# Early Massive Left Atrial Thrombosis Following Mitral Bioprosthetic Valve Replacement Due to Suboptimal Anticoagulation: A Case Report

## TL;DR

A patient developed a large blood clot in the left atrium after heart valve surgery due to inadequate blood thinner use, but it resolved with treatment.

## Contribution

This case highlights the risk of suboptimal anticoagulation after bioprosthetic mitral valve replacement and the effectiveness of warfarin therapy.

## Key findings

- A 61-year-old woman developed a massive left atrial thrombus after mitral valve replacement with subtherapeutic INR.
- Intensified anticoagulation therapy led to complete resolution of the thrombus within three months.
- Strict INR monitoring is crucial for preventing thrombosis in high-risk patients following valve replacement.

## Abstract

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.