Rivaroxaban Versus Warfarin in Nonvalvular Atrial Fibrillation

Study Questions:

Is rivaroxaban (a factor Xa inhibitor) as effective as warfarin for preventing strokes in patients with atrial fibrillation (AF)?

Methods:

In this multicenter, double-blind trial, 14,264 patients (median age 73 years) with AF and a CHADS2 score ≥2 (mean score 3.5) were randomly assigned to treatment with 20 mg/day of rivaroxaban (n = 7,131) or dose-adjusted warfarin (n = 7,133). The target international normalized ratio (INR) was 2-3. The median duration of follow-up was 23.6 months. The primary endpoint was the composite of stroke and systemic embolism.

Results:

The incidence of the primary endpoint did not differ significantly between the rivaroxaban (2.1%/year) and warfarin (2.4%/year) groups. The rate of major and nonmajor bleeding also did not differ significantly between the rivaroxaban (14.9%/year) and warfarin (14.5%) groups. However, the rates of fatal bleeding and intracranial hemorrhage were significantly lower in the rivaroxaban group (0.2 and 0.5%/year, respectively) than in the warfarin group (0.5% and 0.7%/year, respectively).

Conclusions:

The authors concluded that rivaroxaban is noninferior to warfarin for prevention of stroke/embolism in patients with AF, and is associated with a lower risk of fatal and intracranial hemorrhages.

Perspective:

As is the case with the direct thrombin inhibitor dabigatran, rivaroxaban is administered in a fixed dosage and does not require titration based on the INR. This is a major advantage over warfarin. Several studies have demonstrated that warfarin is underutilized in patients with AF who are at risk of stroke. The availability of more convenient and probably safer oral anticoagulants hopefully will promote improved utilization rates.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias, Novel Agents

Keywords: Incidence, Stroke, Intracranial Hemorrhages, Follow-Up Studies, Morpholines, Benzimidazoles, Warfarin, Atrial Fibrillation, Embolism


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