Left coronary ostial embolization by a migrated pledget after redo mitral valve replacement: a case report

Redo mitral valve replacement is associated with increased surgical complexity and perioperative risk. Acute coronary obstruction caused by retained surgical materials is extremely rare but can lead to fatal myocardial ischemia. A 64-year-old woman with prior bioprosthetic mitral valve replacement underwent redo surgery for severe intraprosthetic regurgitation. Shortly after separation from cardiopulmonary bypass, she developed ventricular fibrillation and severe myocardial dysfunction, requiring reinstitution of bypass and subsequent extracorporeal membrane oxygenation (ECMO). Coronary angiography revealed a thrombus-like lesion at the left coronary ostium with preserved TIMI grade 3 flow; however, repeated aspiration failed to retrieve thrombotic material. Intravascular ultrasound demonstrated a solid non-thrombotic intraluminal obstruction. Surgical exploration confirmed complete occlusion of the left coronary ostium by a retained pledget from the previous operation. Removal of the pledget resulted in rapid improvement of myocardial contractility, and ECMO was successfully discontinued the following day. Coronary ostial embolization by retained pledget is a rare but life-threatening complication after redo mitral valve surgery. Early recognition, intravascular imaging, and timely surgical intervention with mechanical circulatory support are crucial for favorable outcomes.