Results of the first randomised trial comparing pulsed field ablation (PFA) to thermal ablation for the treatment of paroxysmal atrial fibrillation (AF)—ADVENT—have shown that PFA is as safe and effective at 12 months.
Findings of the study, which involves Boston Scientific’s Farapulse PFA system, were presented by principal investigator Vivek Reddy (Icahn School of Medicine, New York, USA) during a Hot Line trial session at the European Society of Cardiology (ESC) congress (25–28 August, Amsterdam, The Netherlands) and published simultaneously in The New England Journal of Medicine (NEJM).
PFA utilises a controlled electric field to ablate and scar cardiac tissue through a process called irreversible electroporation (IRE). Preclinical and clinical studies have demonstrated that PFA seems to preferentially ablate the heart tissue, with minimal or no damage to surrounding structures such as the oesophagus and phrenic nerve, as well as no pulmonary vein stenosis, complications that may arise with thermal ablation.
The multicentre, prospective and randomised controlled ADVENT trial, enrolled 607 patients in the USA with paroxysmal AF who had previously been unsuccessfully treated with at least one anti-arrhythmic drug. Randomisation saw 305 patients undergo PFA and 302 patients conventional radiofrequency or cryoablation.
The trial’s primary efficacy endpoint was the success rate, defined as acute success and chronic success (one-year freedom from recurrent atrial arrhythmias, antiarrhythmic drug use, and cardioversion or repeat ablation). The success rate was 73.3% and 71.3% in the PFA and thermal groups, respectively, and met the prespecified criteria for non-inferiority.
The secondary efficacy endpoint was the same as the primary efficacy endpoint, but tested for superiority: this did not meet the criteria for superiority.
The primary safety endpoint was a composite of serious adverse events related to use of an ablation catheter or the procedure itself and occurring within seven days, as well as pulmonary vein stenosis or oesophageal fistula occurring at any time during the 12-month follow up. This endpoint occurred in 2.1% and 1.5% patients in the PFA and thermal groups, respectively, and met the prespecified criteria for non-inferiority.
The secondary safety endpoint was the change in pulmonary vein dimension (i.e., any stenosis or narrowing) from baseline to day 90. The reductions in vein cross-sectional area were 3.3% and 19.5% in the PFA and thermal groups, respectively, which met the prespecified criteria for superiority of PFA.
“The ADVENT trial showed that PFA is as effective and safe as conventional thermal ablation to treat paroxysmal AF,” said Reddy. “Procedure times were faster for PFA than thermal ablation, but there was more X-ray exposure with PFA.”
The Farapulse PFA system received CE Mark in 2021 and findings of the ADVENT study are intended to support US Food and Drug Administration (FDA) approval of the catheter in the USA.
“These data underscore the superior procedural efficiency of this novel technology, and real-world use continues to yield strong safety and efficacy outcomes,” said Kenneth Stein, senior vice president and global chief medical officer at Boston Scientific. “The performance of the Farapulse PFA system in this trial is an encouraging sign of the potential utilisation of the device in the USA and we look forward to further studying the system for the treatment of patients with persistent AF in the ADVANTAGE AF clinical trial, which began enrolment earlier this year.”