Thrombotic prosthetic valve dysfunction requiring valve re-replacement after mitral valve replacement for caseous calcification with hypereosinophilic syndrome: a case report.

Background: Caseous calcification of the mitral annulus (CCMA) and hypereosinophilic syndrome (HES) are both associated with thrombotic tendencies. Caseous calcification of the mitral annulus may cause mitral valve regurgitation (MR), which may necessitate surgical intervention, depending on its severity. Given the absence of reported cases combining CCMA and HES, the optimal target range for anticoagulation therapy after mitral valve replacement remains to be established. Case summary: A 64-year-old man with CCMA complicated by HES was admitted due to heart failure and severe MR. The patient underwent mitral valve replacement with a mechanical valve. Despite standard anticoagulation therapy, prosthetic valve dysfunction had developed because of thrombosis. Intraoperative transoesophageal echocardiography revealed a closed stuck valve, necessitating valve re-replacement. A bioprosthetic valve was selected. Discussion: In cases of CCMA complicated by HES, the target of anticoagulation therapy is unclear. This case demonstrated that more intensive anticoagulation is required because of the thrombogenic risk of CCMA and HES. The mechanism of calcification due to eosinophilia has been suggested, and the relationship between eosinophilia and CCMA remains a subject for future research.