Subcutaneous implantable cardioverter‐defibrillator in primary and secondary prevention of sudden cardiac death: A meta‐analysis

BACKGROUND: Subcutaneous implantable cardioverter-defibrillator (S-ICD) is gaining in popularity for primary and secondary prevention of sudden cardiac death. The objective was to evaluate the safety and clinical effectiveness of the S-ICD for prevention of sudden cardiac death compared to transvenous cardioverter-defibrillator (TV-ICD). METHODS: A systematic review with meta-analyses was performed. The electronic databases MEDLINE, EMBASE, SCI, and Cochrane Central Register of Controlled Trials were consulted in March 2018 with no restrictions on publication date. Predefined criteria were used to determine inclusion of studies and to assess their methodologic quality. RESULTS: Ten longitudinal-observational studies with comparison group presenting moderate methodologic flaws were included (N = 7820). The combination of results indicates that health-related quality of life is not significantly different between S-ICD and TV-ICD groups (Physical health: MD = 2.90; 95% CI = -3.88, 9.68/Mental health: MD = 0.13; 95% CI = -2.11, 2.37). Mortality occurred in 4.4% of S-ICD patients and 5.9% of TV-ICD patients died (OR = 0.79; 95% CI = 0.50, 1.24). The incidence of infections (OR = 1.79; 95% CI = 0.93, 3.43) and inappropriate shocks (OR = 1.28, 95% CI = 0.91, 1.78) is not significantly different between both groups. The S-ICD reduces complications related to electrodes/leads (OR = 0.13, 95% CI = 0.05, 0.29) and has lower electrodes/leads movement compared with TV-ICD (OR = 0.26; 95% CI 0.10, 0.67). In contrast, pneumothorax is more likely in TV-ICD than S-ICD (OR = 0.17; 95% CI = 0.03, 0.97). CONCLUSIONS: S-ICD reduces electrodes/leads movement, electrodes/leads related complications, and pneumothorax. Our study did not demonstrate a statistically significant difference in mortality, health-related quality of life, and infection rate between S-ICD and TV-ICD.