ASTRO AF: No benefit of staged left atrial appendage isolation cryoballoon ablation over radiofrequency ablation

Staged cryoballoon left atrial appendage isolation (LAAI) and interventional left atrial appendage closure (LAAC) showed no benefit over radiofrequency ablation with 3D mapping in participants with symptomatic atrial fibrillation (AF) and durable pulmonary vein isolation in the ASTRO AF trial.

ASTRO AF (NCT04056390) is a multicentre, randomised trial comparing empirical ablation with LAAI using a cryoballoon and staged interventional LAAC with an individualised technique consisting of ablation of left atrial low voltage areas (LVA) using an irrigated radiofrequency current and a 3D mapping system [1].

Participants were included if they had symptomatic AF (no atrial tachycardia) despite prior pulmonary vein isolation. The primary endpoint of the trial was arrhythmia-free survival between days 90 and 365 following ablation. In total, 161 participants were randomised, of whom 32% had paroxysmal AF and 66% had permanent AF; 47% of the participants had 1 prior ablation procedure, and 40% had 2 prior procedures. Dr Boris Schmidt (Cardioangiologisches Centrum Bethanien, Germany) presented the results.

Using 72-hour Holter measurements at 3, 6, and 12 months, no statistically significant difference was found between groups in terms of arrhythmia-free survival (P=0.81). At the 12-month timepoint, the arrhythmia-free survival rate with LAAI/LVA was 51.7%, compared with 55.5% with the radiofrequency procedure. In terms of safety, there was a numerically higher number of complications in the LAAI/LVA group (13.4% vs 5.0%; P=0.1022).

In summary, the primary endpoint of the trial was not met, with cryoballoon LAAI/LVA not proving superior to radiofrequency ablation. Due to these results, Dr Schmidt stressed that “the study was prematurely halted for futility after randomisation of 63% of the planned patient population.”

1. 
   
   1. Schmidt B, et al. Ablation STrategies for Repeat PrOcedures in patients with Atrial Fibrillation recurrences despite durable pulmonary vein isolation. Late-Breaking Science: ablation. EHRA Congress 2024, 7–9 April, Berlin, Germany.

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Posted on 29 April 202430 April 2024