Pathologic changes in aortic-coronary arterial saphenous vein grafts

This is a pathologic study of segments of saphenous vein used as a graft between the aorta and a coronary artery in the surgical treatment of coronary atherosclerosis. Except for an occasional case with thrombotic occlusion of the graft, no lesions were observed in grafts which had been in place for less than 1 month. In each of two grafts in place for 1 month, mild fibrous thickening of the intima was present. Eight grafts which had been in place for 3½ months or longer consistently showed lesions, either organized thrombi (two grafts) or intimal fibrotic proliferative lesion (six grafts). In this group, five of the six grafts with intimal fibrous proliferation showed near or complete occlusion of the lumen. The intimal fibrous proliferative lesion appears primarily to be a response to arterial pressure within the segment of vein. Obstructive atherosclerosis in the artery beyond the anastomosis with the graft may favor the development of the intimal lesion. The intimal lesion may progress rapidly according to the data in one of the cases. In this, patency of the graft demonstrated angiographically 3½ months after the operation was followed by near-complete occlusion of the lumen by the proliferative lesion 3 weeks following demonstration of patency.