Bioprosthetic mitral valve thrombosis less than one year after replacement and an ablative MAZE procedure: a case report

Abstract

Occurrence of bioprosthetic valve thrombosis less than a year after replacement is very uncommon. Here, we describe a case of a 57 year old male, who presented 10 months after receiving a bioprosthetic mitral valve replacement with a two week history of dyspnea on exertion, worsening orthopnea and decreased exercise tolerance. Echocardiography revealed severe mitral regurgitation (MR), thrombosis of the posterior mitral leaflet, left atrial (LA) mural thrombus and a depressed left ventricular ejection fraction of twenty-five percent. Given severe clot burden and decompensated heart failure (New York Heart Association - NYHA class III) repeat sternotomy was done to replace the bioprosthetic mitral valve and remove LA mural thrombus. MR was resolved postoperatively. This brief report further reviews promoting factors, established guidelines and management strategies of bioprosthetic valve thrombosis.

Catastrophic late mitral bioprosthetic thrombosis

“…When bioprosthetic thrombosis occurs, it is generally associated with predisposing conditions such as a hypercoagulable diathesis, prior history of thromboembolic events, large left atrial size, AF, ventricular dysfunction, or a low output state. 1,2,4,5 In this case, there were no obvious risk factors for thrombosis: the left ventricular ejection fraction was normal, the left atrium was only mildly enlarged, and there was no hypercoagulable diathesis. Although freedom from long-term anticoagulation is a feature of bioprosthetic valve replacement, our case calls for a review of current anticoagulation guidelines following bioprosthetic valve replacement with a maze procedure.…”

“…Tissue bioprosthetic valves have been used extensively because long-term anticoagulation can be avoided as the risk of thrombotic complications after 3 months postoperatively is very low. 1,2 Nevertheless, the potential for thrombus formation and valve dysfunction remains because mild abnormalities in blood rheology favoring thrombosis have been described in patients with bioprostheses. [3][4][5] Oliver and colleagues 3 found bioprosthetic thrombosis in 10 of 161 (6.2%) patients with evidence of bioprosthetic valve dysfunction, suggesting that thrombosis could be a more frequent cause of bioprosthetic valve dysfunction than was previously thought.…”