Double ablation does not improve AF recurrence rates compared to standard regimens: AWARE trial

Catheter ablation for atrial fibrillation (AF) is limited by AF recurrence in an estimated 11% to 47% of patients. Can an augmented (double) wide-area circumferential ablation (WACA) set reduce atrial arrhythmia recurrence in patients with paroxysmal atrial fibrillation?

The recently published AWARE trial has shown that additional ablation by performing a double ablation lesion set does not result in improved freedom from recurrent atrial arrhythmias (AA) compared with a standard single ablation set. The trial has been published in JAMA Cardiology journal.

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation techniques that have proven efficacious for patients with paroxysmal AF, but pulmonary vein (PV) electrical reconnection is the most common factor responsible for AF recurrence after ablation. Adenosine testing– and contact force–guided PVI are the most useful adjunctive measures to ensure durable PVI during ablation. However, even with contact force and adenosine testing to guide PVI, the 1-year recurrence rate of AF remains 33% to 40%.

The Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence (AWARE) trial compared the standard of care ablation technique of adenosine-guided wide-area circumferential ablation (WACA) with a novel augmented (double) WACA technique. The hypothesis was that the wider area of atrial ablation would increase the chance of durable PVI, thereby resulting in reduction of atrial arrhythmias (AA) (atrial tachycardia, atrial flutter, or AF) without affecting procedural safety.

This was a pragmatic, multicenter, prospective, randomized, open, blinded end point superiority clinical trial. Patients were randomized (1:1) to receive radiofrequency catheter ablation for pulmonary vein isolation with either a standard single WACA or an augmented double WACA.

The primary outcome was AA recurrence between 91 and 365 days postablation. Patients underwent 42 days of ambulatory electrocardiography monitoring after ablation. Secondary outcomes included need for repeated catheter ablation and procedural and safety variables.

Of 398 patients, 195 were randomized to the single WACA (control) and 203 to the double WACA (experimental) arm.

Overall, 26.7% in the single WACA arm and 24.6% in the double WACA arm had recurrent AA at 1 year (P = 0.64). 10.3% in the single WACA arm and 7.4% in the double WACA arm underwent repeated catheter ablation (relative risk, 0.72).

Adjudicated serious adverse events occurred in 13 patients (6.7%) in the single WACA arm and 14 patients (6.9%) in the double WACA arm.

To summarise the results, in patients with paroxysmal AF, an ablation strategy using routine delivery of a second circumferential line of ablation did not show any additional benefit in preventing AA recurrence at 1 year.

More is not always better:

“This (results) suggests that more is not necessarily better when it comes to ablation of paroxysmal AF. This message is consistent with results of the Substrate and Trigger Ablation for Reduction of Atrial Fibrillation (STAR AF II) RCT in patients with persistent AF that failed to show benefit of additional extra-pulmonary ablation lesion sets”, note the authors in discussion. They further add, “this suggests that here may be a ceiling effect to the single procedure success of empirical WACA in patients with paroxysmal AF”.

Overall, these findings are consistent with prior research in catheter ablation in patients with persistent AF, where empirical adjunctive ablation strategies failed to reduce AA recurrence.

Source: JAMA Cardiology: doi:10.1001/jamacardio.2023.0212