Ischemic injury to the spinal cord and kidneys continues to be the major complication after resection of aneurysms involving the descending and proximal abdominal aorta. Our recent surgical experience with use of only a proximal clamp on the aorta to perform an "open" distal anastomosis has proved this technique to be safe and expeditious. We therefore compared our results using the technique of open distal anastomosis for aneurysm repair with those of the conventional two-clamp technique. Since January 1989, we have used the conventional two-clamp technique in 31 patients (group 1) and the technique of open distal anastomosis in 24 patients (group 2). No significant differences were noted between the two groups in terms of age, sex, cause of aneurysm, extent of aneurysm, or site of proximal cross-clamp. The average distal ischemic time was 31 minutes in group 1 patients and 26 minutes in group 2 patients. Renal insufficiency occurred in 8 of 31 patients in group 1 and in 0 of 24 patients in group 2 (p = 0.01). Neurologic complications occurred in 4 patients in group 1 and in 1 patient in group 2. Early mortality rates were similar for both groups (4 of 31 [13%], group 1; 4 of 24 [17%], group 2). Deaths were attributed to multiorgan failure and sepsis in 6 patients and coexisting coronary artery disease in 2 patients. Based on these results, we believe the technique of open distal anastomosis is safe and may improve the outcome in patients undergoing operation for descending thoracic aneurysms. Maintaining the distal circulation during aortic cross-clamping does not appear to be necessary in this experience.