Pathobiology of saphenous vein grafts

Abstract

The long saphenous vein graft is the commonest conduit used for coronary artery bypass surgery. The short and long term success of the procedure depends on the patency of these bypass grafts. Vein graft disease can be divided into early (in the fi rst 30 days), intermediate (1 month to 1 year) and late (over 1 year). Early graft failure is usually caused by graft thrombosis and may be related to the surgical procedure, intermediate graft disease results from intimal hyperplasia while late graft pathology is a consequence of atherosclerosis. The etiology and pathological processes leading to these damaging eff ects on saphenous vein grafts are tackled in this review. The loss of endothelial integrity, the phenotypic changes in vascular smooth muscle cells and involvement of adventitial cells with collaboration of blood borne factors lead to occlusive pathology of saphenous vein grafts. The accelerated intimal hyperplasia and atherosclerosis are characteristic pathobiological features of these vein grafts. Inflammatory and immunological changes and graft thrombosis are mediated through the secretion and up regulation of growth factors, pro coagulant substances and other proteins arising from the vein wall cells and the blood owing through them.