A trial fibrillation (AF), the cardiac arrhythmia most frequently identified in clinical practice, becomes more prevalent as patients age. This condition is characterized by several devastating sequelae, including stroke and systemic thromboembolism (TE).1,2 Atrial fibrillation is a leading cause of neurologic disability and death depending on the severity of cardioembolic stroke, so oral anticoagulation is crucial for high-risk patients who have AF. Nonetheless, hemorrhagic sequelae of long-term anticoagulation are often seen during stroke prevention in patients who have AF. To date, several risk-scoring systems have shown modest predictive ability for endpoint events and have been well validated in recent studies. Two of the most widely used scores for risk prediction, CHADS 2 and CHA 2 DS 2 -VASc, guide the optimization of therapy in patients who have AF, particularly if those patients are artificially categorized into low-, moderate-, and high-risk groups (Table I).3-6 The classical and revised CHADS 2 score is cumulative on the basis of 6 clinical features: congestive heart failure, hypertension, diabetes mellitus, and age ≥75 years (counted as 1 point each), and a history of stroke or transient ischemic attack (2 points). 4,5 In comparison, the CHA 2 DS 2 -VASc score, proposed as a complement to the CHADS 2 score, ranges from 0 to 9 points; the clinical features are congestive heart failure or left ventricular ejection fraction ≤0.40, hypertension, age 65-74 years, diabetes mellitus, vascular disease, and female sex (1 point each), and age ≥75 years and prior stroke, transient ischemic attack, or thromboembolism (2 points each). 6 In both systems, patient stratification into 3 risk categories-wherein a 0 score is low risk, 1 is intermediate risk, and ≥2 is high risk-has received particular attention in embolic risk evaluation and is widely included in guideline recommendations. 2 The likelihood of an embolic event is closely related to the total points recorded for a given patient, and anticoagulation is advisable for patients with a score of 2 or more points.7 However, it is unclear whether anticoagulation should be recommended for intermediate-risk patients. When comparing