Valve competence following experimental venous valve autotransplantation.

In canine experiments, venous patency and valvular competence were evaluated following transposition of a valve-containing vein segment, with an without a distal arteriovenous (AV) fistula. The effects of distal fistula size on valvular function were also examined. Autogenous valve-containing venous segment grafts were placed in the femoral position. With no adjuncts, 90% of the grafts showed either occlusion, severe extrinsic narrowing, or intraluminal filling defects on early venograms, although 75% of valves were eventually competent at death. Veins that had undergone thrombosis and recanalization were routinely incompetent. With a distal AV fistula, all veins remained patent and 86% demonstrated valve competence. With both an AV fistula and dextran 40, all veins remained patent and all valves were component. Separately, graded size of AV fistulas did not result in loss of valve competence. Following venous segment transposition, continuous venous patency appears necessary for eventual valvular function, and this is enhanced by both a distal AV fistula and dextran.