THE CHALLENGES OF CHRONIC ANTICOAGULATION IN PATIENTS WITH PROSTHETIC HEART VALVES

Abstract

The vitamin K antagonists (VKA) had been the sole option to reduce or prevent the mechanical prosthetic valve thrombosis and thromboembolic phenomena for last several decades. Their chronic usage can lead to both bleeding as well as thrombotic complications. As the therapeutic window for the drug levels is very narrow, VKA therapy needs close monitoring and periodic blood testing (PT-INR). Patients have to follow bothersome diet restrictions. Patient-education and co-operation are paramount for maintaining the INR in the prescribed safe range. The recommendation for bridging therapy when the patients with mechanical valves are subjected to any procedure or surgery is not standardized and such instructions are often confusing to patients, family members and ill-trained health professionals. The management of special populations such as the pregnant and the elderly continue to be very challenging. Anticoagulation is generally avoided in those with bioprosthetic valves unless there is atrial fibrillation. An early clinical trial with rivaroxaban in patients with bioprosthetic valves and atrial fibrillation (RIVER trial) proved it to be non-inferior to warfarin. The role of newer oral anticoagulants in patients with prosthetic valves is the current focus of research. With large number undergoing transcutaneous aortic valve implantation (TAVI) which is a bioprosthetic device, deciding what constitutes the optimal anticoagulant for them has become an emerging clinical challenge.