Non–Vitamin K Antagonist Oral Anticoagulants in the Treatment of Atrial Fibrillation

Atrial fibrillation (AF) increases a patient's stroke risk four- to five-fold. Anticoagulation with the vitamin K antagonist (VKA) warfarin reduces the risk of stroke by 67%, but warfarin carries a significant risk of major bleeding and has unpredictable pharmacodynamics with a narrow therapeutic window, necessitating frequent monitoring of its anticoagulant effect. The non–vitamin K antagonist oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, and edoxaban provide more predictable anticoagulant activity than warfarin with a lower risk of major bleeding, and each is noninferior to warfarin for the prevention of stroke. All have earned regulatory approval in the past eight years. At least one of the NOACs is approved for use in all patients with AF, except those with mechanical valves and rheumatic mitral valve disease, for whom warfarin remains the only option. Recent clinical trials have shown that antithrombotic regimens including NOACs are safe and effective in patients with AF who need potent antiplatelet therapy.