Lower MI Risk with Direct Oral Anticoagulants in Atrial Fibrillation

By Will Boggs MD

NEW YORK (Reuters Health) - The risk of myocardial infarction (MI) in patients with atrial fibrillation (AF) was significantly lower with direct oral anticoagulants (DOACs) than with vitamin K antagonists (VKA), in a Danish registry study.

"There has been debate of whether the direct oral anticoagulants are as efficient as vitamin K antagonists in the prevention of myocardial infarction," Dr. Christina Ji-Young Lee from Aalborg University Hospital told Reuters Health by email. "Our study suggests that the direct oral anticoagulants are not inferior in the prevention of myocardial infarction."

The Danish national registries provided data on 31,739 patients with AF.

The standardized absolute one-year risk of MI was highest for VKA (1.56%) and significantly lower for the three DOACs: 1.16% for apixaban, 1.20% for dabigatran, and 1.07% for rivaroxaban, Dr. Lee and colleagues reported online July 3rd in the Journal of the American College of Cardiology.

The DOACs did not differ significantly from each other in the absolute risks of MI.

Results were similar after three years of follow-up.

Moreover, the one-year risk of the combined endpoint of cardiovascular mortality and MI was significantly lower for apixaban and dabigatran than for VKA.

Results were consistent for patients with and without prior ischemic heart disease and concomitant antiplatelet therapy.

"Our study is of an observational nature, and results should be interpreted with caution," Dr. Lee said. "However, our study is one of the largest studies investigating the risk of myocardial infarction with the use of oral anticoagulants in patients with atrial fibrillation and included the frail and older patients often excluded from randomized clinical trials."

"Even though patients with atrial fibrillation have a low incidence of myocardial infarction, physicians should still be aware of the higher risk and focus on reducing potential risk factors," she said. "Our study suggests that the concern of the use of direct oral anticoagulants and the risk of myocardial infarction should not be a contraindication to their use."

"Direct comparative studies of the DOACs with and without concurrent antiplatelet therapy are needed to determine optimum antithrombotic therapy for patients with AF who are at elevated risk of MI," the researchers suggest.

This study "helps to settle the dust around an eight-year-old debate concerning the risk of MI in patients receiving DOAC therapy (and specifically dabigatran) for stroke prevention in AF," write Dr. Stefan H. Hohnloser from J. W. Goethe University, Frankfurt, Germany and Dr. John W. Eikelboom from McMaster University, Hamilton, Ontario, Canada in a related editorial. "Based on the large and consistent body of evidence now available, clinicians can use dabigatran with even greater confidence in AF patients, including those with a history of coronary artery disease and prior MI."

Four of the 10 authors of this report and both authors of the editorial have various relationships with manufacturers of DOACs.

SOURCE: https://bit.ly/2J4W1g0 and https://bit.ly/2L05Q0D

J Am Coll Cardiol 2018.

(c) Copyright Thomson Reuters 2018. Click For Restrictions - https://agency.reuters.com/en/copyright.html

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