Use of Preoperative CHA ₂ DS ₂ ‐ VAS c Score to Predict the Risk of Atrial Fibrillation After Cardiothoracic Surgery: A Nested Case–Control Study from the Atrial Fibrillation Suppression Trials ( AFIST ) I, II, and III

STUDY OBJECTIVE: To evaluate whether the preoperative CHA2 DS2 -VASc score predicts the risk of atrial fibrillation (AF) after cardiothoracic surgery (CTS). DESIGN: Retrospective, nested case-control study. PATIENTS: A total of 560 patients undergoing coronary artery bypass grafting and/or valvular surgery from the Atrial Fibrillation Suppression Trials I, II, and III. MEASUREMENTS AND MAIN RESULTS: All variables showing a univariate association (p≤0.20) with AF occurrence were entered into a backward stepwise multivariate logistic regression analysis to control for potential confounders and to calculate adjusted odds ratios (AORs) with 95% confidence intervals (CIs). The population was age 67.8 ± 8.6 (mean ± SD) years and 77.1% male, with CHA2 DS2 -VASc scores of 0-1 (low) in 34 patients (6.1%), 2-3 (medium) in 261 patients (46.6%), and more than 3 (high) in 265 patients (47.3%). Post-CTS AF occurred in 177 patients (31.6%), with 27%, 23%, and 41% in the low-, medium-, and high-CHA2 DS2 -VASc score groups, respectively. The high-score group had a 2.3-fold increased odds of developing AF versus the medium-score group (p<0.0001). The differences between the high- and medium-score groups when each group was compared with the low-score group were not statistically significant. On the multivariate logistic regression analysis, CHA2 DS2 -VASc score was associated with development of AF (AOR 1.20, 95% CI 1.06-1.36). CONCLUSION: Increasing CHA2 DS2 -VASc score was an independent predictor for the development of post-CTS AF, with patients in the high-score group having the highest overall incidence.