Early Massive Left Atrial Thrombosis Following Mitral Bioprosthetic Valve Replacement Due to Suboptimal...

Atrial thrombi are rare after mitral valve replacement. We report a case of early postoperative massive left atrial thrombus following bioprosthetic mitral valve replacement. The patient, a 61-year-old woman, underwent mitral valve replacement, tricuspid ring annuloplasty, and left atrial plication and was discharged after achieving the target international normalized ratio (INR) with oral warfarin. At the two-month follow-up, the imaging findings indicated a giant left atrial thrombus measuring 79 × 55 × 45 mm, with a subtherapeutic INR of 1.18. Anticoagulation therapy was intensified with warfarin and bridged with subcutaneous nadroparin. The thrombus decreased after three weeks and resolved completely by three months, and subsequent echocardiography showed valvular function was satisfactory. This case underscores the importance of strict INR monitoring for high-risk patients, highlighting that warfarin is an effective treatment option for left atrial thrombi following mitral valve replacement.