Progression of atherosclerosis in coronary arteries and bypass grafts: ten years later.

Progression of atherosclerosis in aortocoronary saphenous vein grafts is frequent and is the predominant cause of late graft closure after CABG. Only approximately 60% of grafts remain patent between 10 and 12 years after surgery. Of patent grafts, 45% show angiographic evidence of atherosclerosis between 10 and 12 years after surgery and 70% of the atherosclerotic lesions reduce the graft lumen diameter by 50% or more. Atherosclerosis of saphenous vein grafts does not appear to be related to age, sex or cigarette smoking, but is associated with abnormalities of cholesterol lipoprotein fractions. Progression of atherosclerosis in the native coronary arteries is also very significant after CABG. Progression of CAD between 10 and 12 years after surgery occurs in approximately 50% of nongrafted arteries. Between 10 and 12 years after surgery, the rate of progression of disease in nongrafted arteries is not different from that of grafted arteries with patent grafts; however, progression is more frequent in grafted arteries with occluded grafts. The rate of progression is not related to age, sex, risk factors or extent of disease at baseline coronary arteriography. Progression of preexisting stenoses is more frequent than appearance of new stenosis. Progression is related to the severity of the preexisting stenosis only in nongrafted arteries. Finally, progression is related to alterations of left ventricular function during follow-up. Because of these progressive late changes, CABG should probably remain limited to patients with incapacitating anginal symptoms or to those with severe lesions for whom surgery might enhance long-term survival, such as patients with severe left main CAD and 3-vessel CAD.