Progression of obstructive coronary artery disease 5 to 7 years after aortocoronary bypass surgery.

Changes in the native coronary circulation were evaluated 5 to 7 years (72 +/- 10 months) after aortocoronary bypass surgery in 108 patients; 104 had had previous angiographic controls between 6 and 18 months following surgery. Coronary artery narrowings were graded on a scale of 0 to 6, 0 being normal, grade 1 and 2, < or = 50%; grade 3, 51-75%; grade 4, 76-90%; grade 5, 91-99% narrowing and grade 6 total occlusion. Progression of disease was significant when a preexisting stenosis increased at least 1 grade or a new lesion > 50% developed. Nongrafted vessels were compared to arteries with patent or occluded grafts. During the first year following surgery, the rate of progression was much higher in grafted arteries with patent or occluded grafts than in nongrafted arteries 157 and 53% vs 9.5% respectively, P < 0.001). During the subsequent period of approximately 5 years, however, grafted arteries did not change, whereas the rate of progression in nongrafted arteries increased from 9.5 to 46%. At 5 to 7 years after surgery, grade 1 and 2 (< or = 50%) narrowings progressed slightly more frequently in grafted arteries because of surgically related events. However, for narrowings > 50% and for new lesions, there was no difference in the rate of progression between grafted and nongrafted vessels. In conclusion, the rate of progression of atherosclerosis in nongrafted coronary arteries is important. At 5 to 7 years after surgery, there is little or no difference in the severity of the disease in the proximal segments of grafted and nongrafted coronary arteries.