Cryoballoon Best Practices II: Practical guide to procedural monitoring and dosing during atrial fibrillation ablation from the perspective of experienced users

Abstract

Since the evaluation of the cryoballoon in the Sustained Treatment Of Paroxysmal Atrial Fibrillation trial, more than 350,000 patients with atrial fibrillation have been treated. Several studies have reported improved outcomes using the second-generation cryoballoon, and recent publications have evaluated modifications, refinements, and improvements in procedural techniques. Here, peer-reviewed articles published since the first cryoballoon best practices review were summarized against the technical practices of physicians with a high level of experience with the cryoballoon (average ≥6 years of experience in ≥900 cases). This summary includes a comprehensive literature review along with practical usage guidance from physicians using the cryoballoon to facilitate safe, efficient, and effective outcomes for patients with atrial fibrillation.

Relationship between time‐to‐isolation and freeze duration: Computational modeling of dosing for Arctic Front Advance and Arctic Front Advance Pro cryoballoons

“…In our study, the three‐dimensional computational model represents the ablation sequence of a typical cryoballoon application from the 28‐mm AFA or AFA Pro. The clinical applications and methods of CBA have previously been well described . In brief, the inflated balloon is positioned in the LA to engage the antral cardiac tissue surface of the PV.…”

“…This endothermic process removes heat energy from cardiac tissue in contact with the distal hemisphere of the balloon surface, which results in the local creation of both intracellular and extracellular ice. The resulting biophysical process of cellular destruction concludes with a demarcated lesion or scar tissue and electrical isolation of the PV …”

“…Consequently, studies were initiated to redefine AFA dosing parameters (Figure and Table ), including (a) examining the requirement for multiple cryofreeze applications (including the bonus freeze and freeze‐thaw‐refreeze applications); (b) evaluating reductions in freeze duration; and/or (c) investigating intraprocedural data with regard to balloon characteristics (eg, balloon nadir temperature, acute time‐to‐isolation [TTI], and balloon thaw time) that could be used to inform real‐time, individualized dosing . Through these studies, TTI < 60 seconds has been identified as a strong intraprocedural predictor of CBA longer‐term PVI durability . When observed, real‐time TTI of pulmonary vein (PV) signals provide a measurable parameter of acute cardiac tissue damage that can predict a durable longer‐term freedom from AF recurrence …”

Pulmonary veins anatomical determinants of cooling kinetics during second‐generation cryoballoon ablation

“…Cooling kinetics data were collected for every procedure and included time to reach −40°C; temperature at 60 seconds; TTI; NT, and rewarming time to 0°C (TT0). We defined satisfactory every CbA application when an NT lower than −48°C could be reached 4 . Left common ostium cryoablation and applications interrupted early due to PNI were excluded from the analysis.…”

Delineating the physiology of cryoballoon ablation

“…The continuously evolving target of cryoballoon dosing results in great variation in real‐world practice; therefore, the identification and utilization of a physiological end‐point is vital. Ablation temperature, acute loss of pulmonary vein (PV) signal, and length of postablation thaw time have all been suggested . Avital et al have proposed the use of impedance rise and total impedance as a predictor of complete acute PV isolation.…”