Changes in grafts and coronary arteries after saphenous vein aortocoronary bypass surgery: results at repeat angiography.

We studied the patency of saphenous vein aortocoronary bypass grafts in nonconsecutive and consecutive subgroups of our first 600 patients. The patency rates were 87-93% within 1 month and 74-85% approximately 1 year after surgery. The attrition rate of grafts averaged 2.2% per year between 1 and 6 years. Early occlusion was due to thrombosis; occlusion at 1 year was caused by fibrous intimal proliferation of grafts, which also led to variable reduction in caliber and to significant (greater than 50%) segmental stenoses in 5-15% of patent grafts. The most important determinant of graft patency at 1 year was the runoff capacity of the recipient arteries, followed by the quality of the surgical techniques. Late occlusion was related to atherosclerosis that became manifest only after at least 2 years. Coronary atherosclerosis progressed in more than 50% of proximal segments of grafted arteries during the first year, but little additional deterioration occurred between 1 and 6 years. During the first year, only 10% of preexisting stenoses in nongrafted arteries showed progression of disease; progression in these vessels increased to 46% at 6 years and was no longer different, for preexisting lesions greater than 50%, from that of grafted arteries. A close correlation was observed between changes in grafts and in coronary arteries and long-term survival or relief of angina. Ninety-four percent of patients with all grafts patent and 98% with an optimal correction were alive at 6 years compared with 70% of patients without patent grafts or surgical correction. Changes in grafts or coronary arteries were observed in two-thirds of patients in whom functional deterioration occurred between 1 and 6 years, compared with 18% in whom improvement persisted after surgery.