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

Abstract

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]; P =0.070), but a significantly lower lead‐related complication rate (RR, 0.14 [95% CI, 0.07–0.29]; P <0.0001). The individual patient data–based 1‐stage stratified Cox model for device‐related complications across 4 studies yielded no significant difference (shared‐frailty HR, 0.82 [95% CI, 0.61–1.09]; P =0.167), but visual inspection of pooled Kaplan–Meier curves suggested a divergence favoring S‐ICD. Secondary outcomes did not differ significantly between both modalities. Conclusions S‐ICD is clinically superior to TV‐ICD in terms of lead‐related complications while demonstrating comparable efficacy and safety. For device‐related complications, S‐ICD may be beneficial over TV‐ICD in the long term. These indicate that S‐ICD is likely a suitable substitute for TV‐ICD in patients requiring implantable cardioverter‐defibrillator implantation without a pacing indication.

Clinical outcomes of subcutaneous vs. transvenous implantable defibrillator therapy in a polymorbid patient cohort

“…We did not observe technical or mechanical problems with S-ICDs leads, while one lead infection occurred in a S-ICD patient. This is in line with the results from Fong's meta-analysis observing significantly lower lead-related complications in S-ICD patients (RR = 0.14; 95% CI 0.07–0.29; p < 0.0001) ( 36 ) as well as according to data from the PRAETORIAN trail and Brouwers dual-center propensity score-matched cohort ( 32 ). Fong observed no significant difference in device-related complications (RR = 0.59; 95 % CI 0.33–1.04; p = 0.07) ( 36 ).…”

“…Several clinical trials used propensity-score matching as primary statistical method to pseudo-randomize TV-ICD and S-ICD therapy in a real-life cohort ( 32 – 35 ). Their results, as well as the results from the PRAETORIAN trial, were incorporated in a recently published meta-analysis by Fong and colleagues revealing no significant difference in mortality between the two ICD types ( 36 ). Interestingly, the authors provided a pooled Kaplan-Meier analysis to investigate the survival probability.…”

“…Interestingly, the authors provided a pooled Kaplan-Meier analysis to investigate the survival probability. Visual inspection indicates divergence of the two curves after a 4-year follow-up favoring a better survival in patients with S-ICD, although differences were not statistically significant ( 36 ). The EFFORTLESS S-ICD registry was designed to obtain clinical outcome data in S-ICD patients implanted with early generation devices ( 10 ).…”

The subcutaneous implantable cardioverter-defibrillator should be considered for all patients with an implantable cardioverter-defibrillator indication

“…Last, but not least, a recent systematic review and meta-analysis, which was a pooled analysis of 5 high-quality studies (1195 patients received S-ICD; 1192 patients received TV-ICD), reported that patients implanted with the S-ICD had a lower risk of lead-related complications (risk ratio [RR] 0.14; P <.0001) at 30 to 60 months of follow-up. 54 Both the S-ICD and TV-ICD seemed to have similar rates of device-related complications (RR 0.59; P = .07), similar rates of infection (RR 0.94; P = .897), similar rates of appropriate shock therapy (RR 0.87; P = .732), and no significant differences in IAS therapy (RR 1.06; P = .695) and all-cause mortality (RR 1.02; P = .943). 54 …”

“… 54 Both the S-ICD and TV-ICD seemed to have similar rates of device-related complications (RR 0.59; P = .07), similar rates of infection (RR 0.94; P = .897), similar rates of appropriate shock therapy (RR 0.87; P = .732), and no significant differences in IAS therapy (RR 1.06; P = .695) and all-cause mortality (RR 1.02; P = .943). 54 …”