Dabigatran and Factor Xa Inhibitors for Stroke Prevention in Patients with Nonvalvular Atrial Fibrillation

Stroke is a major health problem worldwide, and is often fatal or associated with poor long-term outcomes. Atrial fibrillation (AF) is responsible for up to 20% of all strokes; and the risk of stroke in patients with AF increases with age. Although warfarin is well established for the prevention of stroke in patients with AF, it has some limitations, particularly a narrow therapeutic window, variable/unpredictable pharmacokinetic/pharmacodynamic properties, the restriction of vitamin K intake, and the need for regular coagulation monitoring. Therefore, warfarin is underused for stroke prevention in patients with AF. Several anticoagulants that inhibit thrombin or factor Xa have been developed. Dabigatran is a direct thrombin (factor Ha) inhibitor that overcomes many of the limitations associated with warfarin. The recent Randomized Evaluation of Long Term Anticoagulant Therapy study showed the noninferiority of 110 mg and 150 mg dabigatran twice daily, and the superiority of 150 mg dabigatran twice daily versus adjusted-dose warfarin in the prevention of stroke or systemic embolism in patients with nonvalvular AF. In addition, the rate of intracranial hemorrhage was much lower with both doses of dabigatran than with warfarin. Dabigatran was recently approved in Japan for the prevention of ischemic stroke and systemic embolism in patients with nonvalvular AF. Therefore, in this review, we discuss the properties of dabigatran and its clinical efficacy, safety, and positioning in the prevention of stroke. We also discuss precautions for the use of dabigatran and future perspectives with a view to reducing the risk of stroke with new oral anticoagulants, including factor Xa inhibitors in AF patients.