Switching from a Vitamin K Antagonist to Rivaroxaban Appears to Be Safe

Joel M. Gore, MD

In a substudy of ROCKET AF, outcomes with warfarin and rivaroxaban for atrial fibrillation were similar whether or not patients were previously taking a VKA.

In the ROCKET AF trial, rivaroxaban (20 mg) was noninferior to adjusted-dose warfarin for prevention of thromboembolic events in 14,264 patients with atrial fibrillation (NEJM JW Cardiol Aug 10 2011). In a prespecified subanalysis, investigators compared the efficacy and safety of rivaroxaban versus warfarin among patients who had been taking vitamin K antagonists (VKAs) for ≥6 weeks at screening (55%) and those who had not (45%).

At baseline, VKA-experienced patients were older, were less likely to be women, had lower blood pressure, and had lower CHADS2 scores than VKA-naive patients. During approximately 2 years of follow-up, nearly one quarter of patients discontinued study treatment. Stroke and cardiovascular event rates were lower in the VKA-experienced than in the VKA-naive patients regardless of treatment allocation, and rivaroxaban was noninferior to warfarin regardless of prior VKA use. During the first 7 days after treatment initiation, rivaroxaban was associated with increased bleeding rates compared with warfarin in both VKA-experienced and VKA-naive patients. After 30 days, bleeding rates were lower in the rivaroxaban group than in the warfarin group in VKA-naive patients and similar in both treatment arms in VKA-experienced patients.

CITATION(S):

Mahaffey KW et al. Clinical outcomes with rivaroxaban in patients transitioned from vitamin K antagonist therapy: A subgroup analysis of a randomized trial. Ann Intern Med 2013 Jun 18; 158:861.