Lipid peroxidation: a possible factor in late graft failure of coronary artery bypass grafts

Atherosclerosis is the paramount cause of late vein graft failure after coronary artery bypass grafting. Lipid peroxidation, which may play a significant role in the initiation and progression of atherosclerosis, was examined in segments of vein grafts (n = 6) harvested at reoperation for coronary disease. These were analyzed for cholesterol, phospholipid, triglyceride, and lipid peroxides. Nonatherosclerotic vascular tissues, including coronary arteries (n = 6), saphenous veins (n = 9), and donor aortic specimens (n = 11) were analyzed for comparison. Risk factors for atherosclerosis including elevated serum cholesterol and triglycerides, smoking, and hypertension were more frequent in patients with coronary artery disease compared to organ donors. Lipid peroxides were elevated in explanted vein grafts when compared to either saphenous vein, coronary artery or donor aorta. Lipid peroxides were not significantly different in saphenous vein when compared to coronary artery, but levels in both of these tissues were greater than in donor aorta. Although increased levels of lipid peroxides in explanted veins may simply reflect morphologic changes in these grafts, the known effects of lipid peroxides on a number of biochemical events suggest that they may contribute directly to graft failure after coronary artery bypass grafting.