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Visually guided laser balloon noninferior to radiofrequency ablation for pulmonary vein isolation
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BOSTON — A visually guided laser balloon was noninferior to standard-of-care radiofrequency ablation for pulmonary vein isolation in patients with paroxysmal atrial fibrillation, according to results of the HEARTLIGHT study.
The noninferiority finding is particularly meaningful because operators had much less experience with using the visually guided laser balloon (HeartLight Endoscopic Ablation System, CardioFocus) than with performing radiofrequency ablation, Vivek Y. Reddy, MD, director of cardiac electrophysiology at Mount Sinai Hospital, said during a press conference at the Heart Rhythm Society Annual Scientific Sessions.
Vivek Y. Reddy
“Each of the physicians has performed hundreds, if not thousands, of radiofrequency ablation procedures,” he said. “In contrast, physicians in the HEARTLIGHT study had relatively little experience using the laser balloon, even at the conclusion of the study. Most operators had never performed a laser balloon ablation, and none had performed more than 50 procedures. Despite that, there was similar efficacy. In the European experience, with increased experience, there were significant improvements in efficacy and safety.”
Reddy and colleagues randomly assigned 353 patients with paroxysmal AF (mean age, 60 years; 34% women) to pulmonary vein isolation via visually guided laser balloon or radiofrequency ablation.
“Right now, we use point-by-point ablation in the majority of patients who undergo ablation,” he said. “It’s technically complex to make all those point-by-point lesions contiguous. This new technology is a balloon with a camera, so one is identifying exactly where one lesion is, and how much overlap there is with the next lesion. At least in theory, one should be able to achieve continuous lesions all the way around.”
The primary efficacy outcome was freedom from AF at 1 year. Failure modes included a symptomatic episode of AF lasting at least 1 minute after a 90-day blanking period, failure to isolate all clinically relevant pulmonary veins, a left atrial procedure during follow-up, ablation-induced left atrial flutter or AF, and any Class I, II or III antiarrhythmic drug given for AF after ablation.
The primary safety outcome was a comparison of primary adverse events, including stroke, transient ischemic attack, major bleeding, perforation/tamponade/significant pericardial effusion, pulmonary vein stenosis, MI, diaphragmatic paralysis, atrio-esophageal fistula, AF or atrial flutter requiring cardioversion and device- or procedure-related death.
Reddy said procedure time and ablation time were longer for the laser balloon group (P < .0001 for both), which was likely due to operator inexperience with the procedure.
The rate of primary adverse events was similar in both groups (laser balloon group, 11.8%; radiofrequency group, 14.5%; P for noninferiority = .002), and remained so when cardioversions were excluded (laser balloon group, 5.3%; radiofrequency group, 6.4%), Reddy said.
There were six cases of phrenic nerve injury in the laser balloon group compared with one in the radiofrequency group. Of those in the laser balloon group, three were resolved within 1 year, two were resolved after 1 year, and one is in the process of being resolved, according to Reddy. There were no pulmonary vein stenoses in the laser balloon arm compared with five in the radiofrequency arm at 3 months and three at 1 year, though most were asymptomatic, he said.
The primary efficacy endpoint was also similar in both groups (laser balloon group, 61.1%; radiofrequency group, 61.7%; P for noninferiority = .003), and remained so when limiting the analysis to single-procedure success and when excluding those who failed only because of antiarrhythmic drug use. The success rate is similar to what was seen in the pivotal trials of other ablation technologies, Reddy said.
The laser balloon group had a higher rate of pulmonary veins isolated on first mapping (89.8% vs. 84%; P = .02).
The laser balloon system is not yet approved in the United States. – by Erik Swain
Reference:
Reddy VY, et al. Abstract LBCT02-06. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 13-16, 2015; Boston.
Disclosure: The study was funded by CardioFocus. Reddy reports receiving consulting fees/honoraria and research grants from Biosense Webster and CardioFocus.
Perspective
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Michael R. Gold, MD, PhD, FHRS
Although radiofrequency has been our standard energy source for decades for treating arrhythmias, the interest in alternative approaches has been an area of intense interest. Many potential alternatives have struck out, but cryoablation has become viable for certain applications.
This was an intriguing study evaluating laser balloon technology that allows visualization of the heart as well as ablation. The results are very promising. It was as good as radiofrequency ablation, with a higher success rate of pulmonary vein isolation with the first application, so this approach has the potential to shorten procedures. What will be really important is if we can demonstrate that there are more durable long-term lesions with laser.
As doctors move up the learning curve, the AF ablation success rate certainly won’t get worse and one would hope and expect that it will get better. How much better remains to be seen. My center was involved in the trial, although I wasn’t the one performing the procedures. Our ablationist who was doing the procedure commented on how nice a procedure it was, even when performing it the first or second time.
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