Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and increases risk of stroke by nearly 5-fold. While warfarin has been employed successfully to reduce the risk of stroke in these patients, there are a number of challenges with therapy. These include the need for therapeutic monitoring due to variability in patient response, frequent dose adjustments, numerous drug-drug, drug-food, and drug-disease interactions, and a heightened risk of thrombosis and bleeding due to these issues. Current guidelines recommend that the vitamin K antagonists (VKA) or direct oral anticoagulants (DOACs) should be used for thromboprophylaxis in patients with nonvalvular AF at risk for stroke or systemic embolic events. The DOACs include the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban, and edoxaban. In clinical trials these agents consistently demonstrated a reduction in the risks of hemorrhagic stroke and intracranial hemorrhage compared to VKA. Clinicians now must decide if there are meaningful differences between these agents in order to prescribe the best agent for an individual patient. Therefore, it is critical for clinicians to go beyond information provided in manuscript abstracts, and gain an understanding of the similarities and differences in clinical trial design, patient enrollment, and statistical analysis.
Credits: Paul P. Dobesh; John Fanikos