Subcutaneous Versus Transvenous Implantable Defibrillator Therapy: A Systematic Review and Meta-Analysis of Randomized Trials and Propensity Score-Matched Studies.

Background Subcutaneous implantable cardioverter-defibrillators (S-ICDs) have been of great interest as an alternative to transvenous implantable cardioverter-defibrillators (TV-ICDs). No meta-analyses synthesizing data from high-quality studies have yet been published. Methods and Results An electronic literature search was conducted to retrieve randomized controlled trials or propensity score-matched studies comparing S-ICD against TV-ICD in patients with an implantable cardioverter-defibrillator indication. The primary outcomes were device-related complications and lead-related complications. Secondary outcomes were inappropriate shocks, appropriate shock, all-cause mortality, and infection. All outcomes were pooled under random-effects meta-analyses and reported as risk ratios (RRs) and 95% CIs. Kaplan-Meier curves of device-related complications were digitized to retrieve individual patient data and pooled under a 1-stage meta-analysis using Cox models to determine hazard ratios (HRs) of patients undergoing S-ICD versus TV-ICD. A total of 5 studies (2387 patients) were retrieved. S-ICD had a similar rate of device-related complications compared with TV-ICD (RR, 0.59 [95% CI, 0.33-1.04];