DEVICES Renal Response in Patients with Chronic Kidney Disease Predicts Outcome Following Cardiac Resynchronization Therapy GAURAV SINGAL, M.D.,* GAURAV A. UPADHYAY, M.D.,†,‡ RASMUS BORGQUIST, M.D., PH.D.,†,§ DANIEL J. FRIEDMAN, M.D.,* NEAL A. CHATTERJEE, M.D.,* JAGDESH KANDALA, M.D.,†,‡ MI YOUNG PARK, M.D.,‡ MARY ORENCOLE, ANP-BC,†,‡ GEORGE W. DEC, M.D.,‡ MICHAEL H. PICARD, M.D.,‡ JAGMEET P. SINGH, M.D., D.PHIL., F.H.R.S.,†,‡ and THEOFANIE MELA, M.D.†,‡ From the *Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; †Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston, Massachusetts; ‡Division of Cardiology, Massachusetts General Hospital, Boston, Massachusetts; and §Lund University, Arrhythmia Clinic, Skane University Hospital, Lund, Sweden Background: Chronic kidney disease (CKD) severity is associated with increased morbidity and mortality in congestive heart failure. There is a paucity of data regarding renal improvement after cardiac resynchronization therapy (CRT) and its potential impact on clinical outcomes, especially in patients with severe CKD. Method: This was a retrospective analysis of a prospectively collected cohort of 260 patients with CKD undergoing CRT at a single center. Renal function was compared before and after CRT. The primary end point was a composite of death, heart transplant, and left ventricular assist device (LVAD), assessed at 5 years. Results: Patients with more severe CKD demonstrated increased risk of death, transplant, or LVAD following CRT (P = 0.015). Renal response (estimated glomerular filtration rate improvement 10 mL/min/1.73 m 2 ) was observed in 14% of all patients and 28% of patients with stage IV CKD. Independent predictors of renal response included left ventricular ejection fraction improvement (odds ratio [OR] 1.06, confidence interval [CI] 1.01–1.10), angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use (OR 4.31, CI 1.08–17.23), and advanced CKD stage (OR 2.19, CI 1.14–4.23). Renal response independently decreased hazard of the primary outcome (HR 0.24, CI 0.08–0.73, P = 0.01). Renal responders with stage IV CKD had 80% 5-year event-free survival, compared to 0% for nonrenal responders in stage IV (P = 0.03). Conclusion: Although severity of CKD is associated with poorer outcome after CRT, improvement in renal function can occur in patients across all CKD stages. Renal responders, including those with stage IV CKD, demonstrate favorable 5-year outcomes. Assessment of renal response may help better prognostic outcomes following CRT. (PACE 2015; 38:1192–1200) heart failure, cardiorenal syndrome, chronic kidney disease, cardiac resynchronization therapy, pacemakers Funding sources: Dr. Borgquist was supported by grants from the Swedish Heart and Lung Foundation and by governmental funding of clinical research within the Swedish National Health Service. Disclosures: Gaurav Singal, Rasmus Borgquist, Daniel J. Friedman, Neal A. Chatterjee, Jagdesh Kandala, Mi Young Park, Mary Orencole, G. William Dec, and Michael H. Picard: none. Gaurav A. Upadhyay: salary support from the Max Schaldach Fellowship of the Heart Rhythm Society. Jagmeet P. Singh: consulting and research grants from Biotronik, Boston Scientific, Medtronic, St. Jude Medical, and Sorin Group. Theofanie Mela: speaking honoraria from St. Jude, Medtronic, Biotronik, and Boston Scientific. Introduction Cardiac resynchronization therapy (CRT) has been shown to improve left ventricular (LV) ejec- tion fraction (EF), reduce heart failure hospitaliza- tions, and decrease all-cause mortality in patients with heart failure and electrical dyssynchrony. 1–4 Address for reprints: Theofanie Mela, M.D., Cardiac Arrhyth- mia Service, Gray 109, Massachusetts General Hospital, 75 Fruit Street, Boston, MA 02114. Fax: 617-726-3852; e-mail: tmela@partners.org Received March 1, 2015; revised May 17, 2015; accepted July 5, 2015. doi: 10.1111/pace.12685 © 2015 Wiley Periodicals, Inc. 1192 October 2015 PACE, Vol. 38