Progress for Stroke Prevention With Atrial Fibrillation

Abstract

Atrial fibrillation (AF) is both a common cardiac arrhythmia and a frequent cause of cardioembolic strokes. The prevalence of AF markedly increases with age and with the current population trends, the number of patients with AF is expected to continue to grow and may reach 12 million in the United States by 2050.1 AF accounts for up to 20% of all ischemic strokes and independently increases the risk of these events by up to 5-fold.2,3 Various cardiovascular risk factors do increase the risk of AF and given the continuing rise of obesity and resultant hypertension and diabetes, the future healthcare burden of AF-related strokes is likely to greatly increase. AF is arguably 1 of the best-studied causes of stroke with dozens of randomized trials that have led to well-established evidence-based recommendations regarding effective treatment modalities. Warfarin, a vitamin K antagonist, is currently the most commonly used oral anticoagulant. It has been used for decades, is inexpensive, and has standardized laboratory monitoring and reversal protocols. Warfarin is also exceedingly effective; a recent meta-analysis has shown it to reduce stroke by almost two thirds compared with placebo and to provide an almost 40% relative risk reduction compared with antiplatelet therapy.4 Warfarin, however, has several limitations that have led to underuse in the community. It has a very narrow therapeutic window with potentially life-threatening consequences from both under- and overdosing the medication. Bleeding, either systemically or intracranially, is the most feared complication; it has hindered a more wide-scale acceptance of this therapy, particularly among elderly patients. Maintaining most patients within that therapeutic window is challenging due to numerous drug and diet interactions and requires frequent and inconvenient blood testing and monitoring. Due to these difficulties, a portion of patients and physicians has never adequately adopted this therapy, which …