Low Recurrence Rate Cited for Persistent-AF Ablation in PRECEPT Study

May 11, 2020

Catheter ablation, a mainstay for paroxysmal atrial fibrillation (AF), is also often performed in patients with persistent AF, although based on less supporting evidence. There isn't yet a catheter approved by the US Food and Drug Administration for use in persistent AF.

A newly reported study, however, adds to the evidence base for ablation of persistent AF as it becomes part of a bid for one catheter's approval specifically for that indication.

In the prospective but single-group PRECEPT study, patients with symptomatic, drug-refractory persistent AF who underwent ablation procedures using a Biosense Webster porous-tip, contact-force-sensing catheter showed clinical effectiveness at least comparable to literature-based numbers, and a low adverse-event rate that was within accepted benchmarks even for ablation of paroxysmal AF, researchers say.

About 62% of the patients remained free of atrial arrhythmia, repeat ablations, or new antiarrhythmic drug use over the 15-month follow-up, while the rate of adverse events was less than 4%. The group also showed far less need for cardioversion or antiarrhythmic drug therapy after the procedure than before, observed Moussa Mansour, MD, Massachusetts General Hospital, Boston.

Mansour presented the results of PRECEPT online May 8 as one of the Heart Rhythm Society 2020 Scientific Sessions virtual presentations. He is also lead author on the study's same-day publication in JACC: Clinical Electrophysiology.

The estimated rate of freedom from repeat ablation was about 89% at 12 months and 86% at 15 months, Monsour told theheart.org | Medscape Cardiology.

"That's a huge reduction" compared with published rates in the United States for ablation of paroxysmal and persistent AF combined, about 17% at 12 months, he said, acknowledging that it's just an impression given the lack of studies directly comparing different ablation catheters in persistent AF.

Operators in PRECEPT used the Thermocool SmartTouch (Biosense Webster) with contact-force sensing and proprietary lesion-targeting software.

"The safety and efficacy profiles of this catheter are indeed encouraging," Sana M. Al-Khatib, MD, MHS, Duke University Medical Center, Durham, North Carolina, said as an invited discussant after the formal PRECEPT presentation.

"It is important to keep in mind that procedures in this study were performed by experienced operators and the results may not extrapolate to less experienced operators," Al-Khatib said.

"It would be good to get more data on this catheter, perhaps in real-world settings, to see if these results can be replicated by other groups," she said.

Only one type of ablation catheter from one company was used, "so the results really only pertain to these operators using this catheter," agreed another discussant, Eric N. Prystowsky, MD, St. Vincent Hospital and Health Center, Indianapolis.

"So I think the true test of this catheter is to compare it to something else, and then we'll find out the efficacy. But as far as safety, I think the authors have shown me it's fine," Prystowsky said.

On the other hand, "the study involved a large number of patients, with procedures performed across 27 centers, adding to the strength of its generalizability," proposes an editorial from Edward P. Gerstenfeld, MD, and Joshua D. Moss, MD, University of California, San Francisco, accompanying the PRECEPT publication.

The study "demonstrates the necessary safety and effectiveness to likely gain FDA approval" for the catheter for the indication of persistent AF, write Gerstenfeld and Moss.

As Mansour reported in his virtual presentation, the analysis included 881 patients in Canada and the United States with symptoms from persistent AF, recognized from at least a week to 1 year, who were unresponsive to or intolerant of at least one class I/III antiarrhythmic agent. Patients with excessive left atrial dilation or left ventricular ejection fractions less than 40% were excluded.

All patients underwent AF ablation by pulmonary vein isolation (PVI), in 44.5% of cases also involving nonpulmonary-vein left-atrial targets at the operators' discretion. The safety and effectiveness cohorts consisted of 348 and 333 patients, respectively.

The two successive 3-month blanking periods were to allow for any postablation medical therapy and a subsequent opportunity for repeat ablation as needed. The repeat ablation rate in PRECEPT was 5.7% during and 7.8% after the blanking period, for an average of 1.1 repeat ablations per patient throughout the study, Mansour reported.

After the blanking periods, the incidence of the primary safety end point, adverse events striking within 7 days of the initial or any repeat ablation procedures, was 3.8% at 15 months, soundly beating the prespecified performance goal of 16%.

The 14 adverse events seen in 13 patients included five cases of cardiac tamponade, three of vascular access bleeding, and two neurovascular events. There were no procedure-related deaths or atrial esophageal fistulas.

The 15-month rate of the primary effectiveness success end point, defined as freedom from documented recurrent AF, atrial tachycardia, or atrial flutter, was 61.7%, surpassing the prospective performance benchmark of 40%, Mansour said.

The corresponding rate of clinical success, defined as freedom from documented recurrent symptomatic AF or other atrial arrhythmia, was 80.4%. About 84% were free from cardiovascular hospitalization.

In post hoc analyses, there was an 82.7% reduction in need for cardioversion and 74.5% drop in use of antiarrhythmic agents — from virtually all patients to only about one-fourth of them — from baseline to 15 months (< .001 for both end points).

The results "support prognostic expectations that we currently give our patients with persistent AF," says the editorial. "The key benefit from ablation is symptomatic improvement, and we can usually achieve sinus rhythm, but it may take more than one procedure and continued antiarrhythmic drug therapy to get there."

It also may often take more extensive ablation than possible with PVI alone, proposed Mansour, who says the field should get used to the idea that persistent AF may frequently require additional ablations beyond just the pulmonary vein area for better success. That was the case in nearly half of cases in PRECEPT, and is "one of the most important messages from this study."

The idea implies that balloon-based ablation catheters that are generally limited to PVI procedures will be less successful in persistent AF than catheters that can also ablate outside the pulmonary vein area, Mansour said.

"The underlying assumption of a one-size-fit-all concept for most persistent-AF ablation studies deserves re-evaluation and consideration," Mansour and his colleagues say in their published report.

PRECEPT was is funded by Biosense Webster. Mansour discloses serving as a consultant for Biosense Webster, Abbott, Medtronic, Boston Scientific, Janssen, Philips, Novartis, and Sentre Heart; receiving research grants from Biosense Webster, Abbott, Boston Scientific, Medtronic, Pfizer, and Boehringer Ingelheim; and holding equity interest in EPD Solutions, NewPace, and Affera. Al-Khatib discloses receiving honoraria or speaking or consulting fees from Milestone Pharmaceuticals and Medtronic. Prystowsky discloses receiving honoraria or speaking or consulting fees from CardioNet and Medtronic and holding stock or stock options for Stereotaxis. Gerstenfeld discloses receiving lecture honoraria and research grants from Biosense-Webster. Moss had no disclosures.

JACC Clin Electrophysiol. Published online May 8, 2020. Full text, Editorial

Heart Rhythm Society (HRS) 2020 Scientific Sessions. Presented May 8, 2020.

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