Abstract 14884: Patients with Renal Impairment Derive Long-Term Benefit from Cardiac Resynchronization Therapy: Results from the MADIT-CRT Long-Term Follow-Up

Abstract

Background: Whether patients with renal impairment experience benefit from cardiac resynchronization therapy plus an implantable cardioverter-defibrillator (CRT-ICD) during long-term follow-up is unknown. Hypothesis: We assessed the hypothesis that baseline renal function affects long-term risk of all-cause mortality and heart-failure events (HFEs) as well as benefit derived from CRT-ICD. Methods: We evaluated the impact of renal function in 1274 patients with mild heart failure and left-bundle branch block enrolled in MADIT-CRT. Patients with BUN>70 mg/dl or creatinine>3.0 mg/dl were excluded from the trial. Two subgroups were created based on the estimated glomerular filtration rate (GFR): GFR<60 and GFR≥60 ml/min/1.73 m2. Patients were studied over a follow-up period of 7 years for the end points of all-cause mortality and HFEs. Results: There were 413 patients with baseline GFR<60 ml/min/1.73 m2 (mean 48.1±8.3). Relative to those with GFR≥60 ml/min/1.73 m2 (mean 79.6±16.0), the low-GFR patients experienced greater risk of death (HR=2.14, 95% CI: 1.57-2.91, p<0.0001) and HFEs (HR= 1.31, 95% CI: 1.02-1.69, p=0.03). In both GFR groups, CRT-ICD relative to ICD alone was associated with significantly lower risk of death (GFR<60: HR=0.63, 95% CI: 0.42-0.94, p=0.024, absolute risk reduction [ARR]=12%; GFR≥60: HR=0.65, 95% CI: 0.42-0.99, p=0.049, ARR=8%) [Figure]. Similarly, there was significant reduction in the risk of HFEs (GFR<60: HR=0.36, 95% CI: 0.25-0.53, p<0.0001, ARR=27%; GFR≥60: HR= 0.42, 95% CI: 0.31-0.57, p<0.0001, ARR=17%). Conclusion: In conclusion, in mild heart failure patients, moderate renal dysfunction is associated with higher risk of all-cause mortality and HFEs relative to mildly impaired-to-normal renal function. While patients in both groups derive long-term benefit from CRT-ICD with similar relative reductions in all-cause mortality and HFEs, the greater absolute benefit occurs in patients with moderate renal disease.