B-PO02-105 OCCLUSION GRADE OF PULMONARY VEIN IN PATIENTS WITH ATRIAL FIBRILLATION AND COOLING CHARACTERISTICS WHEN A NOVEL CRYOABLATION TECHNOLOGY IS USED: PRELIMINARY EXPERIENCE FROM AN ITALIAN REGISTRY

Abstract

Adequate contact between the tissue and energy source affects the efficacy of cryoablation in pulmonary vein isolation (PVI). However, the effect of PV occlusion grade on cooling parameters using a novel cryoballoon technology (POLARx) has not yet been reported. to evaluate how complete and incomplete PV occlusion translates into cooling parameters when using a new cryo-technology. Consecutive patients (pts) undergoing AF ablation from the CHARISMA registry at 5 centers were included. Leak(s) of contrast into the left atrium indicates incomplete occlusion. Occlusion grade (OG) was scored as COG for complete occlusion and IOG for incomplete occlusion. Protocol-directed cryoablation was delivered for 180 sec or 240 sec according to the operator’s preference for isolation achieved in ≤60 sec or 240 sec if isolation occurred >60 sec or when time to isolation (TTI) was not available. The ablation endpoint was PV isolation as assessed by entrance and exit block. Two-hundred and one cryoapplications from 40 pts with OG information (96.6% of all 208 cryoapplications) were analyzed. PVI was achieved with cryoablation in all pts. The mean number of cryoapplications per pt was 5.2±1.6, with 18 (45%) pts treated with a single freeze to each of the PVs. The mean nadir temperature was -55.9 ± 6.6 °C. In the majority of the cryoapplications, the occlusion was scored as complete (COG=137, 68.2%) spanning from 73.1% on LIPV, 71.9% in LSPV, 67.4% and 58.7% for RSPV and RIPV, respectively, whereas incomplete occlusions were less frequent (IOG=64, 31.8%). Nadir temperature was significantly colder in the COG group compared to IOG (-57.7±5.5 °C for COG vs -51.8±7.1 °C for IOG, p<0.0001) whereas both thaw time to 0°C and deflation time from 0°C to 20°C were significantly longer (COG vs IOG: 20.6±6.3 vs 16.7±6.2 sec for thaw time, p<0.0001;26.3±13.5 vs 19.8±9.0 sec for deflation time, p=0.0041). No complications were observed at 30 days post-procedure. In our first multicentric experience with a novel technology, the cryoballoon ablation was safe and effective. Incomplete PV occlusion was associated with less satisfactory cooling parameters.