BOSTON—Preliminary results of a randomized trial found the HeartLight visually-guided laser balloon (VGLB) system was as safe and effective as irrigated radiofrequency ablation in patients with paroxysmal atrial fibrillation (PAF).
Lead researcher Vivek Y. Reddy, MD, of Mount Sinai School of Medicine in New York, said 61.1 percent of patients in the VGLB group and 61.7 percent of patients in the radiofrequency ablation group met the primary efficacy endpoint of freedom from AF at 12 months. He presented the results on May 15 during a late-breaking clinical trials session at Heart Rhythm 2015.
The HeartLight VGLB system (CardioFocus) is an investigational device and is not FDA-approved. CardioFocus funded the trial.
Primary adverse events were found in 11.8 percent of patients in the VGLB group and 14.5 percent of patients in the radiofrequency ablation group. After excluding cardioversions, the clinical primary adverse event rates were 5.3 percent and 6.4 percent, respectively.
The mean procedure time was 236 minutes with VGLB and 193 minutes with radiofrequency ablation, while the mean ablation time was 173.8 minutes and 151.2 minutes, respectively. Both differences were statistically significant.
Single procedure success was found in 61.1 percent of patients in each group.
The study randomized 353 patients at 21 sites in the U.S. who were between 18 and 75 years old, failed at least one antiarrhythmic drug, had at least two symptomatic episodes of AF and at least one documented episode of AF in the past year. Patients were excluded if they had more than four cardioversions within the past year and had an average pulmonary vein diameter greater than 35 mm.
Patients in the radiofrequency ablation group were allowed to have had nonpulmonary vein ablation performed as well as a re-do procedure during the first three months. Patients in the VGLB group could not have a re-do procedure. All patients had CT and MRIs performed at baseline, three months and 12 months if needed, Holter monitoring at six and 12 months and weekly event and symptom monitoring.
The operators were experienced with radiofrequency ablation, but they did not have much experience with VGLB. Before the study, only 23 percent of operators had performed more than five VGLB procedures and 7 percent had performed more than 10 such procedures. None of the operators had performed more than 100 VGLB procedures.
“With experience, you have improvements in efficacy and improvements in safety,” Reddy said. “In fact, one study suggests it’s after you do 100 procedures that your success rate really starts to increase into the 80-85 percent success rate. Will that happen with the laser balloon? I would guess yes. Of course, we need more data to really prove that.”
At baseline, there were no significant differences in the VGLB and radiofrequency ablation group. The mean age was approximately 60, while the mean duration of AF was approximately two years. Approximately 25 percent of patients had atrial flutter, and 9 percent had undergone ablation for atrial flutter.
Reddy noted that six patients in the VGLB group had phrenic nerve injury compared with one patient in the radiofrequency ablation group. Of the three patients in the VGLB group whose phrenic nerve injury lasted beyond a year, two had completely resolved and the third was improving and likely to resolve soon, according to Reddy.
At the three-month follow-up, pulmonary vein narrowing occurred in 21.9 percent of VGLB patients and 24.7 percent of radiofrequency ablation patients, while pulmonary vein stenosis occurred in zero and five patients, respectively.