Myocardial Ischemia Events in Patients With Atrial Fibrillation Treated With Dabigatran or Warfarin in the RE-LY Trial

Study Questions:

Does dabigatran increase the risk of myocardial infarction (MI) or ischemia?

Methods:

This was a post hoc analysis of data from the RE-LY trial, in which 18,113 patients with atrial fibrillation (AF) and ≥1 risk factor for stroke were randomly assigned to treatment with warfarin or dabigatran (110 or 150 mg twice daily). Myocardial ischemic events were defined as MI, unstable angina, or cardiac arrest.

Results:

The annual MI rates in the warfarin, dabigatran 110 mg, and dabigatran 150 mg arms were 0.64%, 0.82%, and 0.81%, respectively. These rates did not differ significantly nor did the composite annual rates of MI, unstable angina, cardiac arrest, and cardiac death (3.41%, 3.16%, and 3.33%, respectively).

Conclusions:

The authors concluded that dabigatran does not significantly increase the risk of myocardial ischemic events.

Perspective:

This study was prompted by a trend in the RE-LY study towards more MIs in the dabigatran arms than in the warfarin arm. This more detailed analysis demonstrates that differences in MI rates between the study drugs were not significant. It should be kept in mind that RE-LY was not powered to detect differences in MI rates, and a small increase in risk of MI with dabigatran cannot be ruled out. However, the MI rate is much lower than the stroke rate in patients with AF. Therefore, the benefits of dabigatran over warfarin in terms of stroke and bleeding risks would seem to outweigh any possible small increase in the risk of MI.

Clinical Topics: Anticoagulation Management

Keywords: Myocardial Infarction, Stroke, Myocardial Ischemia, Warfarin


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