Early complications and long-term outcome of patients treated with a Subcutaneous Cardioverter-Defibrillator: temporal trends and clinical implications of the anesthetic strategies adopted at implant

BACKGROUND AND AIMS: Subcutaneous implantable cardioverter defibrillator (S-ICD) therapy is well-established therapy for the prevention of sudden cardiac death. Although general anesthesia (GA) was initially advocated for implantation, non-GA has emerged as a feasible alternative in clinical practice. This study evaluated the early and long-term outcomes associated with anesthetic modality during S-ICD implantation procedures. METHODS: The HONEST study nationwide, single-arm, observational cohort included all patients implanted with an S-ICD (EMBLEM™, Boston Scientific) in France between 2012 and 2019. GA was characterized by controlled unconsciousness with airway management, while non-GA included all alternative techniques. RESULTS: Among 4,924 patients, 1,041 (21.1%) underwent non-GA. The proportion of non-GA use increased from 2.5% to 26.9% between 2012 and 2019 (p<0.001). Patients implanted with non-GA modality tended to be older (51 ± 14 vs. 50 ± 15 years), had lower left ventricular ejection fraction (41±16 vs. 43±17%), and fewer secondary prevention indications (33 vs. 38%) (all p<0.01). Thirty-day complication rate was 3.4% in the non-GA group (vs 3.7% in the GA group; p=0.85). At follow-up, the incidence of overall complications (4.29 events per 100 person-years for non-GA versus 4.73 for GA; p=0.937), reintervention (1.21 versus 1.62; p=0.963), inappropriate shocks (2.88 versus 2.78; p=0.782), and all-death (2.93 versus 2.56; p=0.938) were similar between groups. Multivariate analysis confirmed that there were no differences across outcomes (all p values>0.1). CONCLUSION: Anesthesia strategy used for S-ICD implantation was not associated with poorer short- or long-term clinical outcomes, supporting non-general anesthesia as a feasible alternative in appropriately selected patients.