Prevention of intestinal ischemia following abdominal aortic reconstruction

Prevention of ischemic bowel complications following abdominal aortic reconstruction requires identification of the patient at high risk for developing the complication; on precise, gentle, meticulous operative technique; on knowledge of bowel blood supply; on determining when the IMA must be reconstructed or when it can be safely ligated; and on methods of preserving or preventing damage to bowel blood supply. Patients at greatest risk for developing bowel ischemia following aortic reconstruction include those with a history of visceral angina, those with a patent IMA (40% to 52%), those being treated for ruptured aneurysm, those whose postreconstructive IMA stump mean blood pressures are less than 40 torr, those in whom Doppler flow signals cease following division or occlusion of the IMA, and those who have SMA occlusive disease and arteriographic documentation of IMA to SMA flow in the MMA (Table II). Patients at least risk include those in whom the IMA is already occluded (48% to 60%), those whose postreconstructive IMA stump pressures are more than 40 torr, those in whom Doppler flow signals persist after IMA occlusion, those who have flow in the MMA from the SMA to the IMA (provided this vessel is not injured), and those undergoing aortic reconstruction for aortoiliac occlusive disease.