The recent publication of FIRE AND ICE, a large randomized trial comparing the cryoballoon (CB) to radiofrequency catheter (RF) ablation to perform pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF), demonstrated that CB ablation was noninferior to RFA with respect to efficacy and was associated with similar safety.1 Although the trial was limited by unequal changes in the ablation tools used in each arm during the course of the study, with use of contact-force sensing in only about one-quarter of the RF cases compared to use of the second-generation cryoballoon in about three-quarters of the cryo cases, neither camp could declare superiority.
However, new preliminary data from FIRE AND ICE based on predetermined secondary study endpoints were presented at the recent CARDIOSTIM-EHRA EUROPACE 2016 conference on June 10th, and demonstrated superiority of cryoablation with regard to re-hospitalization and redo ablation procedures.2 The use of the CB was associated with a markedly lower overall hospitalization after the ablation procedure compared to RF; the effect appeared to be driven entirely by a reduction in cardiovascular hospitalization from 36% in the RF group to 24% in the CB group (p<0.001). The benefit in cardiovascular hospitalization appeared to be present across all patient subgroups. Equally impressive was the lower rate of repeat ablation procedures in the CB group at 12% compared to 18% in the RF group (p=0.03). Furthermore, use of the CB was associated with a lower rate of cardioversion after the ablation procedure at 3% compared to 6%, related mostly to a lower need for cardioversion shortly after the procedure. Quality of life data indicated that patients in both groups improved with no differences between the two groups.
The FIRE AND ICE study has established that the CB is at least as good as RF as an ablation tool for patients with PAF. The recent data on re-hospitalizations and redo ablation procedures suggests that the CB might be better. What is interesting about the most recent data demonstrating an advantage of CB over RF for PVI is that, unlike the primary endpoint data, they include data from the 90-day blanking period. These new data suggest that although the long-term outcomes may be similar between the CB and RF when accounting for the healing phase, the patient experience during the first few weeks after the procedure may be better with the CB.
- Kuck KH, Brugada J, Furnkranz A, et al. Cryoballoon or radiofrequency ablation for paroxysmal atrial fibrillation. N Engl J Med. 2016 Apr 4; [e-pub]. (http://dx.doi.org/10.1056/NEJMoa1602014).
- Kuck KH, et al. The FIRE AND ICE Trial Looking Beyond the Primary Safety and Efficacy Endpoints. Late-breaking Clinical Trial Presentation at Cardiostim 2016 June 8-10; Nice, France. (Abstract).