‘Hot,’ ‘Cold’ Ablation Prove Equal in Afib – MedPage Today
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Cryoballoon ablation did not prove less effective than radiofrequency ablation among patients with drug-refractory paroxysmal atrial fibrillation, researchers reported here.
Among 762 patients, the primary efficacy endpoint was met by 138 patients in the pulmonary-vein isolation cryoballoon group and 143 in the pulmonary-vein isolation radiofrequency group at 1 year (34.6% and 35.9%, respectively 1 year Kaplan-Meier event rates, hazard ratio, 0.96, 95% CI 0.76-1.22, P<0.001 for non-inferiority), said Karl-Heinz Kuck, MD, of Asklepios Klinik St. Georg in Hamburg, Germany, and colleagues.
In addition, the primary safety endpoint occurred in 40 patients in the cryoballoon group and in 51 patients (P=0.24), they reported in the New England Journal of Medicine.
“I would recommend cryoballoon ablation, especially for clinicians who are less experienced with catheter ablation,” Kuck told MedPage Today at the American College of Cardiology annual meeting, where the results were simultaneously presented. “This is a faster, simpler and safer procedure than radiofrequency ablation.”
In the FIRE AND ICE study, the researchers recruited 750 patients in a modified intention-to-treat protocol, assigning 374 patients with atrial fibrillation to cryoballoon ablation and 376 to radiofrequency ablation. The mean duration of follow-up was 1.5 years.
“Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation,” Kuck said. “Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology.”
The goal of the study was to determine if cryoballoon ablation was non-inferior to radiofrequency ablation in symptomatic patients with drug-refractory (class I or class III anti-arrhythmic drugs or beta blockers) paroxysmal atrial fibrillation. The primary efficacy endpoint in a time-to-event analysis was the first documented clinical failure — recurrence of atrial fibrillation, occurrence of atrial flutter or atrial tachycardia, use of anti-arrhythmic drugs, or repeat ablation following a 90-day period after the index ablation. The primary safety endpoint was a composite of death, cerebrovascular events, or serious treatment-related adverse events.
The trial was conducted in 16 centers in eight countries. Enrollment of patients started in January 2012 and was completed in January 2015.
After the index ablation procedure, in-office visits were scheduled at 3, 6, and 12 months and every 6 months thereafter. At each visit, a medical history was obtained, a physical examination was performed, and a 12-lead electrocardiogram and a 24-hour Holter monitor recording were obtained.
A review of arrhythmia symptoms was conducted by telephone interview at 9 months and every 6 months thereafter. Patients were asked to provide a weekly trans-telephonic electrocardiogram recording during the study, and to transmit them whenever symptoms of arrhythmia were felt. All follow-up assessments were performed by study personnel who were unaware of the treatment assignments.
The 1-year Kaplan-Meier event rate estimates were 10.2% for cryoballon ablation and 12.8% radiofrequency ablation (HR 0.78, 95% CI 0.52-1.18), the authors reported.
The most common safety events were groin-site complications which were seen in 16 patients undergoing radiofrequency ablation and in seven in the cryoballoon group. Phrenic-nerve injury occurred in 10 patients undergoing cryoballoon ablation. No atrioesophageal fistulae, pulmonary-vein stenoses, or procedure-related deaths were observed.
The authors noted that procedure duration and left atrial dwell time were shorter in the cryoballoon abalation group — most likely because of single-step circumferential abalations — while fluroscopy time was shorter in the radiofrequency ablation group.
The group also noted some study limitations, most notably that the case-report form used did not record individualized secondary catheter performance characteristics, and for the cryoballoon catheter, the study did not record pulmonary-vein occlusion scores, time to pulmonary-vein isolation, the duration of the freezing procedure, or the number of freezes.
Also, for the radiofrequency catheter group, there was no data on application times, contact-force measurements, peak wattage, or three-dimensional mapping variables.
Kenneth Ellenbogen, MD, of the Virginia Commonwealth University School of Medicine in Richmond, called FIRE AND ICE “a really pivotal study for the field of catheter ablation,” and noted several key messages from the findings.
“One take-home message from this [trial] is that both radiofrequency energy and cryoballoon ablation of atrial fibrillation provide similar outcomes with respect to atrial fibrillation recurrence over the period of time these patients were studied. These patients were in the hands of people who were technically good at doing both procedures,” said Ellenbogen, who was not involved in the study.
“The second take-home message is that the safety of both techniques is fairly similar,” added Ellenbogen, who is a spokesperson for the American Heart Association.
Finally, “the third take-home message is that patients do fairly well, and the risk of recurrence of atrial fibrillation is relatively low over time, although atrial fibrillation recurrences occurred throughout the trial,” he said.
The study was funded by Medtronic.
Kuck and some co-authors disclosed relevant relationships with Biosense Webster, Edwards, Medtronic, and St. Jude.
Ellenbogen disclosed no relevant relationships with industry.
Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
last updated 04.05.2016
‘Hot,’ ‘Cold’ Ablation Prove Equal in Afib – MedPage Today