Thrombotic Obstruction of a Mechanical Prosthetic Valve in Tricuspid Position

A 43-year-old woman was admitted to the hospital for progressive exertional dyspnea and abdominal distention of several weeks' duration. Fourteen months earlier, she had undergone mitral and tricuspid valve replacement with 29- and 33-mm mechanical prostheses (St. Jude Medical, Inc.; St. Paul, Minn), respectively, for rheumatic mitral and tricuspid valve stenosis and regurgitation. Anticoagulation had been maintained by her local doctor; the international normalized ratio (INR) was 3.28 upon admission, although warfarin had been discontinued for a week because of hemorrhoidal bleeding about 2 months before this admission. Two-dimensional color Doppler echocardiography revealed a stenotic tricuspid valve prosthesis with mild regurgitation; the mean pressure gradient was 16.1 mmHg. Fluoroscopy showed that both cusps of the tricuspid prosthesis were stuck in a partially open position (Fig. 1). Fig. 1 Fluoroscopic examination shows that A) during the diastolic phase, the leaflets of both prosthetic valves were widely open, and B) during the systolic phase, both leaflets of the mitral valve prosthesis were closed, but those of the tricuspid valve ... Reoperation was performed with the patient under mild hypothermic cardioplegic cardiac arrest. The right atriotomy unexpectedly revealed a fixed fibrous rind that lined the whole right atrium. Therefore, a “rindotomy” was performed in order to expose the prosthesis. A plane of cleavage was created between the thrombus and the atrial wall and was progressively enlarged by blunt dissection. The thrombus was firmly adhered to the fibrous rind. After a total thrombectomy, the tricuspid valve prosthesis, which had been implanted in the anti-anatomic position, was exposed. The leaflets were in a fixed, partially open position due to thrombus (Fig. 2). The prosthesis was explanted and replaced with a new mechanical valve (St. Jude Medical, Inc.). After an uneventful recovery, the patient was discharged from the hospital on the 7th postoperative day; at that time, the INR was 2.8. Fig. 2 Intraoperative view shows A) the creation of the plane of cleavage between the thrombus and the atrium wall, B) the thrombus that was found after the fibrous rind was opened, C) the prosthetic valve that was exposed after thrombus removal, and ... The explanted prosthesis showed organized thrombi that involved both leaflets on the ventricular side (Fig. 3). Fig. 3 The explanted tricuspid valve prosthesis shows A) the stuck leaflets and some pannus, seen from the atrial aspect, and B) the organized thrombus that caused the leaflets to stick in a partially open position, seen from the ventricular aspect.