Bioprosthetic mitral valve thrombosis not prevented by novel oral anticoagulant and successfully treated with heparin

Abstract

We present the case of a bioprosthetic mitral valve thrombosis with formation of a large hypermobile mass on the posterior cusp and diffuse thickening of the remaining prosthetic cusps despite treatment with a novel oral anticoagulant for atrial fibrillation. Bioprosthesis thrombosis occurred 52 months after implantation. Prosthesis function was not relevantly affected by the thrombus and treatment with intravenous unfractionated heparin was initiated. Because of the large hypermobile mass, surgery was scheduled to prevent embolisation. Surprisingly, in the transoesophageal echocardiogram performed upon initiation of surgery, the thrombus could no longer be detected. All echocardiographic evidence of bioprosthesis thrombosis, including the large hypermobile mass and the diffuse cusp thickening, had disappeared during the 48 hours of intravenous treatment with unfractionated heparin. There was no clinical evidence of embolisation during the course of the hospitalisation. Follow-up after one month of anticoagulation with phenprocoumon showed intact bioprosthesis function with no evidence of recurrent thrombus.