Complementary distal arteriovenous fistula and deep vein interposition: a five-year experience with a new technique to improve infrapopliteal prosthetic bypass patency.

Abstract

In an attempt to improve graft patency results of prosthetic bypasses to infrapopliteal arteries, we used a new type of adjunctive technique that combines an arteriovenous fistula and vein interposition (AVF/VI). Over the past 5 years, 68 such reconstructions were performed in 62 patients with critical ischemia in whom a totally autogenous vein bypass was not feasible. Forty-seven patients (76%) had one or more failed ipsilateral infrainguinal bypasses. The AVF/VI was performed by transposing the central portion of the adjacent deep vein onto the side of the recipient artery. The distal end of a 6-mm polytetrafluoroethylene (PTFE) ringed graft then was anastomosed to the hood of the AVF. The segment of vein interposed between the PTFE graft and the recipient artery widened the anastomosis and improved the compliance mismatch. Simultaneous pressure measurements of the radial artery and the distal portion of the graft were obtained in all cases. Significant pressure gradients ranging from 35 to 70 mm Hg were detected in 26 bypasses (38%), which led to banding of the venous outflow that decreased the gradient to within 20 mm Hg. A gradient < or = 30 mm Hg was found in 28 bypasses (41%), and no banding was required if the absolute intragraft systolic pressure was > or = 100 mm Hg. Only 14 bypasses (21%) had no detectable pressure gradients. Twenty-six bypasses originated from femoral arteries, 34 from iliac arteries, and 8 from patent proximal grafts. The recipient arteries were the anterior tibial artery in 33 cases, posterior tibial in 17, peroneal in 15, dorsalis pedis in 2, and lateral plantar in 1. All patients began a regimen of heparin 6 to 8 hours after surgery and continued to receive chronic anticoagulation. Cumulative, 3-year assisted primary graft patency rates were 78%, 70%, and 62%, respectively. Cumulative 3-year AVF patency rates were 65%, 57%, and 46%, respectively. The 3-year limb salvage rate was approximately 78%. Adjunctive AVF/VI significantly improves infrapopliteal PTFE graft patency and limb salvage rates. The combination of a decreased compliance mismatch at the distal anastomosis and the abolishment of a large pressure gradient at the distal anastomosis while maintaining higher graft flow rates may have contributed to the improved results.