Clinical utility of CHADS₂ and CHA₂DS ₂-VASc scoring systems for predicting postoperative atrial fibrillation after cardiac surgery

Objectives: The presence of postoperative atrial fibrillation predicts a higher short- and long-term mortality rates; however, no scoring system has been used to discriminate patients at high risk for this complication. The aim of this study was to investigate whether the CHADS₂ and CHA ₂DS₂-VASc scores are useful risk assessment tools for new-onset atrial fibrillation after cardiac surgery. Methods: A total of 277 consecutive patients who underwent cardiac surgery were prospectively included in this risk stratification study. We calculated the CHADS₂ and CHA₂DS₂-VASc scores from the data collected. The primary end point was the development of postoperative atrial fibrillation within 30 days after cardiac surgery. Results: Eighty-four (30%) of the patients had postoperative atrial fibrillation at a median of 2 days (range, 0-27 days) after cardiac surgery. The CHADS₂ and CHA₂DS₂-VASc scores were significant predictors of postoperative atrial fibrillation in separate multivariate regression analyses. The Kaplan-Meier analysis obtained a higher postoperative atrial fibrillation rate when based on the CHADS ₂ and CHA₂DS₂-VASc scores of at least 2 than when based on scores less than 2 (both log rank, P 2DS₂-VASc scores could be used to further stratify the patients with CHADS₂ scores of 0 or 1 into 2 groups with different postoperative atrial fibrillation rates at a cutoff value of 2 (12% vs 32%; P =.01). Conclusions: CHADS₂ and CHA₂DS₂-VASc scores were predictive of postoperative atrial fibrillation after cardiac surgery and may be helpful for identifying high-risk patients.