Oral Antithrombotic Agents for the Prevention of Stroke in Nonvalvular Atrial Fibrillation

Abstract

T he rate of stroke among adults with atrial fibrillation (AF) varies widely, ranging between 1% and 20% annually (mean 4.5% per year) depending on comorbidities and a pa-tient's history of prior cerebrovascular events. 1 Stratification of stroke risk is important, because the major risk of antithrombotic medications used to lower the incidence of AF-related stroke is bleeding. For warfarin, this involves balancing a bleeding risk of 1% to 12% per year against the risk of ischemic events, with its use generally reserved for individuals at greatest thromboem-bolic risk. 1–3 The advent of several new antithrombotic agents offers alternatives to warfarin and may lower the threshold for thromboembolic risk for initiating therapy in patients with AF. In this update to the American Heart Association/American Stroke Association (AHA/ASA) " Guidelines for the Primary Prevention of Stroke " 4 and the prevention of stroke in patients with stroke or transient ischemic attack (TIA), 5 we review recent trials testing the safety and efficacy of a thrombin inhibitor (dabigatran) and 2 factor Xa inhibitors (rivaroxaban and apixa-ban) in preventing stroke in patients with AF, and we revise management recommendations. 4,5 Recommendations follow the AHA's and the American College of Cardiology's methods of classifying the level of certainty of the treatment effect and the class of evidence (Table 1).