Impact of Renal Function on Survival After Cardiac Resynchronization Therapy

Chronic kidney disease (CKD) is associated with worse survival in patients with heart disease including those with implantable devices. Cardiac resynchronization therapy (CRT) can potentially improve renal function. To assess the relation between the change in renal function and survival with CRT, 238 patients undergoing initial CRT with defibrillator implantation between 2002 and 2011 were followed. The primary end point was all-cause mortality. The estimated glomerular filtration rate (eGFR), before implantation and 6 ± 3 months after CRT was calculated. Patients were grouped at baseline into mild (stage I/II) or advanced (stage III/IV) CKD. Patients with end-stage renal disease were excluded. The mean follow-up time was 4.3 years. Multivariate analysis of baseline clinical characteristics showed that only renal function predicted the change in eGFR over the first 6 months of CRT. In the subgroup with mild CKD, eGFR decreased (78.5 ± 17.3 to 67.8 ± 26.8 p <0.001), whereas eGFR did not change in the subgroup with advanced CKD (45.6 ± 11.1 to 46.8 ± 17.0, p = 0.46). Patients with advanced CKD had higher mortality than those with mild CKD (p <0.002). In both subgroups, an increase in eGFR was associated with improved survival (hazard ratio = 0.79, p <0.001). In conclusion, baseline renal function and the subsequent change in eGFR are associated with long-term survival with CRT.