Infrainguinal aneurysm formation in arterialized autologous saphenous vein grafts.

True aneurysm formation in arterialized autologous veins is an unusual complication. We studied a patient with 2 aneurysms occurring in the mid and distal portion of an in situ femoropopliteal bypass. The first aneurysm led to graft occlusion 4 years after the primary intervention, requiring replacement of the ectatic graft segment. The graft was still patent when the patient was examined 7 years after the primary intervention and 3 years after the first aneurysm. In the mid portion of the graft, a true aneurysm measuring 5 by 8 cm had developed. The aneurysm was replaced by a reversed segment of the contralateral greater saphenous vein. Recovery was uneventful. Advanced atherosclerotic changes with extensive intimal fibroplasia, subendothelial cholesterol deposits, and ulcerations were revealed by means of histopathology of the aneurysm wall. Atherosclerosis is considered to be the main cause of aneurysm formation in vein grafts, but a review of the literature suggests the additional etiopathogenic factors should be further investigated.