Abstract 15503: Biophysical Indicators of Acute Pulmonary Vein Isolation With a Novel Cryoballoon

Abstract

Introduction: Low nadir temperature (N T ) and long thaw times with cryoballoon ablation are associated with successful PVI. Recently, a cryo-system was designed to improve catheter stability during ablation via a balloon (CB, POLARx™, Boston Scientific) that maintains uniform pressure and size. The purpose of this study was to evaluate whether the CB biophysical parameters, including time to -40 o C (TT40), N T , time to thaw (iTT0), and time to 15 o C (iTT15), are associated with acute PVI success in paroxysmal AF patients. Methods: Ablation was delivered for 180s if isolation was achieved in ≤ 60s or 240s if isolation occurred after 60s. PVI was confirmed via entrance and exit block. Biophysical parameters were evaluated for 3 groups: block with 180s ablation, block with 240s ablation, and for unsuccessful initial treatments (gap veins). The diagnostic accuracy for predicting PVI was assessed using area under (AUC) the receiver operator characteristic (ROC) curve for ablations > 120s. Results: Forty-six consecutive de novo PVI procedures at 4 centers were analyzed (n=234 ablations). All PVs were isolated using the CB alone, with the vast majority within 60s. During freeze, TT40 and N T were significantly shorter and colder for isolated veins compared to gap veins (Table). During thaw, iTT0 and iTT15 were significantly longer for isolated veins compared to gap veins (Table). ROC analysis found iTT15 had the highest diagnostic accuracy for isolation (AUC: 0.85) followed by N T (AUC: 0.81), iTT0 (AUC: 0.77), and TT40 (AUC: 0.72). Optimal cutoff values for iTT15 and N T were 33.5s and -48 o C, which had positive predictive values for acute block of 96.6% and 93.5%. Conclusions: When using the novel CB, ablations reaching < -48 o C and having thaw times to 15 o C > 33.5s were predictive of acute block in PVI, providing guidance toward improved workflow and potential reduction in procedural time.