Long-term success rates of a stable, low pressure cryo balloon for the treatment of paroxysmal atrial fibrillation - results of the prospective, international, multicenter POLAR-ICE study

Abstract

Abstract Background/Introduction Pulmonary vein isolation (PVI) using a cryo balloon is well-established for the treatment of paroxysmal atrial fibrillation (PAF). Compared to other available technologies, the usage of a stable, low pressure cryo balloon (POLARx, Boston Scientific) has demonstrated lower nadir temperatures and longer thawing times. However, long term efficacy and safety still needs to be proven. Purpose The aim of the POLAR-ICE Study was to evaluate long-term efficacy and safety outcome of cryo balloon ablation in patients with paroxysmal atrial fibrillation. Methods POLAR ICE, a prospective, non-randomized, international, multicenter study, enrolled 399 patients across 19 centers, between Aug 2020 and May 2021. Patients with paroxysmal atrial fibrillation undergoing de novo PVI were included into the study. During the index procedure, procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, balloon nadir temperature, and occlusion grade were recorded. Procedural success was defined as successful isolation of each vein proven by entrance block. Follow up visits were at 3, 6, and 12 months. Recurrence is defined as any documented (ECG/Holter) episode of atrial fibrillation / atrial tachycardia longer than 30sec. after a blanking period of 3 months. Results 399 patients (mean age 61 years, 36% female) were included into the study. After 12 months, freedom from any arrhythmia was 83.5% and freedom from atrial fibrillation 88.1% (Figure 1). Procedure/ablation related Serious adverse events occurred in 8.7% of patients, and included access complications (2.6%), cardiac tamponade (0.5%), air embolism (0.3%), AV block (0.3%), effusion (0.3%) phrenic nerve palsy (0.3%), stroke (0.3%), transient ischemic attack (0.3%). Redo procedures have been conducted in 19 patients. In 14/19 pts reconnection of at least one PV could be identified (RSPV n=8, RIPV n=12, LSPV n=9, LIPV n=11). Freedom from any arrhythmia was associated with lower nadir temperature (p=0.008) and longer time to thaw (p=0.05) during the index procedure. Conclusions In this prospective, non-randomized, international, multicenter study, isolation of the pulmonary veins using a stable, low pressure cryo balloon was highly effective and safe in patients treated for paroxysmal atrial fibrillation. Lower nadir temperatures and a longer thawing time were predictors of clinical success.