Among racial or ethnic minority patients enrolled in the North American cohort of the CABANA (Catheter ablation versus antiarrhythmic drug therapy for atrial fibrillation) trial, catheter ablation significantly improved major clinical outcomes compared with drug therapy. This is according to the findings of a new analysis of the trial results, published in the Journal of the American College of Cardiology (JACC).
According to the study’s authors, Kevin L Thomas (Duke Clinical Research Institute, Duke University, Durham, USA) et al, rhythm control strategies for atrial fibrillation (AF), including catheter ablation, are substantially underused in racial and ethnic minorities in North America. Therefore, the study sought to describe outcomes in the CABANA trial as a function of race and ethnicity.
CABANA was an investigator-initiated, open-label, multicentre, randomised trial in 126 centres in 10 countries of 2,204 symptomatic patients with atrial fibrillation aged ≥65 years, or <65 years with ≥one risk factors for stroke. The catheter ablation group (n=1,108) underwent pulmonary vein isolation, and the drug therapy group (n=1,096) received standard rhythm and/or rate control drugs, according to guidelines. Findings of the study were first published in the Journal of the American Medical Association (JAMA) in 2019.
The latest analysis focused only on North American participants, who were subgrouped as being a part of a racial or ethnic minority, or non-minority, with the use of National Institutes of Health definitions. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.
Thomas et al report that of 1,280 participants enrolled in CABANA in North America, 127 (9.9%) were from racial and ethnic minorities. Compared with non-minority patients, racial and ethnic minorities were younger, with median age 65.6 vs. 68.5 years, respectively, and had more symptomatic heart failure (37% vs. 22%), hypertension (92.1% vs, 76.8%, respectively), and ejection fraction <40% (20.8% vs. 7.1%).
Racial and ethnic minorities treated with ablation had a 68% relative reduction in the primary endpoint (adjusted hazard ratio [aHR]: 0.32; 95% confidence interval [CI]: 0.13‒0.78) and a 72% relative reduction in all-cause mortality (aHR: 0.28; 95% CI: 0.10‒0.79). Primary event rates in racial/ethnic minority and nonminority participants were similar in the ablation arm (four-year Kaplan-Meier event rates: 12.3% vs. 9.9%); however, racial and ethnic minorities randomised to drug therapy had a much higher event rate than nonminority participants (27.4% vs. 9.4%).
The findings led the study’s authors to conclude that among racial or ethnic minorities enrolled in the North American CABANA cohort, catheter ablation significantly improved major clinical outcomes compared with drug therapy. “These benefits,” they write, “which were not seen in non-minority participants, appear to be due to worse outcomes with drug therapy”.