Below-knee reconstructions with the human umbilical veins--three-year results.

Arterial reconstructions in high flow, low resistance locations (aorta, iliac and common femoral arteries) usually have good long-term results. The late failure rate of below-knee arterial grafts is significantly higher because of their considerable length, the limited outflow bed and the small diameters (low flow, high resistance). In addition, there is the biomechanical stress with genuflexion. Apart from the operative technique and patient-specific vascular morphology, the long-term success of crural reconstructions depends largely on the type of arterial substitute. Based on a retrospective study, we have examined the influence of the bypass material in infragenicular reconstructions with distal popliteal, and with crural, insertion. The three-year patency (life-table method) in reconstructions with distal popliteal insertion was 83% for autologous vein grafts and 72% for umbilical vein grafts. In reconstructions with crural insertion patency was 62% for autologous veins, 50% for umbilical veins and 26% for PTFE grafts. Graft-specific early and late morphologic changes influencing the long-term performance have been analyzed by follow-up angiograms, and in some cases by macroscopic and histologic examination.