Current Status of Stroke Risk Stratification in Patients With Atrial Fibrillation

Larry Goldstein MD Peter Rothwell MD, PhD Section Editors: Identifying independent risk factors for stroke in patients with atrial fibrillation is important for 2 main reasons: it sheds light on stroke pathogenesis associated with this common cardiac dysrhythmia, and it allows stratification of stroke risk for individual patients. Both are keys to prevention of the unduly large cardioembolic brain infarcts that complicate atrial fibrillation. Among nonvalvular atrial fibrillation patients, the absolute risk of stroke averages 3% to 4% per year, but it varies 20-fold depending on patient age and other clinical features.1,2 Hence, stroke risk stratification allows the absolute benefits of prophylactic antithrombotic therapy to be estimated for individual patients.Since the initial analysis of the pooled control groups of 5 randomized clinical trials in 1994,3 several studies analyzing stroke risk factors in nonvalvular atrial fibrillation patients using multivariate analysis have yielded 4 consistent predictors: increasing age, hypertension/systolic blood pressure, diabetes, and prior embolism (Table 1).1 Prior stroke/TIA is the most powerful risk factor and is associated with high rates of stroke (>5% per year, averaging 10% per year) warranting anticoagulation, even in atrial fibrillation patients without other risk factors.1 Female sex has been less consistently linked to stroke risk, although independently predictive in 3 studies.1 Unexpectedly, heart failure has not …