Difference in tissue temperature change between two cryoballoons

Abstract

Background Cryoballoon ablation, especially Arctic Front Advance Pro (AFA-Pro) (Medtronic, Minneapolis, Minnesota, USA), has been widely recognised as a standard approach to atrial fibrillation (AF). Recently, Boston Scientific has released a novel cryoballoon system (POLARx). Despite comparable acute clinical outcomes of these two cryoballoons, the recent study reported a higher complication rate, especially for phrenic nerve palsy, with POLARx. However, their impact on biological tissue remains unclear.Objective The purpose of our study is to evaluate temperature change of biological tissue during cryoablation of each cryoballoon using a porcine experimental model.Method A tissue-based pulmonary vein model was constructed from porcine myocardial tissue and placed on a stage designed to simulate pulmonary vein anatomy and venous flow. Controlled cryoablations of AFA-Pro and POLARx were performed in this model to evaluate the tissue temperature. A temperature sensor was set behind the muscle and cryoballoon ablation was performed after confirming the occlusion of pulmonary vein with cryoballoon.Results The mean tissue nadir temperature during cryoablation with AFA-Pro was −41.5°C±4.9°C, while the mean tissue nadir temperature during cryoablation with POLARx was −58.4°C±5.9°C (p<0.001). The mean balloon nadir temperature during cryoablation with AFA-Pro was −54.6°C±2.6°C and the mean balloon nadir temperature during cryoablation with POLARx was −64.7°C±3.8°C (p<0.001).Conclusion POLARx could freeze the biological tissue more strongly than AFA-Pro.