Equal performance of the subcutaneous and transvenous implantable cardioverter defibrillator across all age groups in the PRAETORIAN trial

Abstract Introduction The subcutaneous ICD (S-ICD) is developed to overcome lead-related complications and systemic infections, inherent to transvenous ICD (TV-ICD) therapy. In the PRAETORIAN trial the S-ICD proved to be non-inferior to the TV-ICD with regard to inappropriate shocks (IAS) and complications. However, the S-ICD is still mainly the preferred choice in young patients with a long life expectancy and therefore higher risk for lead-related complications. We aimed to evaluate the impact of age on complications and IAS between the S-ICD and TV-ICD. Methods The PRAETORIAN trial is an investigator-initiated, international, multicenter, randomized, two-arm noninferiority trial that was conducted in the United States and Europe. In total 849 patients with a class I or IIa indication for ICD therapy and no pacing indication were randomized to receive an S-ICD (N=426) or TV-ICD (N=423) and followed for a median of 49 months. We compare the occurrence of complications and IAS between increasing quartiles of age. Results Quartile 1 (Q1) consisted of 203 patients aged <55 (109 S-ICD, 94 TV-ICD), Q2 of 199 patients aged 55-62 (100 S-ICD, 99 TV-ICD), Q3 of 232 patients aged 63-69 (111 S-ICD, 121 TV-ICD) and Q4 of 215 patients aged ≥70 (106 S-ICD, 109 TV-ICD). Between the quartiles, there were no significant differences in occurrence of device-related complications (P = 0.32) or IAS (P = 0.66). In Q1, there were 15 (7.4%) complications (5 S-ICD, 10 TV-ICD) and 13 (6.4%) IAS (7 S-ICD, 6 TV-ICD), compared to 20 (10.1%) complications (7 S-ICD, 13 TV-ICD) and 17 (8.5%) IAS (9 S-ICD, 8 TV-ICD) in Q2, 22 (9.5%) complications (12 S-ICD, 10 TV-ICD) and 19 (8.2%) IAS (11 S-ICD, 8 TV-ICD) in Q3 and 18 (8.4%) complications (7 S-ICD, 11 TV-ICD) and 21 (9.8%) IAS (14 S-ICD, 7 TV-ICD) in Q4 (Figure 1.). Figure 2. shows forest plots of the hazard ratios per quartile. Conclusions The S-ICD performed equal to the TV-ICD with regard to IAS and complications between quartiles of age, making the S-ICD a good alternative across all age groups.