DABIGATRAN VERSUS WARFARIN IN PATIENTS WITH ATRIAL FIBRILLATION: AN ANALYSIS OF PATIENTS UNDERGOING CARDIOVERSION

Title: Dabigatran Versus Warfarin in Patients With Atrial Fibrillation: An Analysis of Patients Undergoing Cardioversion
Date Posted: January 14, 2011
Authors: Nagarakanti R, Ezekowitz MD, Oldgren J, et al.
Citation: Circulation 2011;123:131-136.

Clinical Trial:
Randomized Evaluation of Long-Term Anticoagulant Therapy Warfarin, Compared With Dabigatran

Study Question:
Is anticoagulation with dabigatran adequate for stroke prevention in the setting of cardioversion of atrial fibrillation (AF)?

Methods:
This was a post-hoc analysis of 1,983 cardioversions in 1,270 patients enrolled in the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, in which 18,113 patients with AF were randomly assigned to anticoagulation with warfarin, dabigatran 110 mg twice daily (D110), or dabigatran 150 mg twice daily (D150). The number of cardioversions in the three groups ranged from 647 to 672, and 86% of the cardioversions were electrical. A transesophageal echocardiogram (TEE) was performed before cardioversion in 13%, 26%, and 24% of patients in the warfarin, D110, and D150 groups, respectively. The primary outcomes were stroke, systemic embolism, and major bleeding episodes within 30 days of cardioversion.

Results:
The stroke/systemic embolism rate did not differ significantly between the three groups (0.6%, 0.8%, 0.3% in the warfarin, D110, and D150 groups, respectively). The stroke/embolism rate did not differ between patients with and without a TEE in any of the three groups. The rates of major bleeding also did not differ significantly between the three groups (0.6%, 1.7%, and 0.6% in the warfarin, D110, and D150 groups, respectively).

Conclusions:
The risks of post-cardioversion stroke and major bleeding are similar with warfarin and dabigatran, whether or not a TEE is performed pre-cardioversion.

Perspective:
The results indicate that dabigatran is a reasonable alternative to warfarin for stroke prevention post-cardioversion. A possible advantage of warfarin is that therapeutic anticoagulation can be verified by measuring the international normalized ratio. With dabigatran, confirmation of anticoagulation with a laboratory test is not clinically feasible and one must rely on patients stating that they took the dabigatran as prescribed.

POSTED BY STEVEN ALMANY, MD