High incidence of steam pop formation with therapy cool flex rf ablation catheter

Abstract

Background: Open irrigation catheters have the advantage of delivering greater power without increasing the temperature of the catheter tip, which enables deeper and wider lesions without the formation of coagulum on catheters. The ThermoCool Celsius® radiofrequency (RF) ablation catheter is the most widely used open irrigated RF ablation catheter, while the Therapy™ Cool Flex™ is the first fully irrigated flexible tip catheter that has a laser cut electrode and conforms to tissue. We sought to evaluate the safety profile of the Cool Flex catheter during RF ablation as compared to the ThermoCool catheter. Methods: Patients who underwent RF ablation at the American University of Beirut Medical Center between July 2012 and October 2013 were retrospectively identified, and stratified depending on the type of catheter used during the procedure: Group 1, Therapy™ Cool Flex™ RF ablation catheter; and Group 2, ThermoCool Celsius® RF ablation catheter. The primary endpoints were: 1) Steam pop (detected by audible cue); and 2) pericardial effusion by intracardiac and transthoracic echocardiograms; and secondary endpoint was a composite of failed ablation, steam pop, effusion, tamponade or death. The study was approved by the Institutional Review Board and was set in according with the Declaration of Helsinki. Results: A total of 54 consecutive patients underwent RF ablation: 12 patients with the Therapy™ Cool Flex™ catheter (Group 1) and 42 patients with ThermoCool Celsius® catheter (Group 2). Patients in Group 1 were significantly older, had more coronary artery disease and heart failure and more likely to be on anticoagulation than those in Group 2. There was a significantly greater incidence of steam pop in the Therapy™ Cool Flex™ group (33.3% vs. 2.4%, p < 0.05) and more pericardial effusion (16.6% vs. 0%, p < 0.05) including one tamponade case that could not be resuscitated. After multivariate adjustment, Cool Flex catheter use was significantly associated with worse outcome (odds ratio 33.3 [3.30-336], p = 0.003). Conclusion: In patients undergoing irrigated RF ablation, the Therapy™ Cool Flex™ RF ablation catheter was significantly associated with an increase in the risk of steam sop formation and pericardial effusion as compared to the ThermoCool catheter group. Careful interpretation of the results is warranted given the small sample size and increased comorbidities in the Therapy™ Cool Flex™ group.A larger study is needed to confirm these results and further assess the safety of the catheter. © 2019 Lebanese Order of Physicians. All rights reserved.