A nomogram based on CHADS2 score for predicting atrial fibrillation recurrence after cryoballoon ablation

Background As reported, CHADS(2) scoring system moderately predicts the atrial fibrillation (AF) recurrence, a common event after cryoballoon ablation. We aimed to improve the diagnostic accuracy of the CHADS(2) score by adding several routine auxiliary detection indicators into the scoring system and constructing a CHADS(2) score-based nomogram to predict AF recurrence in patients with paroxysmal AF undergoing cryoballoon ablation. Methods Eighty-four patients with paroxysmal AF undergoing cryoballoon ablation were enrolled. Baseline characteristics were collected. The multivariable Cox proportional hazards model was used to identify the significantly related predictors of recurrence and to construct the nomogram whose performance was evaluated by the discrimination and calibration tests. Results Thirty-five patients developed AF recurrence after a mean follow up of 19.0 +/- 15.77 months. In the Cox multivariate model, CHADS(2) (>2) (hazard ratio [HR]: 2.38; 95% confidence interval [CI]: 1.14-4.98, p = .021) and albumin-to-globulin ratio (AGR) (HR: 2.49; 95% CI: 1.26-4.92, p < .008) were independent risk factors associated with AF recurrence. In addition to CHADS(2), AGR and red blood cell distribution width were used to construct the nomogram. As a result, the discrimination of the concordance index for the predictive model of AF recurrence was increased from 0.56 (95% CI: 0.494-0.632) to 0.712 (95% CI: 0.631-0.811). The 24-month one well matched the ideal 45 degrees line among the calibration plots for 6, 12, and 24 months' recurrence-free survival. Conclusion This novel easy-to-use CHADS(2) score-based nomogram may be used to predict AF recurrence for patient of paroxysmal AF undergoing cryoballoon ablation. Further external validation is still needed.