A Rare Case of Early Left Ventricular Thrombus Development After Off-Pump Coronary Artery Bypass Grafting for Unstable Angina Pectoris With Reduced Left Ventricular Ejection Fraction

Left ventricular (LV) thrombus is a serious complication of myocardial infarction (MI) that can lead to a fetal systemic embolism. Although coronary artery bypass graft surgery (CABG) after MI is widely performed, to our knowledge, there are no reports of LV thrombus in the early postoperative period. Here, we report a rare case of a 70-year-old man who underwent off-pump coronary artery bypass grafting (OPCAB) for unstable angina pectoris with reduced left ventricular ejection fraction (LVEF). An LV thrombus (13 mm × 12 mm) was incidentally discovered on an echocardiography 7 days after OPCAB. We administered an oral anticoagulant (OAC) and observed resolution of the thrombus five months post-surgery. In the present case, factors such as low LVEF, infarcted lesion at the apex, and hypercoagulable state due to systemic inflammation after CABG likely contributed to LV thrombus development. This case highlights that LV thrombus is a potential complication early after CABG; thus, careful follow-up is required during the early postoperative period. Prophylactic anticoagulant administration in the early postoperative period should be considered for patients at particularly high risk for LV thrombus.