Emergent operation for aneurysm of the left main coronary artery presenting acute myocardial infarction.

We report an emergent operation on a 37-year-old man presenting with acute myocardial infarction with an aneurysm of the left main coronary artery. A preoperative coronary angiogram revealed a large saccular aneurysm of the left main coronary artery and complete occlusion of the left anterior descending artery. Emergent coronary artery bypass graftings to the left anterior descending artery with the left internal thoracic artery and the circumflex artery with the saphenous vein were performed, followed by the ligation and exclusion of the aneurysm of the left main coronary artery. The postoperative course was uncomplicated and the patient did well. Although the etiology of the aneurysm was not investigated, it was suspected to be a congenital aneurysm.