Comparative Assessment of Transvenous versus Subcutaneous Implantable Cardioverter-defibrillator Therapy Outcomes: An Updated Systematic Review and Meta-analysis

Background: Subcutaneous (S-ICD) and transvenous (TV-ICD) implantable cardioverter-defibrillator devices effectively reduce the incidence of sudden cardiac death in patients at a high risk of ventricular arrhythmias. This study aimed to evaluate the safe replacement of TV-ICD with S-ICD based on updated recent evidence. Methods: We systematically searched EMBASE, JSTOR, PubMed/MEDLINE, and Cochrane Library on 30 July 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: We identified 26 studies that examined 7542 (58.27%) patients with S-ICD and 5400 (41.72%) with TV-ICD. The findings indicated that, compared to patients with TV-ICD, patients with S-ICD had a lower incidence of defibrillation lead failure (odds ratio [OR], 0.12; 95% confidence interval [CI], 0.01–0.98; p = 0.05), lead displacement or fracture (OR, 0.25; 95% CI, 0.12–0.86; p = 0.0003), pneumothorax and/or hemothorax (OR: 0.22, 95% CI 0.05, 0.97, p = 0.05), device failure (OR: 0.70, 95% CI 0.51, 0.95, p = 0.02), all-cause mortality (OR: 0.44 [95% CI 0.32, 0.60], p < 0.001), and lead erosion (OR: 0.01, 95% CI 0.00, 0.05, p < 0.001). Patients with TV-ICD had a higher incidence of pocket complications than patients with S-ICD (OR, 2.13; 95% CI, 1.23–3.69; p = 0.007) and a higher but insignificant incidence of inappropriate sensing (OR, 3.53; 95% CI, 0.97–12.86; p = 0.06). Conclusions: The S-ICD algorithm was safer and more effective than the TV-ICD system as it minimized the incidence of pocket complications, lead displacement or fracture, inappropriate sensing, defibrillation lead failure, pneumothorax/hemothorax, device failure, lead erosion, and all-cause mortality. Future studies should explore the scope of integrating novel algorithms with the current S-ICD systems to improve cardiovascular outcomes.