Global utilization and outcomes of first-line cryoablation for atrial fibrillation

Background Recent trials demonstrated the safety and efficacy of cryoballoon ablation prior to antiarrhythmic drug (AAD) usage in patients with paroxysmal atrial fibrillation (AF); however, global utilization and outcomes of first-line cryoablation in real-world AF patient management are unknown. Purpose To evaluate baseline characteristics and outcomes in patients selected for first-line cryoablation for treatment of AF. Methods The Cryo Global Registry (NCT02752737) is an ongoing, prospective, multicenter registry. In this analysis, AF patients with an index cryoballoon ablation performed according to local standards of care at 58 centers in 26 global countries were included. Subjects with no prior failed antiarrhythmic drug (AAD) usage and not taking an AAD at baseline were considered first-line and compared to drug-refractory patients who had failed an AAD prior to enrollment in the study and/or were taking an AAD at baseline. Baseline characteristics, serious procedure-related complication rates, and 12-month freedom from a ≥30sec AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a 90-day blanking period were compared between the groups. Results In total, 31% of the 1,394 patients (433 first-line, 961 drug-refractory) received a first-line cryoablation. The proportion of first-line enrollments by world region (3.7%-53.5%) and countries within region (i.e. EU: 0–59%) varied widely. Drug-refractory patients failed a mean of 1.2±0.5 AADs prior to cryoablation. First-line and drug-refractory patients were similar in age (60±13 vs 61±11), sex (35.1% vs 36.8% female), and CHA2DS2-VASC (2.0±1.6 vs 2.1±1.6). First-line was more often paroxysmal AF (87.3% vs 80.2%), with lower BMI (27±5 vs 28±5), diagnosed with AF fewer years (2.1±3.9 vs 3.7±5.0), and had smaller left atrial diameters (39±7 vs 42±8 mm; all p<0.05). Hypertension and history of congestive heart failure were less common in first-line (p<0.05), but similar rates of prior myocardial infarction, stroke, coronary artery disease, diabetes, and sleep apnea were reported. Procedure, left atrial dwell, and cryoapplication times were similar between cohorts (all p>0.05). Serious adverse event rates were not statistically different between first-line and drug-refractory patients (2.3% vs 3.4%, respectively; p=0.32). Freedom from AF/AFL/AT after cryoablation in first-line vs drug-refractory PAF was 90.0% (95% CI: 86.4–92.7%) and 84.4% (95% CI: 81.5–86.8%) and in first-line vs drug-refractory persistent AF was 72.9% (95% CI: 58.6–83.0%) vs 70.2% (95% CI: 62.9–76.4%), respectively. First-line ablation resulted in higher rates of freedom from arrhythmia recurrence (p=0.02). Conclusion First-line cryoablation in a real-world setting resulted in improved efficacy without increasing the risk of a safety event. These data support cryoablation as an early intervention strategy for treatment of AF. FUNDunding Acknowledgement Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.