The results of the PRAETORIAN-XL were presented as a late breaking trial at the Heart Rhythm 2025 conference in San Diego. In the study, 849 patients in 39 hospitals in Europe and the US were randomized between two types of ICD; the subcutaneous and the transvenous ICD. These patients were followed for more than 7 years, which showed a significantly lower risk in severe complications for patients with a subcutaneous ICD. The study was fully executed by Amsterdam UMC.
First prospective randomized study
At the start of the study, the use of transvenous ICDs were well-established as a treatment for sudden cardiac death. However, the transvenous leads were associated with certain complications. With the lead implanted subcutaneously, the subcutaneous ICD provides a possible alternative. The PRAETORIAN study was started at Amsterdam UMC as the first prospective randomized study two compare these two different ICD types. In 2020, the results after 4 years of follow-up were presented and showed a comparable performance of the subcutaneous ICD in comparison to the transvenous ICD.
Dr. Louise Olde Nordkamp, Prof. dr. Reinoud Knops (principal investigators) and drs. Jolien de Veld (MD/PhD candidate)
Long-term therapy can lead to complications in the longer term
The follow-up period was further extended to a total period of more than 7 years. ICD therapy is a long-term therapy that can continue for years, sometimes even lifelong. Complications can arise at different times during the treatment, but it is known that due to the long-term strain on the leads, among other things, many complications arise in the longer term. The initial PRAETORIAN study had an average follow-up time of 4 years, which meant that these long-term complications could not be fully included. ‘We therefore felt that it was desirable to follow up this group of patients for a longer period’ says Reinoud Knops.
An important step in adjusting treatment guidelines
‘This is the longest-followed group of patients randomized to a subcutaneous or transvenous ICD, providing valuable insights into the long-term effects and safety of both ICDs’ according to Louise Olde Nordkamp. It appears that there was no difference in complication rate when looking at major and minor complications, but especially major complications, which were complications in need of an invasive intervention, were more frequent in patients receiving transvenous ICDs. The results of the study will therefore make an important contribution to adjusting guidelines for the treatment of people with a high risk of life-threatening cardiac arrhythmias. The subcutaneous ICD has been used more frequently in recent years, but current guidelines still recommend considering subcutaneous ICD as an alternative to the transvenous ICD. PRAETORIAN-XL shows that the subcutaneous ICD is truly equivalent to the transvenous ICD and is even better in the long term in preventing serious complications or lead-related complications. Therefore, the subcutaneous ICD should be strongly considered in all patients who are eligible for ICD therapy.
randomized to a subcutaneous or transvenous ICD, providing valuable insights into the long-term effects and safety of both ICDs’
Insight in specific patient populations in the future
The study has now been completed and the results were be presented at the at the Heart Rhythm 2025 conference in San Diego, which was held from April 24 until 27. ‘What makes this study unique is its duration of 12.5 years, a remarkable length for research of this kind’ says Jolien de Veld. Although the main analysis is now complete, there are plans to perform various subanalyses, such as complication-outcome differences between men and women, or between older and younger patients. ‘In this way, we try to gain more insight into the advantages and disadvantages of both types of ICDs for specific patient populations.’