In a case-control study of 63 patients undergoing major nonthoracic vascular surgery with prior cardiac catheterization, we found total coronary occlusion serving viable myocardium and "nonobstructive" lesions to be the most common proximate cause of perioperative myocardial infarction or death. The extent of coronary disease by several measures was significantly correlated with adverse outcome, and prior bypass surgery appeared to be protective.