Update on the Status of New Oral Anticoagulants for Stroke Prevention in Patients with Atrial Fibrillation

For decades vitamin K antagonists (VKA) have been the mainstay of treatment and prophylaxis of thromboembolism, in particular in primary prevention of systemic embolism associated with atrial fibrillation. Despite their efficacy, the use of VKA is associated with several limitations, including a narrow therapeutic window and a wide variability in the anticoagulant effect due to several drug-food and drug-drug interactions of VKA. The several limitations of VKA have resulted in their underuse for prevention of thromboembolic complications in patients with atrial fibrillation. Recently, new classes of oral anticoagulants have emerged: factor Xa (FXa) inhibitors and direct thrombin inhibitors. These new anticoagulants have a more predictable effect and eliminate the need for routine monitoring. Even though recent clinical trials have demonstrated the safety and efficacy of the new compounds, several unanswered issues must be addressed before conclusions can be drawn towards their potential to replace VKA.