Arteriovenous anastomoses in the canine renal allograft

The effect of the allograft reaction on the vascular pattern of the kidney has been examined by a combination of stereomicro-angiography and histology on 21 transplanted dog kidneys; 9 autografts served as controls of the effect on the vessels by the operation. The allografts were removed 1–10 days after transplantation. Two to 3 days after the operation they exhibited histologic alterations that have been well documented by earlier workers. In allografts with evidence of rejection micro-angiographic examination disclosed a pathologic filling of the cortical veins indicative of arteriovenous shunting. In serial sections of micro-angiographed specimens pathologic arteriovenous communications were found in the cortex both pre- and postglomerularly. In auto-transplants removed after 2–29 days no such changes were found. The findings suggest that the renal allograft reaction can lead to the formation of pathologic arteriovenous anastomoses, a development that might well be a direct cause of the progressive tissue damage and functional impairment of the graft.