Antithrombotic Treatment in Patients With Heart Failure and Associated Atrial Fibrillation and Vascular Disease: A Nationwide Cohort Study

Study Questions:

What impact does atrial fibrillation (AF) and antithrombotic treatment have on prognosis in patients with heart failure (HF) as well as vascular disease?

Methods:

The study investigators categorized AF status as prevalent incident or no AF in hospitalized patients with HF and co-existing vascular disease (coronary artery disease or peripheral arterial disease) followed from 1997-2009. Using Cox regression models, they assessed the risk of thromboembolism (TE), myocardial infarction (MI), and serious bleeding, with antithrombotic therapy and AF as time-dependent variables.

Results:

The study cohort was comprised of 37,464 patients (mean age, 74.5 [standard deviation, 10.7] years; 36.3% females) with a mean follow-up of 3.0 years, during which 20.7% were noted to have prevalent AF and 17.2% as incident AF. When compared to vitamin K antagonist (VKA) in prevalent AF, VKA plus antiplatelet was not associated with decreased risk of TE (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.73-1.12) or MI (HR, 1.11; 95% CI, 0.96-1.28), whereas bleeding risk was significantly increased (HR, 1.31; 95% CI, 1.09-1.57). Corresponding estimates for incident AF were HR, 0.77 (95% CI, 0.56-1.06), 1.07 (95% CI, 0.89-1.28), and 2.71 (95% CI, 1.33-2.21), respectively. They found that in no AF patients, there were no statistical differences between antithrombotic therapies on TE or MI risk, whereas bleeding risk was significantly raised for VKA with or without single antiplatelet therapy.

Conclusions:

The study authors concluded that in AF patients with co-existing HF and vascular disease, adding a single antiplatelet agent in addition to VKA therapy is not associated with additional benefit on thromboembolic or coronary risk, but notably increased bleeding risk.

Perspective:

This registry study reports that using antiplatelet agents in addition to warfarin, in AF patients with co-existing HF and vascular disease, not only does not offer incremental benefit in preventing thromboembolic or coronary risk, but also increases bleeding risk. In order to better characterize the relative merits of this combination therapy, prospective studies are needed to determine whether indeed this bleeding risk is related to the intensity of anticoagulation. The benefits and risks of adding antiplatelet therapy to oral direct inhibitors of anticoagulation (such as dabigatran, apixaban, and rivaroxaban) in this patient population also need to be evaluated.

Clinical Topics: Anticoagulation Management, Heart Failure and Cardiomyopathies, Vascular Medicine, Novel Agents, Acute Heart Failure

Keywords: Myocardial Infarction, Coronary Artery Disease, Morpholines, Platelet Aggregation Inhibitors, Warfarin, Pyrazoles, Peripheral Arterial Disease, Thromboembolism, Benzimidazoles, Heart Failure, Risk Assessment, Pyridones


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