Abstract
BACKGROUND: Implantable cardioverter-defibrillator (ICD) generator replacement at the end of expected battery life accounts for a substantial proportion of all ICD implant procedures. However, little is known about the predictors of mortality following ICD generator replacement. OBJECTIVE: The purpose of this study was to identify clinical and procedural factors associated with death following ICD generator replacement. METHODS: Patients from the National Cardiovascular Data Registry (NCDR) ICD Registry receiving ICD generator replacements at the end of device battery life between January 1, 2005, and March 30, 2010, were eligible. Predictors of mortality were determined using multivariable Cox regression. RESULTS: Analysis of 111,826 patients (mean age 70.7 ± 12.4, 75.5% male) revealed 1-, 3-, and 5-year mortality of 9.8%, 27.0%, and 41.2%, respectively. After adjustment, atrial fibrillation (hazard ratio [HR] 1.23, 95% confidence interval [CI] 1.20-1.27) and congestive heart failure (HR 1.21, 95% CI 1.16-1.27) predicted worse survival. In addition to older age (HR 1.43, 95% CI 1.41-1.45), several noncardiac conditions were also associated with poorer survival, including chronic lung disease (HR 1.53, 95% CI 1.49-1.57), cerebrovascular disease (HR 1.28, 95% CI 1.24-1.32), diabetes (HR 1.27, 95% CI 1.23-1.30), and lower glomerular filtration rate (HR 1.15 for each 10-unit increment decline, 95% CI 1.14-1.16). In the absence of a non-ICD control group, risk reduction provided by ICD therapy in this cohort is not known. CONCLUSION: In addition to age, atrial fibrillation, and congestive heart failure, noncardiac comorbidities are associated with higher mortality following ICD replacement, which should be considered in the decision to undergo this procedure.