The estimated prevalence of atrial fibrillation (AF) is 0.4%-1% in the general population and increases to 10% in those above 80 years of age (Go, 2001). AF accounts for 15% of strokes in persons of all ages and 30% in persons over the age of 80 years. All patients with nonvalvular atrial fibrillation are evaluated for oral antithrombotic therapy to prevent thromboembolism using the CHADS2 score. Those with a score above 2 are considered moderate or high risk and started on warfarin anticoagulation therapy, unless contraindicated. Warfarin is highly effective for reducing the rate of ischemic strokes but is limited by a narrow therapeutic range, drug and food interactions and frequent INR monitoring and dose adjustments.

The ROCKET AF trial has evaluated a new agent called rivaroxaban, an oral Factor Xa inhibitor that promises to provide more consistent and predictable anticoagulation than warfarin. Patel et al have shown that a once-daily fixed dose of rivaroxaban was non-inferior to dose-adjusted warfarin for the prevention of stroke or systemic embolism in nonvalvular atrial fibrillation.

Dabigatrin (direct thrombin inhibitor), Apixaban (a Factor Xa inhibitor) and now, Rivaroxaban are alternative oral anticoagulants that are at least as effective as warfarin, without the need for regular anticoagulation monitoring.

Full article:
PMID: 21830957

Title: Rivaroxaban versus warfarin in nonvalvular atrial fibrillation.
Authors: Patel MR, Mahaffey KW, Garg J, Pan G, Singer DE, Hacke W, et al
Journal Title: New England Journal of Medicine