Failure of arteriovenous fistulas at distal tibial bypass anastomotic sites.

Arteriovenous fistula formation has been advocated to increase the outflow for tibial and peroneal distal bypass grafts. Between January, 1981 and September, 1981, twenty-seven patients underwent thirty femoral to distal tibial or peroneal artery bypass procedures with creation of an arteriovenous fistula at the site of the distal anastomosis. Limb salvage was the primary indication for surgery in 97% of this severely ischemic group, with a mean ankle pressure index of 0.32. Despite high flow rates averaging 260 cc/minute and an initial patency rate of 97%, there were only two fistulas patent in intact limbs at the conclusion of the initial eight month follow-up period with one additional occlusion at 16 months. Limb salvage to the present (July 1983) was achieved in only six cases. In the patients with limb salvage, three bypass grafts remain patent despite fistula occlusion, two patients have occlusion of both graft and fistula but no rest pain, and a single patient has maintained both graft and fistula patency for 23 months. Creation of an arteriovenous fistula at the distal anastomotic site of tibial bypass procedures augments graft flow in the immediate post-op period; but, has very low long term patency rates and is not beneficial to graft patency or effectiveness.