The effect of vein diameter on patency of in situ grafts.

: In an attempt to evaluate the effect of vein diameter on early patency and long-term durability of in situ lower limb bypasses, we evaluated 195 femoral-distal, popliteal, and/or tibial bypasses constructed in 189 patients (153 men, 36 women), consisting of tibial bypasses in 116 (60%), and popliteal in 79 (40%). The operative angiograms were reviewed and the vein diameter was measured to the nearest 0.5 mm. Postoperative follow-up consisted of visits every three months where graft patency was assessed by physical examination and measurement of graft flow velocity and ankle-brachial indices. Conduits less than 3 mm had a higher rate of occlusion in the 0-30 day interval, but following that period performed satisfactorily. No conduit less than 2 mm was successfully utilized, because of inability to incise valves without injury in these tiny conduits. Following the perioperative period, conduit diameter does not affect the long-term durability of in situ bypass grafts.