Device-related infection in de novo transvenous implantable cardioverter-defibrillator Medicare patients.

BACKGROUND: Cardiac device infection is a serious complication of implantable cardioverter-defibrillator (ICD) placement and requires complete device removal with accompanying antimicrobial therapy for durable cure. Recent guidelines have highlighted the need to better identify patients at high risk of infection to assist in device selection. OBJECTIVE: To estimate the prevalence of infection in de novo transvenous (TV) ICD implants and assess factors associated with infection risk in a Medicare population. METHODS: A retrospective cohort study was conducted using 100% Medicare administrative and claims data to identify patients who underwent de novo TV-ICD implantation (July 2016-December 2017). Infection within 720 days of implantation was identified using ICD-10 codes. Baseline factors associated with infection were identified by univariable logistic regression analysis of all variables of interest, including conditions in Charlson and Elixhauser comorbidity indices, followed by stepwise selection criteria with a P ≤ .25 for inclusion in a multivariable model and a backwards, stepwise elimination process with P ≤ .1 to remain in the model. A time-to-event analysis was also conducted. RESULTS: Among 26,742 patients with de novo TV-ICD, 519 (1.9%) developed an infection within 720 days post implant. While more than half (54%) of infections occurred during the first 90 days, 16% of infections occurred after 365 days. Multivariable analysis revealed several significant predictors of infection: age <70 years, renal disease with dialysis, and complicated diabetes mellitus. CONCLUSION: The rate of de novo TV-ICD infection was 1.9%, and identified risk factors associated with infection may be useful in device selection.

Heart rate score predicts mortality independent of shocks in ICD and CRT-D patients.

BACKGROUND: Heart Rate Score (HrSc), a novel index found to predict mortality in patients with implantable defibrillator (ICD) and cardiac resynchronization defibrillator (CRT-D) devices, is associated with mortality in ICD and CRT-D recipients when HrSc is ≥ 70%. Implantable defibrillator shocks have also been associated with increased mortality in ICD and CRT-D recipients. The objective of this study was to evaluate the relationships between HrSc, shocks, and mortality in ICD and CRT-D patients. METHODS: HrSc was calculated from atrial sensed and paced rate histograms collected from the 2006-2011 ALTITUDE remote interrogation database. Shocks were determined in the first year of follow-up. Mortality was assessed over the next 4 years by the Social Security Death Index. Four multivariable models were run: ICD and CRT-D, shock and no shock, with mortality as the outcome and HrS as predictor. RESULTS: Data from 49,358 ICD and 55,953 CRT-D patients were divided into HrSc: ≥ 70%, 30-69%, and < 30%. Shock rates differed between HrSc groups (p < 0.001) for ICD and CRT-D patients. However, the lowest mortality risk HrSc (< 30%) had the highest shock rate. Both highest HrSc (> 70%; p < 0.001) and shocks (p < 0.001) predicted mortality during follow-up. Mortality was unrelated to interactions between HrSc and shocks in ICD patients (p = 0.275) or CRT-D patients (p < 0.079). Comparing HrSc ≥ 70% to HrSc < 30%, HrSc ≥ 70% predicted mortality in CRT-D (HR 1.40; 95% CI 1.29-1.52) and ICD (HR 1.23; 95% CI 1.11-1.36) patients regardless of shocks (P < 0.001 for both). CONCLUSIONS: Patients with ICDs or CRT-Ds having the lowest mortality risk HrSc had the highest shock rate. Shocks and HrSc appear to complement each other as predictors of mortality.