Atherosclerosis of coronary artery bypass grafts and smoking.

Follow-up angiography was performed at selected intervals on 340 men who had undergone coronary artery bypass surgery. There were 1160 grafts, but 112 were excluded from study because they occluded shortly after the operation. After 5 years 115 patients were smokers and 225 were nonsmokers. The mean number of grafts per patient was similar in the two groups. We classified each graft according to irregularities in graft outlines and graft patency and found disease-free grafts in 39% of the smokers and 52% of the nonsmokers; the proportion of diseased or occluded grafts was greater in the smokers than in the nonsmokers. Our results do not identify the effect of smoking cessation after bypass surgery, but they do suggest that men who continue to smoke are at significantly greater risk of atherosclerosis and occlusion than nonsmoking men.