Venous ischemia as a cause of ureteral necrosis in transplanted ureters

Urologic complications after pediatric renal transplantation can adversely effect the outcome and may result in decreased graft survival. Efforts to prevent these complications are worthwhile. This study investigates the incidence of these complications in a clinical transplant program and reports on an animal model used to investigate one possible cause.

In the clinical study, the results of a pediatric renal transplant program at a large children's hospital for a 5(1/2)-year period were reviewed with special attention paid to patients suffering ureteral necrosis. In the experimental study, 9 swine underwent laparotomy, bilateral complete infrahilar ureteric dissection, and extravesical ureteroneocystostomy. On the left side only, the renal and adrenal veins were ligated. The arterial supply remained intact. The right side did not undergo vessel ligation and served as the control. Three pigs each were killed at 3, 8, and 15 days. Kidneys, ureters and a cuff of bladder were examined histologically.

In the clinical study 75 renal transplants were performed with a total of 5 cases of early ureteral necrosis. Two of these 5 displayed venous congestion and ischemia, and 2 were associated with kidneys displaying primary nonfunction of the graft. Seventy-one of 75 grafts are continuing to function. One of the 4 early graft losses also had an ischemic ureter. In the experimental study all right kidneys and ureters were normal. All left kidneys had complete hemorrhagic necrosis. Necrosis also was found in 5 of 9 proximal left ureters and in 7 of 9 distal left ureters. Viable left ureters displayed moderate to severe submucosal and periureteric hemorrhage. Four of 9 ureters displayed more damage distally than proximally. The extent of necrosis was similar at 3, 8, and 15 days.

In both clinical and experimental studies, venous congestion and subsequent ischemia have been shown to be important causes of ureteral necrosis after renal transplantation.