Stroke Risk in Afib Reduced With Vitamin K Antagonist Therapy

HealthDay News — For patients with atrial fibrillation (AF), vitamin K antagonist (VKA) monotherapy is associated with reduced risk of first-time myocardial infarction (MI) and stroke compared with acetylsalicylic acid (ASA) monotherapy, according to a study published in the Journal of the American College of Cardiology.

Christina J Y Lee, MD, from Aalborg University in Denmark, and colleagues identified subjects with first-time AF diagnosed from 1997 to 2012 without history of coronary artery disease. The authors examined the incidence of first-time MI according to antithrombotic treatment. Data were included for 71,959 patients: 52% treated with VKA monotherapy, 35% with ASA monotherapy, and 13% with dual therapy (VKA + ASA).

The incidence of MI was 3% overall. The researchers found that the associated risk of MI was increased for ASA and dual therapy relative to the VKA-treated group (incidence rate ratios [IRR], 1.54 and 1.22, respectively). Dual therapy was associated with a significantly higher bleeding risk (IRR, 1.93). Relative to that of VKA therapy, the risk of stroke was significantly increased for ASA and dual therapy (IRR, 2.00 and 1.30, respectively).

“VKA monotherapy in patients with AF was associated with a lower risk of first-time MI and stroke than ASA monotherapy,” the researchers write. “Combination of ASA and VKA therapy was not associated with a lower risk of MI but was associated with increased bleeding risk.”

Several authors disclosed financial ties to pharmaceutical companies, including Bristol-Myers Squibb and Pfizer, both of which funded the study.

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Lee CJ, Pallisgaard JL, Olesen JB, et al. Antithrombotic therapy and first myocardial infarction in patients with atrial fibrillation. J Am Coll Cardiol. 2017 Jun 20;69(24):2901-2909. doi: 10.1016/j.jacc.2017.04.033.