Expert Commentary

Dabigatran Versus Warfarin in Patients With Atrial Fibrillation: An Analysis of Patients Undergoing Cardioversion

Rangadham Nagarakanti, MD

Cardiology Section,
Louisiana State University School of Medicine
New Orleans, LA

The vitamin K antagonist, warfarin, has been the mainstay of anticoagulant therapy for patients with atrial fibrillation (AF). However, it is difficult to manage due to the narrow therapeutic range, which necessitates frequent monitoring. Warfarin is also associated with numerous drug-drug interactions.1,2 Dabigatran is an orally active direct thrombin inhibitor, and the Randomized Evaluation of Long-Term Anticoagulation Therapy (RELY) trial (18,113 patients) compared its efficacy and safety to that of warfarin in patients who had nonvalvular AF and a risk of stroke.3 Patients were divided into three groups, each receiving either a twice-daily dose of 110 mg or 150 mg dabigatran, or warfarin. Treatment with 150 mg dabigatran, compared to warfarin treatment, was associated with lower rates of stroke and systemic embolism but similar rates of major hemorrhage. The current study is a post hoc analysis of dabigatran’s effect in the subset of 1270 of these patients who underwent cardioversion following > 3 weeks of anticoagulant therapy. Rates of stroke and systemic embolism at 30 days post-cardioversion were 0.8%, 0.3%, and 0.6%, respectively. These differences were not statistically different. Major bleeding rate tended to be greater in the group treated with 110 mg dabigatran versus warfarin (1.7% versus 0.6%, P=0.06), but not in the 150 mg dabigatran-treated group (0.6%). Thus, these data support the efficacy and safety of dabigatran as an alternative to warfarin for thromboprophylaxis in patients undergoing cardioversion. It is the largest study thus far to evaluate a novel anticoagulant in patients undergoing cardioversion for AF.4

References

  1. Ansell J. Warfarin versus new agents: interpreting the data. Hematology Am Soc Hematol Educ Program. 2010;2010:221-228.
  2. Mannucci PM, Franchini M. Old and new anticoagulant drugs: A minireview. Ann Med. Mar 2011;43(2):116-123.
  3. Connolly SJ, Ezekowitz MD, Yusuf S, et al. Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. Sep 17 2009;361(12):1139-1151.
  4. Nagarakanti R, Ezekowitz MD, Oldgren J, et al. Dabigatran versus warfarin in patients with atrial fibrillation: an analysis of patients undergoing cardioversion. Circulation. Jan 18 2011;123(2):131-136.
     
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