Duration of Applications Affects the Long-Term Efficacy of Cryoballoon Ablation Pulmonary Veins

Aim      To evaluate the effect of cryo-exposure duration and the use of the Achieve circular mapping catheter on efficacy of cryoballoon ablation (CBA).Material and methods  CBA of pulmonary vein ostia (PVO) is a major method for heart rhythm control in patients with atrial fibrillation (AF). Since the inception, the PVO CBA method has evolved; the recommended application time was changed, and the Achieve circular catheter appeared. We performed a retrospective analysis of PVO CBA administered to patients with AF in the I.V. Davydovsky Municipal Clinical Hospital from 2017 through 2019. The study included 100 patients with available clinical and demographic characteristics and remote results of the intervention. Three patient groups were analyzed based on differences in surgical techniques: group 1, Guidewire / 240 (n=31) with the cryoballoon placing on a guidewire and PVO exposure duration of 240 s; group 2, Guidewire / 180 (n=26) with the cryoballoon placing on a guidewire and PVO exposure duration of 180 s; and group 3, Achieve / 180 (n=43) with the cryoballoon placing on the mapping catheter Achieve and PVO exposure duration of 180 с. The follow-up period was 33.2±4.5, 15.2±6.1, and 12.2±4.1 months in the Guidewire / 240, Guidewire / 180, and Achieve / 180 groups, respectively. The intervention was considered effective when there was no relapse at the time of interview. A relapse of AF was determined as one or more paroxysms recorded on electrocardiogram (ECG) or during 24-h ECG monitoring; the "blind period" (first 3 months after the procedure) was excluded from the follow-up. Safety evaluation included clinically significant complications, such as phrenic nerve damage, hemopericardium, gastroparesis, hemoptysis, acute cerebrovascular disease, and formation of atrio-esophageal fistula. Effects of independent factors were determined with binary logistic regression.Results In the Guidewire / 240 group, efficacy of PVO CBA for the maximum follow-up period was 74.4%, which was significantly different from the value for the Guidewire / 180 group (57.7 %, р=0.015). At the same time, the difference between the Guidewire / 240 and Achieve / 180 groups was statistically non-significant for a comparable follow-up period (р=0.144). Clinically significant complications were absent in all 3 groups. The independent factors that significantly increased the PVO CBA efficacy were the cryo-exposure duration of 240 s compared to 180 s (р= 0.018) and the use of the Achieve catheter (р=0.014).Conclusion      Decreasing the cryo-exposure duration to less than 240 s is impractical (in absence of Achieve mapping catheter) since it impairs the long-term efficacy of PVO CBA and does not influence the risk of complications.