What is the long term incidence and the natural history of infection of subcutaneous implantable cardioverter-defibrillators? Results from a nationwide cohort

Abstract Background Subcutaneous implantable cardioverter-defibrillators (S-ICD) infections remain poorly studied. Objective The aim of this study to describe infections occurring in patients implanted with S-ICD (incidence, site, severity, bacteriological findings, risk factors, management and outcome) within the HONEST cohort. Methods We enrolled 4,924 patients (from 150 nationwide hospitals, 2012-2019) with ongoing follow-up. Infection cases were meticulously collected and adjudicated. Outcomes were classified using standardized criteria. Infection management included conservative treatment (antibiotics ± surgical revision) and device extraction. Results 113 patients (2.3%) experienced 116 infections through a mean follow-up of 4.2 ± 2.2 years. Infection incidence was 1.8% at 1 year, 2.4% at 5 years and 3.6% at 8 years). The majority of infections occurred within the first year (84%). Risk factors included female gender (HR 2.17), diabetes (HR 2.19), associated pacemaker (HR 3.55), three incisions (HR 1.55), and pocket hematoma (HR 7.52). We report the occurrence of recurrent infection (3 cases, 2.7%), systemic infections (8 cases ,6.9%), infective endocarditis (1 cases, 0.9%), septic shock (2 cases, 1.8%), and infection related mortality (2 cases, 1.8%). Staphylococcal infections were the most common. Conservative management was effective in 41.5% of cases. Device removal was necessary in 81.0% of cases, with 67.0% new ICD implantation. Patients who underwent S-ICD removal had a higher rate of sudden cardiac death than those with preserved ICDs (9.6% vs. 1.2%, p = 0.030). Conclusion S-ICD infections remain an early complication. Efforts should be made to reduce the incidence of pocket hematoma. Conservative management may be considered. S-ICD reimplantation should be considered when extraction is unavoidable.