Antithrombotic prophylaxis in elderly patients with atrial fibrillation.

The burden of atrial fibrillation (AF) worldwide is projected to increase substantially over the next few decades in part due to an aging population. AF increases the risk of stroke approximately fivefold. The population-attributable risk for stroke by age is considerable: 1.5% for those individuals 50 to 59 years of age compared with 23.5% for those > or =80 years of age. Vitamin K antagonists (VKAs) like warfarin have been shown to greatly reduce the risk of stroke. However, despite their proven efficacy, VKAs remain underused, particularly among elderly patients with AF. The preponderance of evidence from randomized trials and observational studies attests to higher bleeding rates among elderly individuals with AF. Antiplatelet therapy is not effective for stroke prevention in AF and is also associated with significant bleeding risk. Strategies to optimize the effectiveness of VKAs and improve their safety profiles among elderly patients in clinical practice are directly needed. An understanding of the pathological changes that predispose to hemorrhage, hazards of polypharmacy, and factors that contribute to variability in dose response will facilitate a more informed use of these medications in clinical care. Thieme Medical Publishers.