Catheter ablation boosts outcomes in patients with advanced HF

Catheter ablation boosts outcomes in patients with advanced heart failure (HF) who are being considered for heart transplantation or left ventricular assist device (LVAD) implantation in the CASTLE-HTx trial presented at ESC 2023.

Adding ablation to guideline-directed medical therapy (GDMT) significantly reduced a composite of all-cause death, LVAD implantation, or urgent heart transplantation through a median follow-up of 18 months (hazard ratio [HR], 0.24), reported lead study author Dr Christian Sohns from the Heart and Diabetes Center North Rhine-Westphalia in Bad Oeynhausen, Germany.

“The benefit was driven by significant reductions in both death and LVAD implantation, with a favourable, albeit not significant, trend in heart transplantation,” he added.

Potentially practice-changing

“This suggests that AF ablation should be considered as part of the standard treatment options in patients with advanced HF,” commented co-study author Dr Phillip Sommer, Director of the Clinic for Electrophysiology and Professor at the Heart and Diabetes Center North Rhine-Westphalia, University Clinic of Bochum, Bad Oeynhausen, Germany, during a press conference.

“AF ablation has beneficial effects on mortality during the waiting time for patients planning to undergo transplantation … it prolongs the time span until surgical interventions will be necessary,” he added. “We think the quality of the data is strong enough to affect guidelines.”

Patients with end-stage HF have traditionally been excluded from prior studies. Hence, there have been questions about whether ablation is feasible, can reduce AF burden, or can improve LV function and clinical outcomes in more advanced HF.

Looking for answers

CASTLE-HTx was designed to address those questions. Patients (n=194) in the trial had end-stage HF and were referred to a German centre for evaluation for heart transplantation or LVAD implantation. The mean age of the patients was 63.5 years. Eighty-one percent were men. They had at least NYHA class II symptoms, an LVEF of ≤35 percent, and impaired functional capacity based on the 6-minute walk test. All had an implanted cardiac device that allowed for continuous rhythm monitoring.

Patients were randomized to AF ablation plus GDMT or GDMT alone and followed for a median of 18 months. The trial was stopped early for efficacy following a recommendation from the data and safety monitoring board. Ultimately, ablation was performed in 84 percent of patients initially assigned to undergo the procedure and 16 percent of patients in the GDMT alone group. [N Engl J Med 2023;doi:10.1056/NEJMoa2306037]

Better outcomes with ablation

After a median follow-up of 18 months, the primary composite endpoint of all-cause death, LVAD implantation, or urgent heart transplantation occurred in 8 percent of patients in the ablation group and 30 percent of those in the control group (p<0.001).

Reductions in all cause-death occurred in 6 percent of the ablation group vs 20 percent in the control group (HR, 0.29). Additionally, urgent heart transplantation was performed in 1 percent of the ablation group vs 6 percent in the control group (HR, 0.15). LVAD implantation was 1 percent vs 10 percent, respectively (HR, 0.09). All but two of the deaths were attributed to cardiovascular causes.

“What we found as meaningful were the greater improvement in left ventricular ejection fraction (LVEF) with the ablation group (7.8 percent vs 1.4 percent with control) by 12 months and the greater drop in AF burden (31.4 percent vs 8.6 percent, respectively),” said Sohns.

Procedure-related complications occurred in three patients in the ablation group and one in the control group. All were related to the vascular access site.

Experts were quick to note some limitations of the trial, including its open-label design, the relatively small sample size (194 patients), and the fact that it was conducted at a single centre. Despite these limitations, the discussant for the trial Dr Finn Gustafsson from the Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark said CASTLE-HTx showed that this group of patients “should be considered for ablation as it may prevent the need for heart transplantation or LVAD implantation. And that would be a huge achievement.”