Usefulness of serum uric acid level to predict atrial fibrillation recurrence after cryoballoon-based catheter ablation

AIMS: Catheter-based atrial fibrillation (AF) ablation has become an important therapeutic option in AF patients. Although there has been significant improvent in procedural success, post-procedural AF recurrences are continuing to be a major clinical problem. To the best of our knowledge, the impact of pre-procedural serum uric acid (SUA) level, as a pro-oxidant and pro-inflammatory marker, on AF recurrence following cryoballoon-based AF ablation has never been studied before. The objective of this study was to establish whether there is a relationship between levels of SUA and recurrence of paroxysmal AF after catheter ablation. METHODS AND RESULTS: A total of 363 patients (mean age 53.5 ± 11.2 years, 52.6% male) with symptomatic paroxysmal AF underwent initial cryoablation procedure. Patients were categorized into quartiles on the basis of their pre-procedural SUA assays and follow-up, and the Kaplan-Meier estimation with a log-rank test was used for the analysis of the influence of SUA on the recurrence of AF. Post-ablation blanking period was observed for 3 months. At a mean follow-up of 19.2 ± 6.1 months, 68 patients (18.7%) had developed AF recurrence. Atrial fibrillation recurrence rates from the lowest to the highest SUA quartiles were 2.9, 7.4, 11.8, and 77.9%, respectively (P < 0.001). On multivariate Cox regression analysis, pre-ablation SUA level (HR: 1.96, 95% CI: 1.49-2.59, P < 0.001), left atrial diameter (HR: 1.11, 95% CI: 1.04-1.19, P = 0.002) and early AF recurrence (HR: 4.34, 95% CI: 1.9-9.95, P = 0.001) were independent predictors of AF recurrence after cryoablation. Using a cut-off level of 6.37, the pre-ablation SUA level predicted AF recurrence during follow-up with a sensitivity of 85.7% and a specificity of 83.7%. CONCLUSION: In this prospective study of patients with paroxysmal AF undergoing cryoablation, increased pre-ablation SUA levels were associated with a higher rate of AF recurrence. Our results support the role of a pre-ablation pro-inflammatory and pro-oxidant environment in the development of AF recurrence after ablation therapy but suggest that other factors are also important.