A new analysis of the CASTLE-AF (Catheter Ablation for Atrial Fibrillation with Heart Failure) trial has found that catheter ablation for AFib remains effective in a much larger group of heart failure patients, cementing evidence first presented in early 2018.
Peter Noseworthy, MD, a Mayo Clinic cardiologist, and Xiaoxi Yao, PhD, a Mayo Clinic health services researcher, launched the updated study as an adjunct to its predecessor. CASTLE-AF found a 38% reduction in risk of death or hospitalization for worsening HF in patients with both HF and AFib, but the sample size for the study was small, clocking in at just 363 participants.
“Randomized clinical trials are the gold standard for evaluating new medical treatments or procedures,” Yao said in a statement. “However, often their results are not necessarily applicable across a more heterogeneous group of people. Sometimes results cannot be replicated or are simply not as striking when interventions are tested across a broader population.”
Noseworthy, Yao and their team used the OptumLabs Data Warehouse, a longitudinal, real-world data asset with de-identified administrative claims and EHR data, to determine how CASTLE-AF would have rolled out in a larger group of people—namely one comprised of 289,831 patients with both HF and AFib. That’s nearly 800 times the size of the original CASTLE-AF study.
The authors found that less than 8% of the larger group would have been fully eligible to participate in the CASTLE-AF trial, though just 15.5% would have met exclusion criteria. Among patients who would have been eligible to participate, the team estimated an 18% reduction in risk of death or hospitalization for worsening HF with ablation.
Noseworthy, Yao et al. did note that their results were much more modest than those of the CASTLE-AF trial. They also said people in the current study who received ablation and met exclusion criteria for the clinical trial didn’t reduce their risk of death but rather increased their likelihood of HF-related hospitalization.
“CASTLE-AF had very dramatic results—a nearly 40% mortality benefit of ablation in this population,” Noseworthy said in the statement. “We needed to see how this played out in everyday practice.
“Our study is especially important because it provides complementary evidence in a case where very few clinical trials have been conducted. In addition, a large observational study provides a more realistic picture of treatment effects for our everyday patients.”