Implantable cardioverter defibrillators confer survival benefit in patients with renal insufficiency but not in dialysis-dependent patients

Abstract

Randomized clinical trials have demonstrated that the implantable cardioverter defibrillator (ICD) reduces mortality in heart failure patients with reduced systolic function but have excluded patients with advanced chronic kidney disease (CKD). We investigated the impact of ICDs on survival in patients with moderate-to-severe CKD, including those requiring dialysis therapy (DT). Patients followed at our institution between 1998 and 2008 with left ventricular ejection fraction (LVEF) ≤35% and CKD, defined as glomerular filtration rate (GFR) <60 mL/min, or who were on DT were identified from the medical record. The primary endpoint of all-cause death was analyzed by ICD status. A total of 78 patients (${\hbox{age}} = 66\pm 12\;{\hbox{years}}$, 73% men, ${\hbox{EF}} = 0.24\pm 0.07$, GFR 39 ± 12 mL/min in those not on DT) of whom 32 had an ICD were followed for 2.7 ± 2.3 years. In the DT (n = 45) cohort, the presence of an ICD did not impact survival. In the CKD with no DT cohort (n = 33), survival was significantly better in patients with an ICD (2-year survival 80% vs. 54%, p = 0.027), and this benefit persisted after adjusting for gender, race, GFR, digoxin use, and presence of coronary disease, heart failure, or hypertension in a multivariate Cox regression model (odd ratio = 0.23, adjusted p = 0.028). Defibrillators improve survival in CKD patients with LVEF ≤ 35%, whereas patients requiring DT do not appear to extract such benefit. Further studies with larger number of patients are required to confirm these findings.