Subcutaneous implantable cardioverter-defibrillator Post-Approval Study: Clinical characteristics and perioperative results

Background The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to reduce short- and long-term complications associated with transvenous ICD leads. Early multicenter studies included younger patients with less left ventricular systolic dysfunction and fewer comorbidities than cohorts with traditional ICD. Objective The purpose of this study was to characterize patient selection and the acute performance of the S-ICD in a contemporary real-world setting. Methods The S-ICD Post-Approval Study is a prospective registry involving 86 US centers. Patients were enrolled if they met criteria for S-ICD implantation, passed an electrocardiogram screening test, and had a life expectancy of >1 year. Analyses of descriptive statistics, Kaplan-Meier time to event, and multivariate logistic regression were performed. Results The study includes 1637 patients who underwent S-ICD implantation. The cohort included 68.6% (1123/1637) male patients, and 13.4% (220/1636) were receiving dialysis for end-stage renal disease. The mean age was 52 ± 15 years, with a mean left ventricular ejection fraction of 32.0% ± 14.6%. Electrocardiogram screening was successful for at least 1, 2, or 3 vectors in 100%, 93.8%, and 51.4% of patients, respectively. Medical imaging (65.1%, 1065/1636) and general anesthesia (64.1%, 1048/16) were used in a majority of patients, and 52.2% (855/1637) were implanted with the 2-incision technique. Induced ventricular tachycardia/ventricular tachycardia was successfully converted in 98.7% (1394/1412) of patients. The 30-day complication-free rate was 96.2%. Predictors of complications included diabetes, younger age, and higher body mass index. Conclusion Contemporary US patients with S-ICD have more comorbidities than do previous cohorts with S-ICD, but they are younger with more end-stage renal disease than do patients with transvenous ICD. Implantation success is high, and short-term complication rates are acceptable.