Reconstructive microsurgery has become a routine procedure in plastic surgery. Success rates in major centers range between 95 and 98%. In selected "high risk" cases, vein grafts are required to facilitate microsurgical anastomoses, as in complex defects of the lower leg, post ischemic syndrome (PIS) or following major tumor resections. The indications and results of vein grafts or A-V loops are demonstrated in these three groups. 25 patients with defects of the lower leg were operated using vein interposition grafts. Ten A-V loops were created prior to flap transfer. Three flaps had to be revised, only one flap was lost due to recurrent arterial thromboembolism from an injured proximal segment. Data show that vein grafts are clinically reliable and may be used without hesitation in appropriate clinical situations.