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.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

Healthcare utilization after cryoballoon ablation for treatment of atrial fibrillation in patients with heart failure: real-world results from the Cryo AF Global Registry

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

OnBehalf

Cryo AF Global Registry Investigators

Background

Heart failure (HF) concomitant to atrial fibrillation (AF) can exacerbate the risk of hospitalization, morbidity, mortality, and impairment in quality of life posed by each condition alone. While the reciprocal relationship between HF and AF challenges effective treatment for these patients, catheter ablation for treatment of AF is reasonable for select patients with AF and HF according to guidelines. Purpose: Assess real-world usage and healthcare utilization outcomes of cryoablation for patients with AF and HF. Methods: The Cryo AF Global Registry (NCT02752737) is an ongoing, prospective, multicenter registry. Patients with AF were enrolled and treated with cryoballoon ablation (Arctic Front Advance, Medtronic) according to clinical practice at 56 sites in 26 countries world-wide. Subjects with NYHA class I-III at baseline comprised the HF cohort and were compared to patients without HF (No-HF). Freedom from atrial arrhythmia recurrence ≥30 sec, adverse events associated with the AF ablation procedure, repeat ablations, AAD usage, and cardiovascular rehospitalization over a 12-month follow-up were compared between cohorts. Results: A total of 1,303 patients (318 HF, 985 No-HF) were included. The HF cohort included patients with NYHA Class I (56.3%) and II/III (43.7%) with either preserved (81.6%) or mid/reduced (18.4%) left ventricular ejection fraction. HF patients were more often female (45.6% vs 33.6%) with persistent AF (25.8% vs 14.3%), larger left atrial diameter (4.4 ± 0.9 vs 4.0 ± 0.7 cm), and higher rates of hypertension (67.9% vs 49.1%) and prior myocardial infarction (3.8% vs 1.7%; all, P < 0.05). The rate of serious procedure-related complications was 5.3% in HF and 3.0% in No-HF (P = 0.08). Freedom from atrial arrhythmia recurrence at 12-months was not different between HF and No-HF patients with either paroxysmal (84.2% (95% CI:78.6-88.4) vs 86.8% (95% CI: 84.2 – 89.0)) or persistent AF (69.6% (95% CI: 58.1 – 78.5) vs 71.8% (95% CI: 63.2-78.7)), respectively (p = 0.32, HF vs No-HF). AF-related symptoms and antiarrhythmic drug use were significantly reduced after cryoablation in the HF and No-HF cohorts (P < 0.05). Freedom from repeat ablation at 12-months was similar between HF and No-HF patients. Of patients who had a cardiovascular rehospitalization after cryoablation, 78% presented with a supraventricular tachyarrhythmia. Persistent AF and HF at baseline both increased the risk of cardiovascular rehospitalization after cryoballoon ablation (P < 0.05). Conclusion: Cryoablation is used to treat patients with AF and concomitant HF in real-world practice and is similarly safe and effective at 12-months in patients with and without HF.

Safety of cryoballoon ablation for the treatment of atrial fibrillation: first European results from the Cryo AF Global Registry

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Medtronic, Inc.

OnBehalf

Cryo AF Global Registry Investigators

Background

Since introduced in Europe over 15 years ago, cryoballoon ablation for the treatment of

patients with atrial fibrillation (AF) has proven to be safe and effective.

Purpose

Report on patient and procedural characteristics, ablation techniques, and outcomes. Also,

determine the independent predictors of a procedural adverse event in real-world usage.

Methods

Patients with AF were enrolled in the prospective, multicenter Cryo AF Global Registry

(NCT02752737) and treated with cryoballoon ablation at 38

European centers according to standard-of-care. The primary efficacy endpoint was freedom from a ≥30 sec episode of AF/atrial flutter (AFL)/atrial tachycardia (AT) at 12-months. The primary safety endpoint was the rate of serious adverse events related to the device and/or procedure. Univariate and

multivariable models identified baseline patient and procedural characteristics that predicted a serious

procedure-related complication. Results: Of 1,418 subjects who completed an index procedure, the cohort was 62 ± 11 years of age, 37.7% female, and 72.2% paroxysmal AF (PAF). In total, 32.2% of patients were treated with cryoablation as a first-line therapy. Non-general anesthesia was used in 76.0% of procedures. Ablation adjunctive to the cryoballoon pulmonary vein isolation was applied in few cases: 2.0% of patients were treated with a cavotricuspid isthmus (CTI) line with focal radiofrequency ablation and 0.8% of patients received other non-PVI ablation. The mean procedure, left atrial dwell, and fluoroscopy times were 81 ± 34, 54 ± 25, and 14 ± 13 minutes, respectively. Among the 766 patients with 12-month follow-up, freedom from AF/AFL/AT recurrence ≥30 sec was 83.3% (95% CI: 79.8-86.3%) and 71.6% (95% CI: 64.6-77.4%) in patients with PAF and persistent AF, respectively. The serious procedure- and device-related adverse event rates were 4.7% and 2.0%, respectively. Female sex was significantly associated with the occurrence of an adverse event in univariate analysis (P < 0.05), but (after accounting for patient age and NYHA status) no baseline patient characteristic independently predicted a procedure-related adverse event. However, prolonged procedure duration (OR = 1.01 (95% CI: 1.00-1.01)), use of general anesthesia (OR = 1.71 (95% CI: 1.01 – 2.92)), and delivery of a CTI line (OR = 3.04 (95% CI: 1.01-9.20) were each independently associated with the occurrence of a serious procedural safety event (all P < 0.05). Conclusion: Cryoablation treated patients across the AF disease spectrum with one-third of patients treated prior to antiarrhythmic drug usage and another third treated for persistent AF. The results indicate extra diligence is warranted in patients under general anesthesia and for those who receive adjunctive CTI ablation. Cryoballoon ablation is consistently safe for patients independent of baseline patient characteristics and comorbidities in real-world use.