Atrial fibrillation ablation with the second generation cryoballoon: Multicenter propensity score matched comparison between freezing strategies. (15th February 2018) - Ströker, Erwin
Abstract: Background: Second generation cryoballoon (CB-A) ablation is highly effective in achieving pulmonary vein (PV) isolation and freedom from atrial fibrillation (AF). However, the ideal freezing strategy is still under debate. Our objective was to investigate the efficacy and outcome between different freezing strategies used with the CB-A in a multicenter, matched population. Methods: From a total cohort of 1018 patients having undergone CB-A ablation for drug-refractory AF, 673 patients with follow-up ≥ 6 months were included and stratified according to the applied freezing strategy: bonus freeze (BF) versus single freeze (SF). Final population of 256 BF patients was compared with 256 propensity-score matched SF patients. Results: BF strategy consisted of 3 different protocols: 3 cycles of 180 s; 2 cycles of 240 s; and cycles of 240 s followed by 180 s in 99/256 (39%); 42/256 (16%); and 115/256 (45%) patients, respectively. SF approach included cycles of 240 s in 23/256 (9%), and 180 s in 233/256 (91%) patients. Electrical isolation could be achieved in all PVs by both protocols, with shorter procedure and fluoroscopy times in the SF group (mean 106 vs 65 min, and 18 vs 14 min, respectively, P < 0.001). Phrenic nerve palsy persisted after discharge in a total of 11 patients (2.1%): 4 (1.6%) in the BF group vs 7 (2.7%) in the SF group, P = 0.5. AF-free survival was similar between the 2 groups during follow-up (mean 18 ± 10 months) (log rank, P = 0.6). Conclusions: CB-A ablation showed equal efficacy and outcome between SF and BF strategy. Highlights: Matched comparison between freezing strategies used for atrial fibrillation ablation with the second generation cryoballoon Bonus freeze strategy was compared with a single freeze approach Both groups provide 100% acute pulmonary vein isolation and an equal distribution of procedure related complications Shorter procedure time and fluoroscopy exposure was observed in the single freeze group Similar clinical outcome was observed between both strategies