Recurrent native and prosthetic mitral valve thrombosis in idiopathic hypereosinophilic syndrome.

Hypereosinophilic syndrome (HES) is defined as a prolonged, unexplained peripheral eosinophilia. Endomyocardial fibrosis and mural thrombus formation are common occurrences such that patients are exposed to lethal thromboembolic complications. The valvular damage described is mainly related to iterative valve thromboses that are amenable to surgery.