Stroke in atrial fibrillation: Review of risk stratification and preventive therapy

Atrial fibrillation (AF) is a leading preventable cause of ischemic stroke for which early detection and treatment are critical. The risk of stroke in people with AF can be stratified by the use of such validated prediction instruments such as CHADS(2) or CHA(2)DS(2)-VASc. The CHA(2)DS(2)-VASc adds to the evaluation of the risk of stroke by reliably identifying patients at very low risk. Additional points are assigned for an additional age category of 65-74 years (1 point), female sex (1 point), and vascular disease other than cerebrovascular disease (1 point). Two points are awarded for age >= 75 years. The risk of stroke increases according to point score: 0.5% per year (0 points), 1.5% per year (1 point), 2.5% per year (2 points), 5% per year (3 points), 6% per year (4 points), and 7% per year (5-6 points). For decades, Vitamin K antagonists were the only class of oral anticoagulants available to clinicians for the prevention of stroke in AF. However, new oral anticoagulants (NOACs), such as apixaban, dabigatran, and rivaroxaban, are currently available and have proved to be safe and effective in preventing stroke in patients with nonvalvular AF. In addition, a nonpharmacologic procedure like left atrial appendage occlusion is a possible option in selected patients. In this article, we have reviewed the stratification of stroke risk in AF, prevention of stroke in nonvalvular AF, warfarin versus NOACs, weighting risk of bleeding versus stroke risk when deciding on the anticoagulation protocol in patients with AF, and the use of nonpharmacologic therapy for stroke prevention.