CHADS2 and CHA2DS2-VASc Scores for Prediction of Immediate and Late Stroke after Coronary Artery Bypass Graft Surgery

Background: We evaluated the value of CHADS(2) and CHA(2)DS(2)-VASc scores in predicting immediate and late stroke after coronary artery bypass grafting (CABG). Methods: One thousand two hundred twenty-six patients without preoperative atrial fibrillation underwent CABG and form the basis of this community-wide study. The main outcome endpoint of this study was any ischemic stroke with occurred immediately of late after CABG. Results: During a mean follow-up of 7.2 +/- 4.5 years, 114 patients (9.3%) suffered a stroke. Freedom from stroke at 30 days and at 1-, 5-, and 10-year follow-ups were 97.5%, 96.8%, 92.0%, and 87.7%, respectively. After excluding immediate postoperative strokes, the stroke rate per 100 patients per year was 1.36. Postoperative atrial fibrillation (relative risk [RR] 1.483; 95% confidence interval [CI] 1.009-2.179), age (RR 1.039; 95% CI 1.015-1.063), history of stroke (RR 2.951; 95% CI 1.797-4.846), vascular disease (RR 1.732; 95% CI 1.111-2.700), and previous CABG (RR 3.185; 95% CI 1.268-7.997) were independent predictors of any stroke. CHADS(2) (c-statistic 0.646) and CHA(2)DS(2)-VASc (c-statistic 0.668) predicted 30-day postoperative stroke (for increasing CHADS(2) risk classes: 1.6%, 1.6%, and 4.8%, respectively [P = .008]; for increasing CHA(2)DS(2)-VASc risk classes: 0.9%, 0.7%, and 3.3 % [P = .043]). Both risk scores predicted late stroke. At 10 years of follow-up, freedom from stroke in high-risk CHADS(2) was 80.4% and for high-risk CHA(2)DS(2)-VASc was 85.1%. These risk scoring methods predicted also any fatal stroke (c-statistics: CHADS(2) 0.641 [P = .040]; CHA(2)DS(2)-VASc 0.716 [P = .002]). Conclusions: A significant number of patients may suffer stroke late after CABG, and patients with a high risk of stroke can be identified by CHADS(2) and CHA(2)DS(2)-VASc scores independently from the presence of pre- or postoperative atrial fibrillation.