touchCARDIO coverage of data from PRAETORIAN XL presented at Heart Rhythm 2025:

In this interview, Dr Louise Olde Nordkamp, Amsterdam University Medical Center, Amsterdam, Netherlands, discusses the long-term findings of the PRAETORIAN XL trial—a follow-up study comparing transvenous and subcutaneous implantable cardioverter-defibrillators (ICDs). Building on the original PRAETORIAN trial, this extended 8-year analysis evaluated device-related complications and confirmed that subcutaneous ICDs carry fewer major and lead-related complications. Dr Olde Nordkamp highlights the clinical relevance of these results, supporting broader consideration of subcutaneous ICDs in patients without pacing indications.

Transcript:

Introduction

I’m Dr Olde Nordkamp, and I’m working at the Amsterdam University Medical Center as a device cardiologist.

What is the state of play currently in transvenous versus subcutaneous defibrillator therapy?

So, implantable cardiac defibrillators [ICDs] are a safe and effective therapy for the prevention of sudden cardiac death. For decades, conventional ICDs, transvenous ICDs, were the standard of care, but these devices are associated with a risk of complications related to the transvenous lead placements, such as infection, pneumothorax and lead dysfunction.

Subcutaneous ICDs have a totally extravascular design and were developed to overcome the risk of these lead-related complications.

So that’s the current state of play, what we have in our ICD therapy at this moment.

What was the background and rationale for the PRAETORIAN XL trial?

So, to compare the transvenous ICD with the subcutaneous ICD, the multicenter, randomized PRAETORIAN trial was conducted. The trial showed that the subcutaneous ICD was non-inferior to transvenous ICDs with regard to the composite primary endpoint of device-related complications and inappropriate shocks.

Subsequently, a secondary analysis of the PRAETORIAN trial showed that the complications in the transvenous ICD arm were more severe, as they required more often invasive interventions.

Early concerns of the increased number of inappropriate shocks resulting from oversensing since the introduction of the subcutaneous ICD have been mitigated by optimization of programming and new software algorithms. And complications with transvenous leads, especially lead failure and lead infection, generally continue to rise during long term follow-up.

And to compare the subcutaneous ICD with the transvenous ICD with regard to device-related complications over time, the follow-up of the participants of the PRAETORIAN trial was extended for a total of almost 8 years, and this was the Praetorian XL trial.

What were the aims and design of the trial?

Primary aim of the study of the PRAETORIAN XL trial was to determine whether the subcutaneous ICD was superior to the transvenous ICD regarding device-related complications during long term follow-up.

And to investigate this, we extended the follow-up of the PRAETORIAN trial to a total of 8 years, almost 8 years.

In the PRAETORIAN trial, 849 patients with a class 1 or 2a indication for ICD therapy without the need for pacing were randomized to either subcutaneous or transvenous ICD therapy.

Now in the PRAETORIAN trial, the PRAETORIAN XL trial, these patients were followed for a median of almost 8 years. The primary endpoint for PRAETORIAN XL was all major and minor device-related complications, and secondary endpoints were major complications, lead-related complications and mortality.

What were the key findings?

So in a conventional ICD population with a mean age of 63 years, with 20% of patients being female and 2/3 of patients having an ischaemic cardiomyopathy, the cumulative incidence of both major and minor device-related complications was 8% in the subcutaneous ICD group and 11.6% in the transvenous ICD group. And this was not a significant difference.

However, the cumulative incidence of major device-related complications, defined as complications in which there was an invasive intervention needed, this was significantly higher in the transvenous ICD group with 5.7% in the subcutaneous ICD group and 10.2% in the transvenous ICD group.

Also, at 8 years, the cumulative incidence of lead-related complications was significantly higher in the transvenous ICD group with 2.4% in the subcutaneous ICD group and 8.3% in the transvenous ICD group. This is in hazard ratio of 0.3. Because many patients crossed over to the other arm, during the study, we did an additional as-treated analysis in which the patients were analyzed according to the device type they actually had at the moment of complications.

And this analysis also showed that there were significantly less complication in the patients who had a subcutaneous ICD.

At last, there was no difference in mortality between arms.

What do you think will be the impact on clinical practice?

So the PRAETORIAN XL trial demonstrated that during a long-term follow-up, there were no significant differences between the subcutaneous and the transvenous ICD in all device-related complications.

However, the subcutaneous ICD carries a significantly lower risk of major and lead-related complications compared to transvenous ICD therapy.

And, therefore, the subcutaneous ICD should be strongly considered in all patients without a pacing indication who are evaluated for ICD therapy.

References:

Disclosures: Louise Olde Nordkamp has been a consultant for Boston Scientific, Abbott and Medtronic.

This content has been developed independently by Touch Medical Media for touchCARDIO and is not affiliated with Heart Rhythm 2025. Unapproved products or unapproved uses of approved products may be discussed by the faculty; these situations may reflect the approval status in one or more jurisdictions. No endorsement of unapproved products or unapproved uses is either made or implied by mention of these products or uses by Touch Medical Media or any sponsor. Views expressed are the speaker’s own and do not necessarily reflect the views of Touch Medical Media.

Interviewer/Editor: Heather Hall, Managing Editor

Cite: Olde Nordkamp L. PRAETORIAN XL: Long-Term Outcomes of Subcutaneous versus Transvenous ICD Therapy. touchCARDIO, July 18 2025.

Click here for more content on interventional cardiology and for further congress highlights visit here.

SIGN UP to touchCARDIO!

Register Register

Join our global community today for access to thousands of peer-reviewed articles, expert insights, and learn-on-the-go education across 150+ specialties, plus concise email updates and newsletters so you never miss out.