Comparing the safety of subcutaneous versus transvenous ICDs: a meta-analysis

The use of transvenous implantable cardioverter defibrillators (TV-ICDs) is associated with multiple risks related to the presence of the defibrillator leads within the venous system and right side of the heart, including endocarditis, venous occlusion, tricuspid regurgitation, and potential lead failure. The emergence of subcutaneous ICDs (S-ICDs) may potentially overcome the aforementioned disadvantages. However, evidence validating the safety of S-ICDs relative to TV-ICDs is limited. The present study aimed to synthesize and analyze available data from published studies to comprehensively compare transvenous and subcutaneous ICDs.

Different databases were searched for full-text publications with a direct comparison of TV- and S-ICDs. Fixed effect models were applied to pooled data, and no study-to-study heterogeneity was detected.

Data from 7 studies totaling 1666 patients were pooled together. Compared to S-ICDs, the risk of suffering device-related complications was higher in patients with TV-ICDs (OR = 1.71; 95% CI: 1.23-2.38). The number of patients with an S-ICD who suffered inappropriate shocks (IS) was not significantly different than patients with a TV-ICD (OR = 0.92; 95% CI: 0.65-1.30). Subgroup analysis indicated that the TV-ICD group had a higher risk of IS due to supraventricular oversensing (OR = 3.29; 95% CI: 1.92-5.63) while T-wave oversensing tending to cause IS in the S-ICD group (OR = 0.09; 95% CI: 0.03-0.23). The risk of device-related infection in the S-ICD group was not any lower than that in the TV-ICD group (OR = 1.57; 95% CI: 0.67-3.68). The survival rate without any complications during a 1-year follow-up period was similar between the 2 groups (HR = 1.23; 95% CI: 0.81-1.86), although it was assumed that the trend leaned toward more complications in patients with a TV-ICD.

The present study verified the safety of S-ICDs based on pooled data. Although there were no differences between TV- and S-ICDs in the short term, fewer adverse events were found in patients with S-ICDs during long-term follow-up.