CABANA: Catheter ablation reduces AF recurrence through 5 years
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At 5 years, patients with atrial fibrillation assigned catheter ablation had reduced recurrence of any AF compared with those assigned drug therapy, according to new data from the CABANA trial.
“These data support the finding of smaller trials that catheter ablation is superior to drug therapy to prevent recurrent AF,” Jeanne E. Poole, MD, professor of medicine in the division of cardiology and section head of electrophysiology at University of Washington in Seattle, told Healio. “CABANA was the largest trial conducted comparing a strategy of ablation to drug therapy, and across a broad group of patients with cardiovascular comorbidities. Our findings support catheter ablation as an important strategy which can be offered to patients with AF.”
AF monitoring
Researchers analyzed data from 1,240 patients (median age, 68 years; 34% women; 43% with paroxysmal AF) from the CABANA trial who had AF and were assigned catheter ablation (n = 611) or drug therapy (n = 629).
The main results of the CABANA trial determined that catheter ablation conferred better outcomes compared with drug therapy in patients with AF in the on-treatment and per-protocol analyses, but not in the intention-to-treat analysis. As Healio previously reported, at a median follow-up of 4 years, for the primary endpoint of death, disabling stroke, serious bleeding or cardiac arrest, the difference between patients assigned ablation and those assigned drug therapy was not significant in the intention-to-treat analysis (HR = 0.86; 95% CI, 0.65-1.15), but favored ablation in both the on-treatment analysis (HR = 0.67; 95% CI, 0.5-0.89) and the per-protocol analysis (HR = 0.73; 95% CI, 0.54-0.99).
For the current study, all patients were observed for symptom-activated and 24-hour AF auto-detection with a proprietary ECG system. Researchers assessed AF burden every 6 months with 96-hour Holter monitoring.
The endpoint of interest — AF recurrence — was defined as any post-90-day blanking atrial tachyarrhythmias that lasted for 30 seconds or longer.
Patients assigned catheter ablation had significant reduction in asymptomatic AF (HR = 0.52; 95% CI, 0.45-0.6) and first symptomatic-only AF (HR = 0.49; 95% CI, 0.39-0.61) during 60 months of follow-up.
Both treatment groups had a baseline Holter AF burden of 48%. AF burden at 12 months was 6.3% in patients assigned catheter ablation and 14.4% in those assigned drug therapy. During 5 years of follow-up, the catheter ablation group had significantly less AF burden compared with the drug therapy group (14.7% vs. 20.8%; P < .001).
AF burden reduction in patients assigned catheter ablation did not differ by AF pattern at baseline.
“It is not clear what the best endpoint is to determine successful ablation, and it may vary amongst different patients,” Poole said in an interview. “We demonstrated positive results for catheter ablation when looking at AF burden. That finding is novel in that we included patients with persistent and longstanding persistent AF. Further studies exploring AF burden or other measures of recurrence such as AF density are needed to assess outcomes on quality of life, hospitalization or mortality.”
‘Clear benefit’
In a related editorial, Francis E. Marchlinski, MD, director of electrophysiology at the University of Pennsylvania Health system, director of the electrophysiology laboratory at the Hospital of the University of Pennsylvania and Richard T. and Angela Clark President’s Distinguished Professor at the University of Pennsylvania Perelman School of Medicine, and colleagues wrote, “The CABANA trial report on late AF recurrence confirms the clear benefit of catheter ablation vs. pharmacological therapy in preventing recurrent AF in patients with symptomatic AF, and is important in being one of the largest prospective studies to report on the benefit of catheter ablation on AF burden. Clearly, a burden assessment should be part of the reporting standards for assessing efficacy of therapy in preventing AF recurrence.”
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For more information:
Jeanne E. Poole, MD, can be reached at jpoole@u.washington.edu; Twitter: @jepoolemd.
Perspective
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Jonathan S. Steinberg, MD
These findings do not add a lot to the knowledge base. This trial previously showed that AF is reduced and quality of life is improved in the catheter ablation arm, which is also not novel in that many other trials in various AF populations have shown the superiority of ablation therapy to drug therapy.
The new findings may generate interest as they derive from a very large study that has long follow-up. There was a systematic schedule of these recordings, which adds additional heft to the findings of this study in its prior publications and also to prior studies across the AF spectrum.
It is confirmatory of what we have seen in other rigorous clinical trials and also what we observe in real-world clinical practice.
The findings confirm the concept that AF ablation has an important role in symptomatic patients, particularly if they have not responded readily to antiarrhythmic drugs either because they have been ineffective or poorly tolerated.
It is important to highlight that many patients enrolled in this trial had previously been exposed to antiarrhythmic drugs. Each arm had a median of one prior drug treatment, which means that the patients who entered this trial, in essence, are drug failures, which makes them less likely to respond to subsequent antiarrhythmic drugs and certainly unlikely to respond to continued antiarrhythmic drug therapy. It is not surprising that the drug arm fared less well than the interventional arm.
We have really done a good job in solidifying the role of AF ablation for paroxysmal and persistent AF in symptomatic patients who have not responded to drug therapy and select patients who haven’t been exposed to drugs but prefer an interventional approach. We have made enormous progress in refining the ideal methods for ablation therapy and tremendous progress in making the procedure safe in experienced hands.
The future of AF ablation research will focus on technical alternatives to current techniques. We still need improved interventional approaches for the subgroup of patients with AF who present to the laboratory with a history of persistent AF. The results of ablation, although better than drugs, are still suboptimal. We need to keep working on innovative approaches in this population such as the work that I am focusing on, which is renal denervation therapy or other forms of autonomic neuromodulation.
There is an opportunity also to determine whether prophylactic AF ablation is valuable in patients who have not yet exhibited clinical AF such as those patients who present with typical atrial flutter.
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