Relationship between CHA2DS2-VASc scores and ischemic stroke/cardiovascular events in Japanese patients with paroxysmal atrial fibrillation without receiving anticoagulant therapy

Abstract

The CHA(2)DS(2)-VASc score has been newly proposed for stratifying patients with nonvalvular atrial fibrillation (AF) according to the risk of ischemic stroke in the 2010 European Society of Cardiology guideline. However, there is little information about its usefulness for predicting long-term prognosis of cardiovascular events in Japanese patients with paroxysmal AF. This study retrospectively included 332 paroxysmal AF patients (224 men, mean age 65±13 years, mean follow-up period 53±35 months) without receiving anticoagulant therapy between June 1995 and August 2008 who were categorized into risk stratification on the basis of CHA(2)DS(2)-VASc score. The distribution of CHA(2)DS(2)-VASc scores was 0, 1, 2, 3, 4, 5, 6, and 7 points in 76 (23%), 60 (18%), 69 (21%), 69 (21%), 28 (8%), 23 (7%), 6 (2%), and 1 (0.3%) patients, respectively. The annual rates of symptomatic ischemic stroke were 0%, 0.60%, 0.95%, 1.96%, 5.45%, 9.06%, and 13.7% when the CHA(2)DS(2)-VASc score was 0, 1, 2, 3, 4, 5, and ≥6 points, respectively (p<0.001) and those of cardiovascular events including hospitalization for thromboembolism, heart failure and cardiovascular death were 0%, 1.43%, 1.50%, 2.52%, 10.14%, 12.85%, and 17.13% when the CHA(2)DS(2)-VASc score was 0, 1, 2, 3, 4, 5 and ≥6 points, respectively (p<0.001). Higher CHA(2)DS(2)-VASc scores were associated with greater annual rates of ischemic stroke and cardiovascular events. In a multivariate logistic regression analysis adjusted for the potentially confounding variables, the CHA(2)DS(2)-VASc score was associated with symptomatic ischemic stroke (odds ratio 7.051, 95% confidence interval 3.76-13.22, p<0.001) and cardiovascular events (odds ratio 3.448, 95% confidence interval 2.33-5.11, p<0.001). In Japanese patients with paroxysmal AF, the CHA(2)DS(2)-VASc score is a useful scheme for risk stratification of ischemic stroke and cardiovascular events.