac surgery

Ischaemic colitis following aortoiliac surgery is a feared complication. Its frequency varies from 7% after repair of ruptured abdominal aortic aneurysm (AAA) to 0.6% after bypass for aortoiliac occlusive disease (AOD). In order to analyse predisposing factors and outcome of ischaemic colitis, the authors reviewed their clinical experience from 1988 to 1998. It concerns 28 cases (16 ruptured AAA, 7 elective AAA, 5 OAD) of clinically evident colonic ischaemia. This means an incidence of 7% after repair of ruptured AAA, 0.6% after elective AAA repair, and 0.8% after bypass for AOD. Transmural necrosis (grade 3) was observed in 21 patients, grade 2 ischaemia in 5 patients, and grade 1 ischaemia in 2 patients. Fifteen patients with grade 3 ischaemia underwent colectomy (Hartmann's procedure) with a mortality rate of 66%. All non operated grade 3 patients died. Overall, 16 of the 28 patients died at hospital (57% mortality rate). None of the patients with mild (grade 2 or 1) colonic ischaemia died. Profound hypovolaemic shock and inflammatory AAA were the only significant predisposing factors leading to colonic ischaemia. Associated colon revascularization could not avoid the evolution to colon necrosis in four patients. Reimplantation of a patent inferior mesenteric artery or an internal iliac artery was performed in only 4.8% of all aortoiliac reconstructions, and did not influence the development of ischaemic colitis. The authors conclude that a more liberal use of postoperative sigmoidoscopy could allow detecting colonic ischaemia at an earlier stage and reduce ensuing mortality. A reinforced effort to restore or preserve colonic vascularization could lower the incidence of colonic ischaemia following aortoiliac surgery.