Additional ablation in case of ostial level pulmonary vein isolation or spared carina does not improve 1-year outcome after cryoballoon ablation. Results of the NOCA-AF study

Abstract Background Pulmonary vein (PV) isolation using antral-level lesions has shown superior efficacy over smaller ostial lesions in treating atrial fibrillation (AF). However, with the 28-mm fixed-diameter cryoballoon (CB) and a vein-specific ablation approach, ostial-level isolation or carina-sparing occurs in many veins potentially negatively impacting outcome. This limitation can be mitigated through segmental non-occlusive cryoballoon ablations (NOCA), which extend lesion sets to the antral level or target spared carina regions. Purpose To assess the feasibility and effectiveness of NOCA in obtaining antral level PVI level and carina ablation. To study in a prospective randomized manner aiming to determine whether PVI plus individualized segmental NOCA in case of ostial level PVI or ablation sparing the carina improves outcome in patients with AF. Methods One hundred symptomatic drug refractory AF patients (Age 66±10years, 40 Females) were randomly assigned in a 1:1 ratio to Achieve catheter–guided cyoballoon ablation (CBA) with EnSite left atrium (LA) voltage maps pre- and post-CBA (Control group; N=50) and Achieve catheter–guided CBA with EnSite voltage maps pre- and post-CBA and subsequent individualized segmental NOCA of 120 seconds (Study group; N=50) if the post-CBA voltage map showed an ostial level PVI (defined as an ablated PV region (<0,5mV) until (but not surpassing) the level of the LA-PV junction) or ablation sparing the carina. Validation of the effectiveness of segmental NOCA in reaching antral level PVI or carina ablation was assessed by a voltage re-map. The primary study end point was defined as recurrent AF or atrial tachycardia lasting >30sec over 12 months of observation, with 24u Holter monitoring performed at 6 and 12 months. Results Clinical and freezing characteristics were similar between groups except more female patients (26 (52%) vs. 14 (28%), P=0.014) and more patients with diabetes (8 (16%) vs. 1(2%), P=0.014) in the study group. Thirty eight of the 50 patients in the Study group were treated with segmental NOCA with respectively 1, 2, 3 and 4 segmental NOCA administered in 17, 8, 6 and 7 patients. Effectiveness of NOCA could be demonstrated by voltage remapping in all 38 patients. The primary study end point did not significantly differ in between groups occurring in 12 (24%) Study patients and in 8 (16%) patients in the Control group, (P 0.407). On-treatment analysis comparing patients treated with NOCA (38) to patients non receiving NOCA (62) was also not different (32/38 (84%) versus 48/62(77%), P 0.362). Procedure and Fluoroscopy time were similar: 74±18min vs. 69±16min (P 0.09) and 10±5min vs. 12±6min (P 0.174) in the NOCA and Control group respectively. Conclusions Although highly efficient in obtaining antral level PVI or carina ablation, a strategy to incorporate segmental non-occlusive cryoablations on an individualized basis on top of routine CBA did not result in a better 1-year clinical outcome.