Oversized vein grafts develop advanced atherosclerosis in hypercholesterolemic minipigs

An autologous reversed jugular vein graft was inserted end-to-end into the transected common carotid artery of ten hypercholesteroemic minipigs. The vein grafts were investigated 12-14 weeks later with ultrasound and angiograpy in vivo and microscopy post mortem.One minipig died during follow up (patent vein graft at autopsy), and one vein graft thrombosed early. In the remaining eight patent vein grafts, the mean (standard deviation) intima-media thickness was 712 μm (276 μm) versus 204 μm (74 μm) in the contralateral control internal jugular veins (P < .01). Advanced atherosclerotic plaques were found in three of four oversized vein grafts (diameter of graft > diameter of artery). No plaques were found in four non-oversized vein grafts (P < .05).Our model of jugular vein graft in the common carotid artery of hypercholesterolemic minipigs displayed the components of human vein graft disease, i.e. thrombosis, intimal hyperplasia, and atherosclerosis. Advanced atherosclerosis, the main cause of late failure of human aortocoronary vein grafts was only seen in oversized grafts. This finding suggests that oversized vein grafts may have detrimental effects on patient outcome.Aortocoronary vein graft disease can be divided into three discrete, but pathophysiologically linked, processes: thrombosis, intimal hyperplasia, and atherosclerosis [1]. Vein graft failure is usually caused by thrombosis. In early vein graft failure, thrombosis is largely related to technical factors limiting graft blood flow. Vein grafts, that do not occlude early, develop intimal hyperplasia which rarely causes significant stenosis in itself. Intimal hyperplasia may, however, form the soil in which atherosclerotic plaques can develop. Late aortocoronary vein graft failure is most often caused by rupture of an atherosclerotic plaque in the graft leading to thrombotic occlusion [2]. Thereby, the pathogenesis of late graft failure parallels the pathogenesis of atherothrombosis in native coronary arte