CHICAGO — In patients with drug-refractory paroxysmal atrial fibrillation enrolled in the FIRE AND ICE trial, cryoballoon ablation was noninferior to radiofrequency ablation for efficacy, and the two technologies yielded similar safety.
Karl-Heinz Kuck, MD, PhD, head of cardiology at St. Georg Hospital in Hamburg, Germany, and colleagues enrolled 769 patients with symptomatic paroxysmal AF that was refractory to antiarrhythmic drugs or beta-blockers. Patients were enrolled at 16 centers in eight countries. Patients were randomly assigned to undergo ablation with pulmonary vein isolation attempted with cryoballoon catheters (Artic Front/Arctic Front Advance, Medtronic) guided by fluoroscopy or radiofrequency ablation catheters (ThermoCool/ThermoCool SF/ThermoCool SmartTouch) guided by CARTO 3D mapping.
The modified intent-to-treat population included 376 patients in the radiofrequency ablation group and 374 in the cryoballoon ablation group. The per-protocol population included 352 patients in the radiofrequency group and 341 in the cryoballoon group who did not have a major protocol violation.
Follow-up was conducted during in-person visits at 3 months, 6 months and then every 6 months thereafter. Mea follow-up was about 18 months.
The primary efficacy endpoint was first documented clinical failure, including AF recurrence, atrial flutter or atrial tachycardia, repeat ablation or use of antiarrhythmic drugs, at 90 days after ablation. The composite primary safety endpoint included death, cerebrovascular events or serious treatment-related adverse events.
At ACC 2016, Kuck reported no difference between cryoballoon or radiofrequency ablation in the primary efficacy endpoint. In the modified ITT analysis, documented clinical failure occurred in 143 patients in the radiofrequency group vs. 138 in the cryoballoon group within the first 12 months after the procedure (1-year Kaplan-Meier event rate estimates, 34.6% vs. 35.9%, respectively; HR = 0.96; 95% CI, 0.76-1.22; P < .001 for noninferiority). In the per-protocol analysis, the primary efficacy endpoint occurred in 118 patients in the cryoballoon group vs. 131 in the radiofrequency group (1-year Kaplan-Meier event-rate estimates, 31.9% vs. 35%, respectively; HR = 0.91; 95% CI, 0.71 to 1.17; P < .001 for noninferiority).
The mean procedure time was 124 minutes in the cryoballoon group vs. 141 minutes in the radiofrequency group and mean fluoroscopy time was 17 minutes in the radiofrequency group vs. 22 minutes in the cryoballoon group (P < .001 for both). Patients in both groups had similar time to first hospitalization for CV causes.
With regard to safety, the primary safety endpoint occurred in 40 patients in the cryoballoon group vs. 51 patients in the radiofrequency group (1-year Kaplan-Meier event-rate estimates, 10.2% vs. 12.8%, respectively; HR = 0.78; 95% CI, 0.52-1.18; P = .24).
Phrenic nerve injury at discharge was the most common safety event observed in the cryoballoon group (2.7% vs. 0%; P < .001) and groin-site complication was the most common safety event observed in the radiofrequency group (4.3% vs. 1.9%; P = .09).
“Our findings show for the first time that a simplified approach is as good as the more complex procedure,” Kuck said during the press conference. ... “Future consensus documents will use [these] trial data, and more patients will benefit from catheter ablation.”
The next step, he said, is to evaluate the safety and efficacy of these two technologies in patients with more advanced AF. – by Tracey Romero
Kuck KH, et, al. Joint ACC/NEJM Late-Breaking Clinical Trials IV. Presented at: American College of Cardiology Scientific Session; April 2-4, 2016; Chicago.
Kuck FH, et al. N Engl J Med. 2016; doi:10.1056/NEJMoa1602014.
Disclosure: The FIRE AND ICE trial was partially funded by Medtronic. Kuck reports receiving consultant fees for Biosense Webster, Edwards LifeSciences, Medtronic and St. Jude Medical.