@ClevelandClinic – Cardiac Consult: Catheter Ablation vs Antiarrhythmic Drug Therapy in Atrial Fibrillation: CABANA – What Did We Learn?
Reporter: Aviva Lev-Ari, PhD, RN
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The international CABANA trial (Catheter Ablation versus Arrhythmia Drug Therapy for Atrial Fibrillation) was the biggest buzz at the Heart Rhythm Society Scientific Sessions earlier this year, and it’s still making waves several months later.
Cleveland Clinic is among the 120 centers participating in the trial, and electrophysiologist Bruce Lindsay, MD, is the site’s principal investigator for the study. He recently sat down with Oussama Wazni, MD, Cleveland Clinic’s Section Head of Cardiac Electrophysiology and Pacing, to discuss the CABANA trial’s findings and implications. Below is an edited transcript of their conversation.
The problem was this: About 9 percent of the patients who were supposed to get ablations never did, and it’s not clear why. The reasons could have been financial issues or patients merely changing their mind or perhaps being too sick. If it was the latter reason, that would of course bias the results. But the problem is we don’t know.
On the other side, a substantial number of patients assigned to drug therapy — 27.5 percent — crossed over and received ablation. That rate of crossover was a bit higher than anticipated.
It’s difficult to use an intention-to-treat analysis when there’s a large crossover and a lot of people don’t get the treatment they were supposed to get. Nonetheless, the study design specified an intention-to-treat analysis, which found no significant differences between the groups in the composite primary end point or any of its components. There were, however, significant reductions in hospitalization for cardiovascular problems and in time to atrial fibrillation recurrence in the ablation group, and the latter finding is consistent with results from past studies.
Because of the large number of crossovers, there was much interest in the as-treated analysis, which was prespecified as a sensitivity analysis of the primary results.
- This analysis showed a 3.9 percent absolute risk reduction — and
- a 27 percent relative reduction — in the primary end point with ablation versus drug therapy.
- That was a statistically significant effect, as was the 3.1 percent absolute reduction in all-cause death with ablation versus drug therapy.
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