Background: The PRAETORIAN trial was designed to demonstrate non-inferiority of the S-ICD versus TV-ICD at a median follow-up duration of 48 months for the composite primary endpoint of device-related complications and inappropriate shocks. Since the introduction of the S-ICD new algorithms have been introduced resulting in a decreased incidence of inappropriate shocks, making these less important in the evaluation of S-ICD treatment. However, the expected benefit of the subcutaneous position of the S-ICD with regards to device-related complications can only be demonstrated during a longer follow-up period, as transvenous lead-related complications occur during long term follow-up.
The complication rate of the S-ICD is expected to stabilize after initial acute complications. Acute complications such as lead dislodgement are clinically less severe as these can often be easily resolved. In contrast, chronic (lead) complications that are seen in the TV-ICD therapy impose a greater risk for patients as they often involve systemic infection with endocarditis and/or extraction in a tertiary extraction center with a significant risk of morbidity and/or mortality. The PRAETORIAN trial population provides a unique opportunity to observe long-term performance of the S-ICD, as it is highly unlikely that a new trial that randomizes between S-ICD and TV-ICD will be performed with current available evidence about benefits of the S-ICD in certain patient populations. Therefore, all patients enrolled in the PRAETORIAN trial will be approached for an extended follow-up duration of 48 additional months.
Objectives: The primary objective is to determine whether the S-ICD is superior to the TV-ICD with respect to acute and chronic device-related complications.
Study design: The study design of the sub-study PRAETORIAN XL cannot be considered a continuation of the original randomized trial. Instead, this extension must be considered as an observational study of one of the pre-defined secondary endpoints with an extended follow-up duration. The follow-up duration will be extended with an additional 48 months. Patients will be asked for written informed consent prior to completion of PRAETORIAN.
Primary endpoint: The primary composite endpoint consists of acute and chronic device-related complications.
Patient selection: All patients enrolled in PRAETORIAN trial were eligible for the sub-study and were asked for written informed consent. Consenting started prior to the end of the ongoing trial, to prevent loss of follow-up or bias in patient selection. If there was no in-hospital follow-up visit planned before completion of the initial follow-up, patients were informed about the extended follow-up by telephone and the informed consent form was sent to them by mail. For patients who have not consented before completion of PRAETORIAN, data was collected retrospectively once the patient gave consent.