Ischaemic disease of the colon and rectum after surgery for abdominal aortic aneurysm: a prospective study of the incidence and risk factors.

In a prospective study of 100 patients operated on for an infrarenal localised aortic aneurysm, routine postoperative colonoscopy revealed ischaemic colonic disease, defined as ulceration or necrosis of different degrees in three of 66 patients (4.5%) operated on electively or semi-acute, and in six of 34 patients (17.6%) operated on for a rupture of their aneurysm. Colonoscopic findings were interpreted as transmural gangrene in three patients, extensive superficial necrosis in one, and ulceration in five. Exploratory laparotomy, however, led to a definite diagnosis of transmural gangrene in only one patient. This patient was the only one whose death was directly related to this complication, notwithstanding timely surgical intervention. Four patients had severe and protracted diarrhoea, while four others exhibited no clinical symptoms at all. Ischaemic colonic lesions were found more often in patients who had been exposed to a period of preoperative shock, than in those who were operated on in a stable circulatory state (20.7 vs. 4.2%; P less than 0.05). It was also more common in patients in whom the patency of at least one hypogastric artery could not be preserved (36 vs 5.6%; P less than 0.02). Ligation of a patent inferior mesenteric artery was not in this study related to the development of ischaemic colonic disease, nor was a period of prolonged (greater than 1 h) cross clamping of the aorta. Postoperative diarrhoea was an early warning sign of ischaemic colonic disease in five of nine patients. Other clinical symptoms or signs were of no value at all in this respect.(ABSTRACT TRUNCATED AT 250 WORDS)