Reoperative minimally invasive mitral valve replacement for bovine pericardial valve thrombosis secondary to idiopathic hypereosinophilic syndrome.

Bioprosthetic mitral valves rarely obstruct. We present an older woman who presented with rapidly progressive dyspnea 4 years after bovine mitral replacement. Investigations demonstrated severe mitral stenosis with large, obstructive masses within the previous mitral prosthesis and an elevated eosinophil count. She underwent urgent reoperative mitral replacement and tricuspid valve repair through a 4-cm right minithoracotomy under hypothermic, fibrillatory arrest. Pathologic analysis revealed eosinophilic infiltrates in the obstructive masses and normal endomyocardial biopsies. She made an uneventful recovery and was discharged on steroids to suppress the eosinophilia. Repeat echocardiography demonstrated a well-functioning porcine valve without leaflet restriction or obstruction.