Ablation Versus Drug Therapy for Atrial Fibrillation in Racial and Ethnic Minorities

Abstract

Background: Rhythm control strategies for atrial fibrillation (AF), including catheter ablation, are substantially underused in racial/ethnic minorities in North America.

Objectives: This study sought to describe outcomes in the CABANA trial as a function of race/ethnicity.

Methods: CABANA randomized 2,204 symptomatic participants with AF to ablation or drug therapy including rate and/or rhythm control drugs. Only participants in North America were included in the present analysis, and participants were subgrouped as racial/ethnic minority or nonminority with the use of National Institutes of Health definitions. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.

Results: Of 1,280 participants enrolled in CABANA in North America, 127 (9.9%) were racial and ethnic minorities. Compared with nonminorities, racial and ethnic minorities were younger with median age 65.6 versus 68.5 years, respectively, and had more symptomatic heart failure (37.0% vs 22.0%), hypertension (92.1% vs 76.8%, respectively), and ejection fraction <40% (20.8% vs 7.1%). Racial/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 (4-year Kaplan-Meier event rates 12.3% vs 9.9%); however, racial and ethnic minorities randomized to drug therapy had a much higher event rate than nonminority participants (27.4% vs. 9.4%).

Conclusion: 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, which were not seen in nonminority participants, appear to be due to worse outcomes with drug therapy. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial [CABANA]; NCT00911508).

Keywords: atrial fibrillation; catheter ablation; minority race; outcomes; randomized trials.

Conflict of interest statement

Funding Support and Author Disclosures This work was supported by the National Institutes of Health (U01HL89709, U01HL089786, U01HL089907, and U01HL089645), St. Jude Medical Foundation and Corporation, Biosense Webster, Medtronic, and Boston Scientific Corporation. The content of this paper does not necessarily represent the views of the National Heart, Lung, and Blood Institute or the Department of Health and Human Services. Dr. Thomas has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), Patient-Centered Outcomes Research Institute, and American Heart Association; and has received consulting fees from Sanofi, Boehringer Ingelheim, Janssen, Bristol Myers Squibb, and Medtronic during the conduct of the study. Dr. Al-Khalidi has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health) and the Mayo Clinic during the conduct of the study. Dr. Monahan has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), St. Jude Foundation and Corporation, Biosense Webster, Medtronic, and Boston Scientific during the conduct of the study; has consulted without compensation from Biosense Webster; and has received personal fees from Thermedical outside the submitted work. Dr. Bahnson has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health) and the Mayo Clinic for conduct of the study; has received grants from Boston Scientific, St. Jude Medical Corporation, Biosense Webster, and Medtronic; and has received compensation for consulting from Cardiofocus and Ventrix during the conduct of the study but outside of the submitted work. Dr. Poole has received grants from ATriCure outside the submitted work. Dr. Mark has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), the Mayo Clinic during the conduct of the study; and has received grants from Merck and HeartFlow outside the submitted work. Dr. Packer in the past 12 months has provided consulting services for Biosense Webster, Inc., Boston Scientific, CyberHeart, Medtronic, Inc., nContact, Sanofi, St. Jude Medical, and Toray Industries but has received no personal compensation for these consulting activities; has received grants from Abbott, Biosense Webster, Boston Scientific, CardioFocus, Medtronic, St. Jude Medical, CardioInsight, National Institutes of Health, Siemens, Thermedical, Endosense, Robertson Foundation, and Hansen Medical; has served on the advisory board without compensation for Abbott, Biosense Webster, Boston Scientific, CardioFocus, Medtronic, St. Jude Medical, Spectrum Dynamics, Siemens, Thermedical, Johnson & Johnson, and SigNum Preemptive Healthcare; has received speaking fees and honoraria from Biotronik and MediaSphere Medical; has received royalties from Wiley & Sons, Oxford, and St. Jude Medical; has joint equity with the Mayo Clinic in a privately held company, External Beam Ablation Medical Devices, outside the submitted work; and has received research funding from the NIH, Medtronic, Inc., Cryo Cath, Siemens AG, EP Limited, Minnesota Partnership for Biotechnology and Medical Genomics/University of Minnesota, Biosense Webster, Inc., and Boston Scientific. Mayo Clinic and Drs. Packer and Robb have a financial interest in mapping technology that may have been used at some of the 10 centers participating in this pilot research; in accordance with the Bayh-Dole Act, this technology has been licensed to St. Jude Medical, and Mayo Clinic and Drs. Packer and Robb received annual royalties >$10,000, the federal threshold for significant financial interest. Dr. Silverstein has reported that he has no relationships relevant to the contents of this paper to disclose.

Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1:. CONSORT Diagram for the Racial/Ethnic Minority Subgroup Analysis in CABANA.

This diagram shows the derivation of the cohort for the CABANA subgroup analysis examining outcomes by racial and ethnic minority status in patients enrolled in North America.

Figure 2:. Kaplan-Meier Estimates of Total Mortality Among Racial and Ethnic Minorities.

Kaplan-Meier estimates of the cumulative risk of death by intention-to-treat analysis. In the non-minority group, the outcomes do not differ between treatment groups. In the racial and ethnic minority subgroup, patients randomized to ablation had a far lower risk of death out to 4 years compared to drug therapy alone. CI=confidence interval.

Figure 3:. First Recurrence of Atrial Fibrillation Post Blanking Period Among Racial and Ethnic Minorities.

Cumulative incidence estimates using death as a competing risk were derived using Fine-Gray competing risks methodology. Cumulative freedom from recurrence of atrial fibrillation following a 90-day post-treatment blanking period is shown by randomized treatment group for the 72 racial or ethnic minority patients enrolled in North America who used the CABANA Box electrocardiogram event recorders. Patients randomized to ablation were at lower risk of recurrence of atrial fibrillation through 48 months of follow-up.

Figure 4:. Atrial Fibrillation Burden by Time and Randomization Assignment Who Used the CABANA-Box.

The percentage of atrial fibrillation burden is shown according to randomized treatment groups as assessed at each of the 6-month Holter recording timepoints for (A) Racial and ethnic minority participants in North America and (B) Non-minority participants in North America.

Figure 4:. Atrial Fibrillation Burden by Time and Randomization Assignment Who Used the CABANA-Box.

The percentage of atrial fibrillation burden is shown according to randomized treatment groups as assessed at each of the 6-month Holter recording timepoints for (A) Racial and ethnic minority participants in North America and (B) Non-minority participants in North America.

Central Illustration:. Kaplan-Meier Estimates of the Primary Composite Endpoint Among Racial and Ethnic Minorities and Non-minorities by Randomized Treatment in CABANA.

Kaplan-Meier estimates of the cumulative risk of having a primary endpoint event by intention-to-treat analysis. In the non-minority group, the outcomes do not differ significantly between treatment groups. In the racial and ethnic minority subgroup, patients randomized to ablation have a lower risk of having a primary endpoint event out to 4 years compared to drug therapy alone. CI=confidence interval.