Rivaroxaban versus warfarin in Rheumatic Heart Disease-Associated Atrial Fibrillation (AF)
Connolly SJ et al invesigated whether rivaroxaban therapy would be noninferior to vitamin K antagonist therapy in patients with atrial fibrillation and echocardiographically documented rheumatic heart disease:
- enrolled patients with atrial fibrillation and echocardiographically documented rheumatic heart disease who had any of the following: a CHA2DS2VASc score of at least 2 (on a scale from 0 to 9, with higher scores indicating a higher risk of stroke), a mitral-valve area of no more than 2 cm2, left atrial spontaneous echo contrast, or left atrial thrombus
- patients were randomly assigned to receive standard doses of rivaroxaban or dose-adjusted vitamin K antagonist
- primary efficacy outcome was a composite of stroke, systemic embolism, myocardial infarction, or death from vascular (cardiac or noncardiac) or unknown causes
- primary safety outcome was major bleeding according to the International Society of Thrombosis and Hemostasis
Study results:
- of 4565 enrolled patients, 4531 were included in the final analysis
- mean age of the patients was 50.5 years, and 72.3% were women
- permanent discontinuation of trial medication was more common with rivaroxaban than with vitamin K antagonist therapy at all visits
- in the intention-to-treat analysis, 560 patients in the rivaroxaban group and 446 in the vitamin K antagonist group had a primary-outcome event
- survival curves were nonproportional
- restricted mean survival time was 1599 days in the rivaroxaban group and 1675 days in the vitamin K antagonist group (difference, -76 days; 95% confidence interval [CI], -121 to -31; P<0.001)
- a higher incidence of death occurred in the rivaroxaban group than in the vitamin K antagonist group (restricted mean survival time, 1608 days vs. 1680 days; difference, -72 days; 95% CI, -117 to -28)
- for the primary outcome of stroke, systemic embolism, MI, or death from vascular or unknown causes, there were 560 events in the rivaroxaban-treated patients and 446 events in those treated with a VKA (HR 1.25; 95% CI 1.10-1.41)
- in terms of individual components of the primary endpoint, rivaroxaban increased risk of death by 23% and risk of stroke by 37%
- no significant between-group difference in the rate of major bleeding was noted
The study authors concluded that:
- among patients with rheumatic heart disease-associated atrial fibrillation, vitamin K antagonist therapy led to a lower rate of a composite of cardiovascular events or death than rivaroxaban therapy, without a higher rate of bleeding.
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