Efficacy and safety of a novel size-adjustable cryoballoon vs conventional cryoballoon: Results from the CONTRAST-CRYO II randomized clinical trial.
Yukihiro Inamura, Shinsuke Miyazaki, Junichi Nitta et al.
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In 30 seconds
The CONTRAST-CRYO II randomized clinical trial compared a size-adjustable cryoballoon (SACB) with a conventional cryoballoon (CCB) for pulmonary vein isolation in patients undergoing atrial fibrillation ablation. Among 219 patients, isolation success and 1-year arrhythmia-free rates were similar. Phrenic nerve injury, the primary outcome, occurred more often with SACB than CCB (7.3% vs 0.9%, P = .02), particularly during right inferior pulmonary vein ablation with the 31-mm balloon. All affected patients recovered during follow-up.
Key findings
- Pulmonary vein isolation success was 98.8% with SACB and 97.9% with CCB (P = .42).
- Phrenic nerve injury occurred in 7.3% with SACB versus 0.9% with CCB (P = .02); all patients recovered during follow-up.
- One-year arrhythmia-free rates were 88.5% with SACB and 89.7% with CCB (log-rank, P = .74).
- With SACB, 378 of 433 pulmonary veins (87.3%) were isolated using the 31-mm balloon.
Why it matters
The trial found comparable pulmonary vein isolation success and 1-year arrhythmia freedom with the two balloon systems, but a higher rate of phrenic nerve injury with the size-adjustable device. The concentration of injuries during right inferior pulmonary vein ablation with the 31-mm balloon is relevant to procedural safety assessment, although all reported injuries resolved during follow-up.
What to keep in mind
Follow-up was 12 months, so the study does not establish longer-term arrhythmia outcomes.