Subcutaneous versus transvenous implantable defibrillator: An updated meta-analysis

BACKGROUND Implantable cardioverter-defibrillator (ICD) placement is a well-established therapy for prevention of sudden cardiac death. The subcutaneous implantable cardioverterdefibrillator (S-ICD) was specifically designed to overcome some of the complications related to the transvenous implantable cardioverter-defibrillator (TV-ICD), such as lead complications and systemic infections. Evidence on the comparison of S-ICD vs TV-ICD are limited. OBJECTIVE The purpose of this study was to conduct an updated meta-analysis comparing S-ICD vs TV-ICD. METHODS Electronic databases were searched for studies directly comparing clinical outcomes and complications between S-ICD and TV-ICD. The primary outcome was the composite of clinically relevant complications (lead, pocket, major procedural complications; device-related infections) and inappropriate shocks. Secondary outcomes included death and the individual components of the primary outcome. RESULTS Thirteen studies comprising 9073 patients were included in the analysis. Mean left ventricular ejection fraction was 40% +/- 10%; 30% of patients were female; and 73% had an ICD implanted for primary prevention. There was no statistically significant difference in the risk of the primary outcome between S-ICD and TV-ICD (odds ratio [OR] 0.80; 95% confidence interval [CI] 0.53-1.19). Patients with S-ICD had lower risk of lead complications (OR 0.14; 95% CI 0.06-0.29; P <.00001) and major procedural complications (OR 0.18; 95% CI 0.06-0.57; P = .003) but higher risk of pocket complications (OR 2.18; 95% CI 1.30-3.66; P = .003) compared to those with TV-ICD. No significant differences were found for the other outcomes. CONCLUSION In patients with an indication for ICD without the need for pacing, TV-ICD and S-ICD are overall comparable in terms of the composite of clinically relevant device-related complications and inappropriate shock.