Two-Year Follow-Up of the CASTLE-HTx Trial

Interview With Christian Sohns, MD

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Watch as Christian Sohns, MD, discusses his Western AF 2025 presentation on follow-up data from the CASTLE-HTx trial.

My name is Christian Sohns from the Heart and Diabetes Center, North Rhine-Westphalia, Bad Oeynhausen, Germany. I am also the principal investigator of the CASTLE-HTx trial, which we presented last year at the European Society of Cardiology Congress as a late-breaker with simultaneous publication in the New England Journal of Medicine. 

It is my pleasure this year at Western AFib to present the 2-year follow-up of this trial. This is a trial that was conducted in end-stage heart failure patients, so those patients who were referred for transplantation and transplantation evaluation and also having atrial fibrillation. These patients were randomized in a 1:1 fashion to optimal medical treatment and optimal medical treatment and catheter ablation for atrial fibrillation. We already published last year that there was a substantial difference between these 2 randomized patient groups, with a significant benefit in terms of mortality driven by all-cause mortality and cardiovascular mortality, left ventricular assist device implantation, or heart transplantation in those patients who were randomized to ablation. But it was not clear whether these effects also are sustained over time and what happens in terms of atrial fibrillation burden, left ventricular ejection fraction recovery, and other scenarios. Therefore, it was important to also report this 2-year data. 

It should also be taken into consideration that the trial was terminated early due to ethical reasons. It was no longer possible to withhold lifesaving ablation therapy from patients who were randomized to a medical therapy arm. This early termination is also important to see what happened to these patients as we initially expected 3-year follow-up for these patients. 

So, what we observed is that there were additional endpoints in the 2 treatment groups, which clearly showed us that it was the right decision to stop this trial early, first and foremost. But on the other hand, catheter ablation was very effective in having AFib burden at a stable level, 50% burden reduction after the first year, and this was sustained over time. We also saw recovery in terms of left ventricular ejection fraction in these patients. Even more important is that ablation also postponed surgical heart failure therapies. There was only one left ventricular assist device implantation, which is a potential benefit for these patients, a delay of these surgical therapies, and there was also a strong benefit in terms of cardiovascular mortality. 

So, irrespective of what kind of heart failure we discuss, whether it is reduced ejection fraction, advanced heart failure, or end-stage heart failure, ablate these patients when they have atrial fibrillation and ablate them early. One of the key messages is that it is never too late to ablate. I think when we transfer this to the patient cohort, it shows you once again that these procedures are very safe and effective, and are a benefit for the patients. Therefore, the take-home message is whenever you see a patient with heart failure and atrial fibrillation, consider ablation and perform ablation at the earliest time. Thank you.

The transcripts have been edited for clarity and length.