Feasibility, efficacy and safety of subcutaneous implantable cardioverter defibrillator in patients with a previous median sternotomy

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Subcutaneous implantable cardioverter defibrillator (S-ICD) has been shown to be an effective therapy for prevention of sudden cardiac death (SCD) with improved outcomes and fewer lead-related complications compared to transvenous cardioverter defibrillator (TV-ICD). Patients who previously underwent cardiac surgery with median sternotomy (MS) may be at risk of SCD and require ICD implantation. However, there are no data on the performance of the S-ICD in this patient cohort. Purpose To assess feasibility, periprocedural and long-term complications associated with implantation of S-ICD in patients with a previous MS. Methods All 128 patients who received a S-ICD at our Centre were enrolled in the study. Baseline and procedural characteristics and complications were collected and retrospectively analyzed. Long-term outcomes were considered as appropriate and inappropriate shocks (IAS), and complications during follow-up. To estimate arrhythmia-free survival, Kaplan–Meier curves were constructed. Cox regression was performed to analyze multivariate predictors of recurrences. Results Among 128 patients (79.7% male sex; mean age 50±15 years), 18 of them had a previous MS. Coronary artery disease was present in 26.6% of the total population, while not ischemic aetiology was present in the 75.4% of them; among this cohort, the most prevalent pathology was hypertrophic cardiomyopathy (21.9%). Primary prevention cohort was the 61.1% in the MS group and the 77.3% in the no MS group. S-ICD implant was successful in 100% of cases. No periprocedural complications were registered. After a median follow up of 3.9 years, no one of the 101 patients had sternal complications. There were no differences in delivery of appropriate shocks (12.5% in MS group vs 7.69% in no MS group, p=0.583) neither in delivery of IAS (6.25% in MS group vs 9.89% in no MS group, p=0.594). At the univariate analysis on IAS there were no differences between the group with or without MS (10% vs 16.38%, p=0.594), but there were significative differences between patients with or without arrhythmogenic right ventricular dysplasia (ARVC; 20% vs 2%, p=0.006), between patients with or without diabetes (30% vs 9.89%, p=0.03), between patients with or without chronic obstructive pulmonary disease (30% vs 4.39%, p=0.002) and between patients who used to smoke and patient who did not (40% vs 16.48%, p=0.03). At multivariate analysis, advanced age (hazard ratio 1.033; 95% CI, 1.014 to 1.053; p=0.001) and ARVC (hazard ratio 5.133; 95% CI, 1.515 to 17.399; p=0.009) were significantly associated with delivery of IAS. Conclusion Implanting a S-ICD is feasible, safe and effective as in patients without a previous MS; in patients who underwent a S-ICD, a previous MS is not associated with a major risk of sternal complications or delivery of IAS; advanced age and ARVC are independently associated with a major risk of delivery of IAS.