CASTLE-HTx: Catheter Ablation Improves Outcomes in Heart Failure with AFib

Christian Sohns, MD
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Results of the CASTLE-HTx trial indicate undergoing catheter ablation was linked to a significantly lower risk of death, urgent transplantation, or left ventricular assist device (LVAD) implantation compared with medical therapy in patients with end-stage heart failure and atrial fibrillation.

Presented at the European Society of Cardiology (ESC) Congress 2023, results of the study, which was stopped for efficacy by the data and safety monitoring board 1 year after randomization was completed, suggest undergoing catheter ablation was associated with a 76% reduction in risk of the trial’s primary composite endpoint relative to medical therapy alone.¹

“Comparing atrial fibrillation ablation with medical therapy in patients with end-stage heart failure, ablation was associated with lower rates of death, urgent heart transplantation or LVAD implantation, along with a reduction in atrial fibrillation burden and improved LVEF,” said Christian Sohns, MD, of the Heart and Diabetes Center North Rhine-Westphalia.² “Of note, listing for transplantation should not be postponed given the long waiting times and high waitlist mortality.”

A single-center, open-label, investigator-initiated, superiority, randomized clinical trial, CASTLE-HTx was launched with the intent of exploring the safety and efficacy of catheter ablation in patients with end-stage heart failure and symptomatic atrial fibrillation who were referred to a single center in the Netherlands for evaluation for heart transplantation or implantation of a left ventricular assist device. In total, 97 patients were assigned to the ablation group and 97 were assigned to the medical therapy group.¹

The ablation group had a mean age of 62 (Standard deviation [SD], 12) years and 88% were male. At baseline, the group had a mean BMI of 28 (SD, 4) kg/m2, 88% had NYHA Class II-III symptoms, the mean ejection fraction was 29% (SD, 6%), and 56% had persistent atrial fibrillation. The medical therapy group had a mean age of 65 (SD, 10) years and 74% were male. At baseline, then group had a mean BMI of 28 (SD, 5) kg/m2, 87% had NYHA Class II-III symptoms, the mean ejection fraction was 25% (SD, 6%), and 56% had persistent atrial fibrillation.¹

The primary endpoint of interest for the trial was a composite of death from any cause, implantation of an LVAD, or urgent heart transplantation. Secondary endpoints of interest for the trial included the components of the primary endpoint.¹

Upon analysis, results indicated catheter ablation was performed in 84% of the ablation group and 16% of the medical therapy-only group. During a median follow-up of 18 (Interquartile range, 14.6-22.6) months, primary endpoint events were identified among 8% of the ablation group and 30% of the medical therapy-only group (Hazard ratio [HR], 0.24; 95% confidence interval [CI], 0.11-0.52; P < .001).¹

Analysis of secondary endpoints revealed all-cause mortality occurred among 6% of the ablation group compared to 20% of the medical therapy group (HR, 0.29; 95% CI, 0.12-0.72). Additionally, urgent heart transplantation was performed in 1% of the ablation group and in 6% in the medical-therapy group (cause-specific HR, 0.15; 95% CI, 0.02-1.25). Investigators also pointed out 56% of the ablation group were free of primary endpoint events and not in persistent atrial fibrillation at 12 months compared with 9% of the medical therapy group.¹

“We found that catheter ablation of atrial fibrillation plus medical therapy in patients with end-stage heart failure who were referred for transplantation evaluation was associated with a lower likelihood of a composite of death from any cause, implantation of a left ventricular assist device, or urgent heart transplantation than medical therapy alone,” investigators wrote.¹ “Fewer deaths from any cause and implantations of a left ventricular assist device occurred among the patients who received catheter ablation than among those who received medical therapy alone.”

References:

1. Sohns C, Fox H, Marrouche NF, et al. Catheter Ablation in End-Stage Heart Failure with Atrial Fibrillation [published online ahead of print, 2023 Aug 27]. N Engl J Med. 2023;10.1056/NEJMoa2306037. doi:10.1056/NEJMoa2306037
2. European Society of Cardiology. Atrial fibrillation ablation improves outcomes in patients with end-stage heart failure. European Society of Cardiology. August 27, 2023. Accessed September 1, 2023. https://www.escardio.org/The-ESC/Press-Office/Press-releases/Atrial-fibrillation-ablation-improves-outcomes-in-patients-with-end-stage-heart-failure.