Long-Term Outcomes After Ablation for Paroxysmal Atrial Fibrillation Using the Second-Generation Cryoballoon: Final Results From STOP AF Post-Approval Study.

OBJECTIVES

STOP AF PAS (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study) is the first prospective, multicenter, 3-year study in North America to assess long-term safety and effectiveness of the cryoballoon for treatment of patients with drug-refractory symptomatic pAF.

BACKGROUND

The STOP AF PAS was required by the U.S. Food and Drug Administration at the time of approval of the first-generation cryoballoon for the treatment of paroxysmal atrial fibrillation (pAF). The second-generation cryoballoon (CB2) was commercially released shortly after this trial was initiated.

METHODS

The study was nonrandomized. Enrollment was completed with 344 eligible patients undergoing pulmonary vein isolation (PVI) using the CB2. Procedure-related safety and freedom from AF and symptomatic atrial flutter/atrial tachycardia through 3 years were determined. Documented atrial arrhythmias ≥30 s were considered treatment failures.

RESULTS

Acute PVI was achieved in 99.3% (1,341 of 1,350) of veins. Mean follow-up was 34 ± 7 months. The rate of major complications was 5.8%, including a 3.2% rate of phrenic nerve injury, which resolved in all but 1 patient by 36 months. At 36 months, 11.7% of patients were prescribed antiarrhythmic agents, inclusive of "pill-in-the-pocket" administration. Freedom from AF was 81.6% at 12 months, 73.8% at 24 months, and 68.1% at 36 months. Freedom from AF and symptomatic atrial flutter/atrial tachycardia was 79.0% at 12 months, 70.8% at 24 months, and 64.1% at 36 months. Freedom from a repeat ablation procedure was 80.9% at 36 months.

CONCLUSIONS

PVI using the CB2 was an effective treatment for patients with pAF, with freedom from all atrial arrhythmias of 64% at 36 months. (Sustained Treatment of Paroxysmal Atrial Fibrillation Post-Approval Study [STOP AF PAS]; NCT01456949).