The benefits of catheter ablation in patients with heart failure and atrial fibrillation (AF) were found to be more limited in routine clinical practice compared with those observed in a clinical trial, according to a study published in Heart Rhythm.
Although in the Catheter Ablation for Atrial Fibrillation with Heart Failure (CASTLE-AF;
ClinicalTrials.gov identifier: NCT00643188), catheter ablation in participants with atrial fibrillation (AF) and HF was associated with a 40% reduction in the risk for all-cause mortality and HF hospitalization compared with conventional treatment, the study’s applicability to a wider routine practice population remains largely unknown.
In this retrospective cohort analysis, 289,831 adult patients with heart failure and AF were identified from a United States administrative database (mean age, 73.2±10.3 years; 47.6% women). In this cohort, patients were treated between January 2008 and August 2018 with catheter ablation (n=7465; mean age, 65.9±10.2 years; 34.5% women) or drug therapy alone (n=282,366; mean age, 73.4±10.2 years; 48.0% women). The cohort was divided according to CASTLE-AF trial eligibility criteria into 3 groups: 7.8% who would have been eligible, 91.0% who would not have met inclusion criteria, and 15.5% who would have met ≥1 exclusion criterion.
The study’s primary outcome was a composite of all-cause mortality and hospitalization for heart failure. Secondary outcomes included all-cause mortality, hospitalization for heart failure, cerebrovascular accident (CVA), and cardiac and all-cause hospitalization. The mean follow-up period was 1.8±1.8 years.
Patients who received ablation vs conventional treatment had a lower risk for the primary outcome in the entire cohort (hazard ratio [HR], 0.81; 95% CI, 0.76-0.87; P <.001), in the trial-eligible subgroup (HR, 0.82; 95% CI, 0.70-0.96; P =.01), and in the subgroup that would not have met CASTLE-AF inclusion criteria (HR, 0.79; 95% CI, 0.73-0.86; P <.001), but not the group that would have met CASTLE-AF criteria (HR, 0.97; 95% CI, 0.81-1.17; P =.75).
Reductions were observed in the entire cohort for the risk for all-cause mortality (HR, 0.67; 95% CI, 0.62-0.74; P <.001), but not for the risks for heart failure hospitalization (HR, 1.02; 95% CI, 0.94-1.10; P =.67) or CVA (HR, 0.98; 95% CI, 0.82-1.17; P =.81).
The relative risk reduction of ablation vs drug therapy was greater in men, individuals <65 years, and patients without a diagnosis of diabetes mellitus or implanted devices. This relative risk reduction was not affected by the reduced ejection fraction (HFrEF) status.
Study limitations include possible unmeasured confounding factors, the lack of consistent monitoring for all patients, a lack of information on AF recurrence, and a shorter follow-up than the original trial with substantial drop off after 2 years.
“The benefit associated with ablation appears to be more modest in practice than that reported in the CASTLE-AF trial,” noted the authors. “Future large randomized controlled trials are needed to confirm the benefit of ablation in a broad population of patients with AF and [h]eart failure.”
Noseworthy PA, Houten HKV, Gersh BJ, et al. Generalizability of the CASTLE-AF trial: catheter ablation for patients with atrial fibrillation and heart failure in routine practice. Heart Rhythm. March 2020. doi:10.1016/j.hrthm.2020.02.030