Occlusion of Coronary Arteries after Vein Bypass

The coronary arteries of 100 patients were radiographically visualized by selective injection of contrast material. Findings in the three main arteries (left anterior descending, right, and circumflex arteries) were analyzed before and after aortocoronary-saphenous vein graft surgery. Proximal coronary artery stenosis progressed to complete occlusion in almost half the patients on whose stenotic arteries a graft had been placed. The incidence was higher than that observed in nongrafted arteries during the "natural" course of the disease. The frequency of occlusion in grafted coronary arteries was higher in severely stenotic than in moderately stenotic arteries. The fact that the occlusion occurred more often with a patent graft than with a closed graft suggests a hemodynamic component in its pathogenesis. The study indicates that in many patients the prognosis must remain linked to patency of the bypass graft.