[Thrombosis of prosthetic heart valves: diagnosis and management]

The incidence of prosthetic valve thrombosis (PVT) has been reported to be < 0.1-0.25%/year following isolated aortic valve replacement and < 0.1-2.5%/year after mitral valve implantation. In a consecutive series 10.3% of PVT occurred after an interruption of oral anticoagulant therapy for weeks or months, in 20.7% with inadequate low anticoagulation while in 34.5% of PVT cases intensity of the oral anticoagulant therapy showed significant ups and downs. There was an obvious increase of PVT incidences during the winter months, concomitant with increasing fibrinogen levels and plasma viscosity. The diagnosis of PVT can be made with a high specificity and sensitivity by analysis of the typical opening and closing clicks of the valve occluder. Parameters indicating chronic intravascular hemolysis, fluoroscopy and echocardiography are additionally helpful to confirm the diagnosis. The therapy of choice is prosthetic valve re-replacement. Systemic thrombolytic therapy may be an alternative in selected patient groups.