Indications for Anticoagulation in Patients With Prosthetic Heart Valves
All patients with mechanical valves require warfarin therapy. The risk of embolism is greater with a valve in the mitral position (mechanical or biological) than in the aortic position. With either type of prosthesis or valve location, the risk of emboli is higher in the first few days and months after valve insertion. Low-dose aspirin is recommended for all patients with prosthetic valves (see Table 1. For patients with mechanical valves, the addition of low-dose aspirin (80 to 100 mg/d) to warfarin therapy (INR 2.0 to 3.5) not only further decreases the risk thromboembolism but also decreases mortality due to other cardiovascular diseases. A slight increase in risk of bleeding with this combination should be kept in mind. Recommendations for Antithrombotic Therapy in Patients With Prosthetic Heart Valves Class I 1.First 3 months after valve replacement: Warfarin- INR 2.5 to 3.5 2.3 or more months after valve replacement: A. Mechanical valve AVR and no risk factor*: Bileaflet valve or...