ST-Elevation Myocardial Infarction Induced by Acute Occlusion of an Ostial Left Intermammary Artery Graft Occurring 13 Years After Coronary Artery Bypass Graft Surgery

The left intermammary artery (LIMA) graft is commonly used in coronary artery bypass grafting (CABG) to left anterior descending (LAD) because of its superior long-term patency. Acute occlusion of the LIMA causing ST-elevation myocardial infarction (STEMI) in the late postoperative period is rare, and its pathological mechanism is unclear. We present a case of acute occlusion of the LIMA in a 87-year-old woman who underwent CABG surgery 13 years previously. She was transferred to our hospital because of acute chest pain. Electrocardiography showed ST-elevation in anterior leads. Emergency coronary angiography revealed total occlusion of proximal LAD segment and the ostial LIMA (Figure). Therefore, we judged that the LIMA occlusion was causing anterior STEMI, and performed emergency percutaneous intervention. We successfully implanted a drug eluting stent at the culprit lesion and final angiography showed good reperfusion. Although the LIMA graft is expected long-term patency, early recognition of the possibility of LIMA occlusion might be necessary in patients with AMI after CABG surgery.