Catheter ablation outcomes in patients with AF vary by age: CABANA
Compared with drug therapy, there was age-based variation in catheter ablation clinical outcomes among patients with atrial fibrillation, with the largest benefits observed in younger patients, according to new data from the CABANA trial.
“The CABANA trial was the first large prospective randomized trial with extended follow-up to compare catheter ablation to drug therapy with regard to mortality-inclusive outcomes in a diverse patient population that included a broad spectrum of ages and all AF types,” Tristram D. Bahnson, MD, professor of medicine at Duke University School of Medicine and the Duke Center for Atrial Fibrillation in the Duke Health System, and colleagues wrote in Circulation. “As previously reported, the trial showed that catheter ablation had an inconclusive effect on the primary composite study outcome (a composite of death, disabling stroke, serious bleeding or cardiac arrest) and on all-cause mortality. The secondary outcomes of AF recurrence, quality of life and the composite of mortality and cardiovascular hospitalization showed clinically consequential benefits of catheter ablation compared to drug therapy.”
Outcomes according to age
The prespecified subgroup analyses included 2,204 patients with AF with at least one risk factor for stroke. Patients were stratified by age (65 years or older or younger than 65 years). All patients were randomly assigned to receive either catheter ablation or drug therapy. Of all patients, 34.8% were younger than 65 years, 51.3% were aged between 65 and 74 years and 14% were 75 years or older.
The primary outcome was a composite of mortality, disabling stroke, serious bleeding or cardiac arrest.
Treatment effect varies
Catheter ablation was associated with a 43% reduction in primary outcome for those aged younger than 65 years (adjusted HR = 0.57; 95% CI, 0.3-1.09), a 21% reduction among those aged 65 to 74 years (aHR = 0.79; 95% CI, 0.54-1.16) and no reduction in those aged 75 years or older (aHR = 1.39; 95% CI, 0.75-2.58).
Compared with drug therapy, 4-year event rates for catheter ablation were lower for those younger than 65 years (3.2% vs. 7.8%) and 65 to 74 years (7.8% vs. 9%) but not for those aged 75 years or older (14.8% vs. 9%). Every 10-year increase in age corresponded to an increase of an average of 27% in the aHR for the primary outcome (P for interaction = .215), making catheter ablation less favorable to older patients. Researchers observed similar patterns for all-cause mortality, with an increase in the aHR of 46% for each 10-year increase in age (P for interaction = .111).
Also, compared with drug therapy, AF recurrence rates were lower with catheter ablation among those aged younger than 65 years (aHR = 0.47; 95% CI, 0.35-0.62), those aged 65 to 74 years (aHR = 0.58; 95% CI, 0.48-0.7) and those aged 75 years and older (aHR = 0.49; 95% CI, 0.34-0.7).
Treatment-related complications were infrequent among patients who received catheter ablation and those who received drug therapy regardless of their age.
“The primary findings of this investigation confirm that treatment benefit assessed on both relative and absolute scales varied as a function of age, with older patients having progressively small incremental prognostic benefits from catheter ablation,” the researchers wrote.
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