Device-related Complications in Transvenous Versus Subcutaneous Defibrillator Therapy During Long-term Follow-up: the PRAETORIAN-XL Trial

Background: The PRAETORIAN trial investigated the efficacy and safety of the subcutaneous implantable cardioverter-defibrillator (S-ICD) compared with transvenous ICD (TV-ICD) and showed non-inferiority of the S-ICD with regard to the composite endpoint of device-related complications and inappropriate shocks (IAS) after 49.1 months. Complications associated with transvenous leads are expected to occur after longer follow-up. The PRAETORIAN-XL trial aims to investigate whether the S-ICD is superior to the TV-ICD with respect to device-related complications at 8-year follow-up. Methods: The PRAETORIAN trial randomized patients with a class I or IIa indication for ICD therapy without the need for pacing to either S-ICD or TV-ICD among 39 centers in the US and Europe between March 2011 and January 2017. The follow-up was extended after 49.1 months with an additional four years, for the PRAETORIAN-XL trial. The primary endpoint was the composite of all device-related complications. Complications could be related or unrelated to the lead, and minor or major, with major complications being those requiring an invasive intervention. Endpoints were analyzed according to the modified intention-to-treat principle using a Fine-Gray subdistribution hazards model to account for competing risks. An as-treated analysis was performed using a Cox proportional hazards model with device type as time-dependent variable. Results: Patients were randomized to S-ICD (N=426) and TV-ICD (N=423). Twenty-one percent of the S-ICD group versus 18% of the TV-ICD group was female. The median age at implantation was 63 (IQR 54-69) years for the S-ICD and 64 (IQR 56-69) years for the TV-ICD. After a median follow-up of 87.5 months, all device-related complications (major and minor combined) were not significantly different in the modified intention-to-treat analysis (sHR 0.73 (95%CI 0.48-1.12); P=0.15). However, TV-ICD patients more often had a major complication or lead-related complication (P=0.03 and P<0.001 respectively). Moreover, the as-treated analysis showed significantly more complications in patients with a TV-ICD compared with an S-ICD (HR 0.64 (95%CI 0.41-0.99); P=0.047). Conclusions: The PRAETORIAN-XL trial demonstrated that there was no significant difference between the S-ICD and TV-ICD in all device-related complications during long-term follow-up. However, the TV-ICD carries a higher risk of major and lead-related complications compared with S-ICD therapy. The S-ICD should therefore be considered in all patients without a pacing indication who are evaluated for ICD therapy.