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PRAETORIAN Study shows in a general ICD population that treatment with subcutaneous ICD is equally effective and safe as transvenous ICD with less lead complications

The subcutaneous implantable defibrillator (ICD) offers comparable performance in treating patients at risk of sudden cardiac death as the traditional transvenous ICD that has a lead in the heart, but gives less lead related complications. This is the outcome of the international PRAETORIAN trial: ICD-related complications were seen in 15.1% of patients with a subcutaneous ICD (S-ICD) versus 15.7% patients with a transvenous ICD (TV-ICD) after a median follow up of 4 years. Lead complications occurred in 6.6% of the patients with a TV-ICD, compared to 1.4% of the patients with a subcutaneous device. The PRAETORIAN trial is the first prospective randomized study to compare the two ICD types and the first to study the use of the S-ICD in a generalized ICD population. With this outcome it is now possible to make a better assessment of the preferred device for each patient with an ICD indication. The study was conducted in 39 centers in the Netherlands, Germany, Denmark, United Kingdom and the United States. Results were presented at HRS 2020 Science and are published in the prestigious journal The New England Journal of Medicine.

“For the treatment of sudden cardiac death, ICDs are a well-established treatment option, however, there are certain problems associated with transvenous leads, “ explains study Principal Investigator Dr, Reinoud E. Knops, M.D., PhD, from the Cardiology Department of the AMC, Amsterdam UMC, in the Netherlands, who initiated the study. “The S-ICD has no lead in the heart, but instead this lead is implanted subcutaneously. As we expected, the PRAETORIAN trial shows that the S-ICD is just as safe and effective as the TV-ICD and at the same time gives less lead complications, which have risks of their own.”

The PRAETORIAN trial is the first randomized study to head-to-head compare the TV-ICD and S-ICD. ‘In addition, earlier studies with the S-ICD included selected patient populations in whom physicians anticipated more problems with the TV-ICD”, Knops said. “In PRAETORIAN we have included all patients who are eligible to receive an S-ICD such that the PRAETORIAN patient population more accurately matches the actual ICD population. We are therefore able to make a better comparison between the two ICDs than was possible thus far.”

In this study, 849 participants with a class I or IIa indication for ICD therapy according to the prevailing ACC/AHA/ESC guidelines were included. As the subcutaneous ICD is currently not able to give pacing therapy, only patients who did not require bradypacing, resynchronization therapy or anti-tachycardia pacing were included in the study. Participants were randomly assigned to receive either a transvenous or subcutaneous ICD and followed for a median of 4 years. The main objectives of the trial were to compare the rates of all complications and inappropriate shocks, which are shocks given for anything else than ventricular tachycardia or ventricular fibrillation. Device-related complications occurred in 31 patients with a S-ICD (5.9%) and in 44 patients with a transvenous device (9.8%). Inappropriate shocks occurred in 41 patients with an S-ICD (9.7%) and in 29 patients with a TV-ICD (7.3%). There was no difference in mortality.

“The study shows that there is a difference in type of complications between the devices. Patients with an S-ICD have less complications that require intervention than patients with a TV-ICD, but get more inappropriate shocks. It is however important to realize that this study began in 2011 when the S-ICD was still relatively new. Since then several updates have been made to prevent inappropriate shocks,” continued Knops. Earlier studies have shown that lead-related complications of the TV-ICD increase over time, especially after more than 4 years. To compare the treatments on the longer term, PRAETORIAN follow up is continued for another 4 years. Knops concludes: “It will be interesting to see what happens if we follow these patients longer. However, given the current results it is already important to always consider the S-ICD for each patient in need of an ICD without pacing indication.”

This study was funded by a research grant from the Boston Scientific Investigator-Sponsored Research Program. The company had no role in the design, conduct and analysis of the study.