Subcutaneous Versus Transvenous Implantable Defibrillator Therapy: A Meta-Analysis of Case-Control Studies

This study aims to conduct a meta-analysis comparing efficacy and safety outcomes between subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous implantable cardioverter-defibrillator (TV-ICD).

The S-ICD was developed to minimize complications related to the conventional TV-ICD. Direct comparison of clinical outcomes between the 2 devices has been limited by varying patient characteristics and definitions of complications with no randomized trials completed comparing these systems.

Studies in the PubMed and Embase databases and secondary referencing sources were systematically reviewed. Studies meeting criteria were included in the meta-analysis. Baseline characteristics and outcome data of the S-ICD and TV-ICD groups were appraised and analyzed. A random-effects model was used to derive odds ratio (OR) with 95% confidence interval (CI).

Five studies met inclusion criteria. Baseline characteristics were similar between the S-ICD and TV-ICD groups. Fewer lead complications occurred in the S-ICD group compared to the TV-ICD group (OR: 0.13; 95% CI: 0.05 to 0.38). The infection rate was similar between the S-ICD and TV-ICD groups (OR: 0.75; 95% CI: 0.30 to 1.89). There were no differences in system or device failures between groups (OR: 1.13; 95% CI: 0.43 to 3.02). Overall, inappropriate therapy (T-wave oversensing, supraventricular tachycardia, episodes of inappropriate sensing) was similar between the 2 groups (OR: 0.87; 95% CI: 0.51 to 1.49). However, the nature of inappropriate therapy was different between the S-ICD and TV-ICD groups. Both devices appear to perform equally well with respect to appropriate shocks.

S-ICD reduced lead-related complications but was similar to TV-ICD with regard to non-lead-related complications, including inappropriate therapy. These results support the concept that S-ICD is a safe and effective alternative to TV-ICD in appropriate patients.