Prosthetic valve thrombosis despite seemingly-adequate anticoagulation: the dangers of transient lapses in anticoagulation.

We report a 19-year-old woman with thrombosis of a prosthetic mitral valve that was most likely due to a short dip in anticoagulation in the days preceding the event. Interestingly, at presentation the patient was super-therapeutic, most likely a result of hepatic congestion as the heart began to fail, creating an illusion of thrombosis despite adequate anticoagulation.