Antiplatelet Therapy for Stable Coronary Artery Disease in Atrial Fibrillation Patients on Oral Anticoagulant: A Nationwide Cohort Study
Background—Optimal long-term antithrombotic treatment of patients with coexisting atrial fibrillation (AF) and stable coronary artery disease (CAD) is unresolved and commonly a single antiplatelet agent is added to oral anticoagulation. We investigated the effectiveness and safety of adding antiplatelet therapy to vitamin K antagonist (VKA) in AF patents with stable CAD.
Methods and Results—AF patients with stable CAD (defined as 12 months from an acute coronary event) between 2002-2011 were identified. Subsequent risk of cardiovascular events and serious bleeding (requiring hospitalization) events were examined with adjusted Cox regression models according to ongoing antithrombotic therapy. A total of 8,700 patients were included (mean age 74.2 years; 38% females). During a mean follow-up of 3.3 years, crude incidence rates were 7.2, 3.8 and 4.0 events per 100 person-years for myocardial infarction/coronary death, thromboembolism and serious bleeding, respectively. Relative to VKA monotherapy, the risk of myocardial infarction/coronary death was similar for VKA plus aspirin (HR 1.12 [0.94-1.34]) or VKA plus clopidogrel (HR 1.53 [0.93-2.52]). The risk of thromboembolism was comparable in all regimens including VKA, while the risk of bleeding increased when aspirin (HR 1.50 [1.23-1.82]) or clopidogrel (HR 1.84 [1.11-3.06]) was added to VKA.
Conclusions—In AF patients with stable CAD, adding antiplatelet therapy on top of VKA is not associated with a reduction in risk of recurrent coronary events or thromboembolism, while risk of bleeding is significantly increased. The common practice of adding antiplatelet therapy to oral VKA anticoagulation in patients with AF and stable CAD warrants reassessment.
- Received July 2, 2013.
- Revision received January 4, 2014.
- Accepted January 13, 2014.