Early massive thrombosis of a mechanical mitral valve.

We report the case of a 74-year-old woman who underwent an elective procedure to replace her mitral valve with a 27-mm CarboMedics bileaflet valve (CarboMedics, Inc.; Austin, Tex) to correct mitral incompetence. Massive thrombosis of the prosthesis was clinically evident on the 6th postoperative day, despite administration of warfarin therapy according to our usual protocol. After an unsuccessful attempt at thrombolysis with recombinant tissue plasminogen activator, the mechanical prosthesis was replaced with a bioprosthesis. The cause of the thrombosis is unknown, but transient suboptimal anticoagulation is assumed to be responsible. Although very early massive valve thrombosis is a rare occurrence, it is a known risk of prosthetic valve implantation. Antiplatelet therapy, in addition to the usual warfarin anticoagulation, can help to prevent it. If thrombosis is diagnosed, it can be managed by thrombolysis or, when thrombolysis is unsuccessful, by reoperation. Transesophageal echocardiography is fundamental in the diagnosis and management of this sequela.