Vitamin K Antagonist Shows Protective Benefits in A-Fib

Vitamin K antagonist + acetylsalicylic acid dual therapy associated with increased bleeding risk
Vitamin K antagonist + acetylsalicylic acid dual therapy associated with increased bleeding risk

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 June 20 issue of 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). 

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"VKA monotherapy in patients with AF was associated with a lower risk of first-time MI and stroke than ASA monotherapy," the authors 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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