A 58-year-old man with postinfarction unstable angina was referred to the Department of Cardiovascular Surgery at the Saiseikai Kitakami Hospital for urgent coronary revascularization. The bilateral internal thoracic arteries (ITAs) were subsequently utilized to revascularize the myocardium. The left anterior descending artery (LAD) was revascularized with the in situ right ITA and the obtuse marginal artery was revascularized with the in situ left ITA. Although he was successfully weaned from cardiopulmonary bypass, he collapsed hemodynamically 15 min later. Thus, he underwent supplementary vein bypass grafting to the distal LAD and the diagonal artery. Postoperatively, his course was uneventful, apart from the perioperative infarction, and a coronary arteriogram demonstrated patent bilateral ITAs and vein graft. This case report emphasizes the importance of early recognition of this rare syndrome and advocates surgical treatment consisting of supplementary vein grafting.