medwireNews: Findings from the aMAZE trial indicate that adjunctive left atrial appendage ligation is no better than pulmonary vein isolation alone at preventing atrial arrhythmias in patients with nonparoxysmal atrial fibrillation (AF).
“The results do not support adjunctive left atrial appendage ligation plus pulmonary vein isolation in the overall nonparoxysmal atrial fibrillation population undergoing initial atrial fibrillation ablation,” Dhanunjaya Lakkireddy (Kansas City Heart Rhythm Institute, Overland Park, USA) and colleagues say.
They note, however, that “percutaneous left atrial appendage ligation adjunctive to pulmonary vein isolation met prespecified safety criteria and demonstrated high rates of closure at 12 months.”
The study was conducted at 53 US sites and involved 610 patients who had nonparoxysmal AF for a duration of up to 3 years and had been unsuccessfully treated with at least one class I/III anti-arrhythmic drug.
The participants were randomly assigned to undergo left atrial appendage ligation plus pulmonary vein isolation (n=404) or pulmonary vein isolation alone (n=206) from 2015 to 2019. Of these participants, 378 and 198, respectively, were included in the modified intention-to-treat and primary efficacy analyses.
“This trial was based on the premise that left atrial appendage ligation creates left atrial appendage ischemic necrosis, atrophy, and resorption leading to left atrial appendage electrical isolation and a reduction of left atrial appendage tissue,” explain Lakkireddy et al.
The median age of the participants was 68 years, 73% were men and over 94% were White. The mean duration of AF was 4.7 months and 79% of patients had persistent AF lasting less than 6 months. Left atrial volume was a median 131.7 mL in the left atrial appendage ligation group and 137.9 mL in the pulmonary vein isolation alone group.
The results, published in JAMA, show that 12 months after left atrial appendage ligation plus pulmonary vein isolation, 64.3% of patients had not experienced an episode of atrial arrhythmia lasting more than 30 seconds nor required new or increased doses of anti-arrhythmia drug treatment. This was similar to the 59.9% rate among patients undergoing pulmonary vein isolation alone, with a difference of just 4.3 percentage points and a Bayesian probability of 0.835, which did not meet the prespecified probability criterion of 0.977 to demonstrate superiority of adjunctive left atrial appendage ligation.
Left atrial appendage ligation was technically successful for most of the patients, with complete closure seen in 84% at 12 months, while 99% had residual communication with the left atrium of less than or equal to 5 mm.
Serious adverse events at 30 days occurred in 3.2% of patients undergoing adjunctive left atrial appendage ligation, compared with 3.5% of patients receiving pulmonary vein isolation alone. The Bayesian probability was 3.4%, which was well within the prespecified safety goal of 10.0%. The adverse events included eight cases of bleeding, three cases of cardiac injuries requiring surgical intervention, and one vascular injury requiring surgical treatment.
“Stroke prevention was not a study endpoint, but future studies for this outcome are warranted because the device appears to be effective for left atrial appendage exclusion and the safety performance goal of the trial was met,” the investigators suggest.
They also point out that “[i]nvestigators bias to target non-pulmonary vein substrate in late persistent and long-standing persistent atrial fibrillation may have reduced enrollment of those patients for whom left atrial appendage ligation benefit may be expected to be more prominent, thus diluting overall treatment effect.”
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