Real-World Safety Profile of Atrial Fibrillation Ablation Using a Second-Generation Cryoballoon in Japan: Insight From a Large Multicenter Observational Study.

Objectives: This study sought to investigate the incidence and characteristics of the real-world safety profile of second-generation cryoballoon ablation (2nd-CBA) in Japan.

Background: Pulmonary vein isolation using second-generation cryoballoons is an accepted atrial fibrillation ablation strategy.

Methods: This multicenter observational study included 4,173 patients with atrial fibrillation (3,807 paroxysmal) who underwent a 2nd-CBA in 18 participating centers. The baseline data and details of all procedure-related complications within 3 months post-procedure in consecutive patients from the first case at each center were retrospectively collected.

Results: Adjunctive ablation after the pulmonary vein isolation was performed in 2,745 (65.8%) patients. Complications associated with the entire procedure were observed in 206 (4.9%) total patients, and in the multivariate analysis, the age (odds ratio: 1.015; 95% confidence interval: 1.001 to 1.030; p = 0.035) and study period were predictors. Air embolisms manifesting as ST-segment elevation and cardiac tamponade requiring drainage occurred in 63 (1.5%) and 15 (0.36%) patients, respectively. Six (0.14%) patients had strokes/transient ischemic attacks, among whom 5 underwent ablation under an interrupted anticoagulation regimen. No atrioesophageal fistulae occurred; however, 10 (0.24%) patients had symptomatic gastric hypomotility. Esophageal temperature monitoring did not reduce the incidence, and the incidence was significantly higher in patients with adjunctive posterior wall isolations or mitral isthmus ablation than those without (p = 0.004). Phrenic nerve injury occurred during the 2nd-CBA in 58 (1.4%) patients; however, all were asymptomatic and recovered within 13 months. One patient died of aspiration pneumonia.

Conclusions: This study had a high safety profile of 2nd-CBA despite including the early experience and high rate of adjunctive ablation. Care should be taken for air embolisms during 2nd-CBA.