Histological and biochemical studies of vascular autografts.

We have studied nine saphenous vein bypass grafts removed from patients at the time of a second operation. Two grafts had recanalized thrombus, four had severe intimal hyperplasia and three had atherosclerotic-like lesions. In cases of intimal hyperplasia biochemical analysis of graft wall lipid content revealed a pattern identical to normal saphenous vein. We have also compared the histology and lipid content of experimental vein and artery grafts in rhesus monkeys maintained on normal and atherogenic diets for fifteen months. Surgically unmanipulated arterial tissue in atherogenic diet animals developed uncomplicated lipid-containing intimal lesions. Grafts in these same animals developed more severe and more complicated lesions with an even higher lipid content. In this hyperlipidemic animal model the addition of hypertension produced no additional alterations in graft histology or lipid content.