Changes in Grafted and Nongrafted Coronary Arteries Following Saphenous Vein Bypass Grafting

Abstract

Progression of disease in the native coronary arterial circulation was studied in 121 patients who underwent saphenous vein bypass graft surgery at the University of Alabama Medical Center, Birmingham, between 1969 and 1972, and who had a second coronary arteriogram at a mean interval of 11.7 months later. Two hundred thirteen arteries (10 triple, 74 double, 37 single) were grafted and 148 were not. Graft patency rate was 72%. Stenotic obstructive lesions in defined arterial segments and major branches were recorded for each artery at each examination. Pre and postoperative arteriograms were reviewed at the same time. Disease was expressed as "% stenosis" of each segment or branch examined. An arterial score, which was the sum of segments and branches seen on each occasion, was calculated for each artery and the scores were compared. New total occlusion, new obstructive lesions, and progression of pre-existing lesions were five times more frequent in grafted than in nongrafted arteries with comparable initial disease. New and progressive lesions were encountered with the same frequency in arteries with patent and occluded grafts. They occurred more frequently in segments proximal to the graft than in distal segments. Arteries with moderate (less than 75%) and arteries with severe (75-99%) stenosis had similar progression rates. Only 2% of segments of ungrafted arteries showed new total occlusions as compared to 60% of grafted arteries. The arterial score fell by 34% in grafted arteries and did not change in nongrafted arteries. These findings suggest that significantly fewer branches and segments of grafted arteries are seen following bypass grafting. New totally occlusive lesions are considerably more frequent in grafted than in nongrafted arteries and are not related to graft patency at one year after surgery. Disease progression in ungrafted vessels is relatively slow. These changes in the coronary arteries should be considered when assessing patients, particularly those with moderate degrees of stenosis, for bypass grafting.