Anticoagulation for Mechanical Heart Valves

The global burden of valvular heart disease, which currently affects more than 100 million people, is growing with the aging population.1 Severe valvular heart disease is associated with major morbidity and mortality and often necessitates surgical valve replacement with a mechanical or a tissue valve. If the risk of surgery is prohibitive, transcathether valve replacement is another option.2 See accompanying article on page 942 Although mechanical heart valves (MHV) are more durable than tissue valves, they are more thrombogenic. Consequently, patients with MHV require long-term anticoagulation with vitamin K antagonists, such as warfarin.2,3 Although effective, warfarin has well-known limitations, including multiple drug and food interactions, and the challenges of coagulation monitoring and maintaining the international normalized ratio within the therapeutic range. Indeed, variability in the international normalized ratio is a major independent predictor of reduced survival in patients with MHV.4 Consequently, there is a need for effective anticoagulants for MHV patients with better pharmacological profiles than warfarin. Direct oral anticoagulants have replaced warfarin for many indications.5 These agents include dabigatran, which inhibits thrombin, and rivaroxaban, apixaban and edoxaban, which inhibit factor Xa. Despite the proven efficacy and safety of direct oral anticoagulants in the prevention of stroke in patients with atrial fibrillation, and in the prevention and treatment of venous thromboembolism, the unfavorable results of the RE-ALIGN (Randomized, Phase II Study to Evaluate the Safety and Pharmacokinetics of Oral Dabigatran Etexilate in Patients after Heart Valve Replacement) trial prompted the FDA to issue black-box warnings against the use …