Spasm of a saphenous vein bypass graft. A possible mechanism for occlusion of the venous graft.

The phenomenon of spasm in a venous graft was documented by angiographic study of the graft. This phenomenon has not been reported previously, and, therefore, its frequency of occurrence is unknown. Spasm of a venous graft may prove to play a significant role in the early development of myocardial infarction, closure of the graft, or recurrence of angina after initially successful surgery for aortocoronary bypass when venous grafts remain patent.