Impact of the Individual Operator Experience and Learning Curve of a Novel Size Adjustable Cryoballoon

Cryoballoon ablation is less operator-dependent than radiofrequency ablation. Recently, size-adjustable cryoballoons (SA-CBs) have become available. We sought to analyze the individual baseline operator experience's impact on procedural results.

This multicenter observational study included atrial fibrillation (AF) patients who underwent pulmonary vein (PV) isolation using SA-CBs capable of 28-mm or 31-mm balloon sizes. Experienced (E-group) or less experienced (LE-group) operators were defined as experiencing > 100 or ≤ 100 cryoballoon procedures, respectively.

Among 510 patients (67 ± 11 years, 355 men, 325 paroxysmal AF [PAF]) who underwent an SA-CB ablation, 240 and 270 were in the E-group and LE-group, respectively. All cryoballoon parameters were similar between the groups, except for a significantly higher 31-mm balloon isolation rate in the E-group than LE-group, especially for right superior PVs. Cryoballoon-related phrenic nerve injury occurred in 34 (6.7%) patients and tended to be higher in the LE-group than E-group (8.1% vs. 5.0%, p = 0.16). The AF freedom was comparable between the groups for both PAF and non-PAF patients. A total of 36(7.1%) patients underwent re-do procedures at 5.2 ± 2.6 months post-index procedure. The PV reconnection rate was significantly higher in the LE-group than E-group (27.1% vs. 8.9%, p < 0.01), and this trend was more pronounced for right PVs than left PVs.

In AF ablation using SA-CBs, the overall procedural efficacy and safety were comparable between the E-group and LE-group. However, 100 CB procedures seemed to still be in the middle of a learning curve for selecting the balloon size and balloon position, especially for right PVs.