[Studies on inferior mesenteric arterial stump blood pressure and aortographic findings in surgical cases of abdominal aortic aneurysm: in relation to ischemic colitis].

: In 18 cases with unruptured abdominal aortic aneurysm, preoperative aortographic findings and the mean ratio of inferior mesenteric arterial stump blood pressure to systemic blood pressure (IMA/Syst. Pr. Ratio) were analyzed. In all cases IMA was ligated at operation because IMA/Syst. Pr. Ratio was more than 0.4, and one developed ischemic colitis. Preoperative aortogram was useful to identify meandering mesenteric artery and its flow direction to predict colon ischemia. IMA/Syst. Pr. Ratio following aortic reconstruction ranged from 0.41 to 1.0 with mean value of 0.70. In a case of ischemic colitis the ratio was the lowest value (0.5) except one case. Thus the ratio had diagnostic value to predict colon ischemia. Aortogram and IMA/Syst. Pr. Ratio were summed up to evaluate collateral circulation to colonic blood supply. Hypogastric arteries played an important role in some cases with intact IMA, and meandering mesenteric artery frequently in cases with occluded IMA. Consequently, it is important to preserve hypogastric arterial blood flow especially in the cases with intact IMA. In two cases whose internal iliac arteries were ligated bilaterally, IMA stump pressure was enough, and ischemic colitis was not encountered. The problems of peripheral vascular reconstruction in these two cases were also discussed.