Abstract
BACKGROUND AND OBJECTIVES: Cardiac resynchronization therapy (CRT) is a well established heart failure treatment that has shown to improve renal function. However, landmark CRT trials excluded patients with severe renal dysfunction. Therefore, this study evaluated the effect of CRT on renal function and long-term prognosis in patients with stage 4 CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study evaluated 73 consecutive CRT patients (71±10 years) with stage 4 CKD who underwent echocardiographic and renal function evaluation at baseline and 6-month follow-up between 2000 and 2012. As a control group, 18 patients with stage 4 CKD who received an implantable cardioverter defibrillator (ICD) were selected. CRT recipients with ≥15% reduction in left ventricular end-systolic volume at 6-month follow-up were classified as CRT responders. During long-term follow-up (median, 33 months), appropriate defibrillator therapy, heart failure hospitalizations, and all-cause mortality (combined end point) were recorded. RESULTS: At 6-month follow-up, a significant reduction in left ventricular end-systolic volume was observed in CRT patients compared with patients with ICD (from 159±78 to 145±78 ml in CRT patients and from 126±54 to 119±49 ml in ICD patients; P=0.05), and CRT response was observed in 22 patients (30%). Compared with ICD patients, eGFR improved among CRT patients (from 25±4 to 30±9 ml/min per 1.73 m(2); interaction time and group, P=0.04) and was more pronounced among CRT responders (25±3 to 34±9 ml/min per 1.73 m(2); P<0.001). The combined end point was observed in 17 ICD and 62 CRT patients. CRT patients showed superior survival compared with ICD patients (log-rank P=0.03). More importantly, CRT response was independently associated with improved survival free from the combined end point (hazard ratio, 0.51; 95% confidence interval, 0.27 to 0.98; P=0.04) after adjustment for clinical and echocardiographic parameters. CONCLUSIONS: Response to CRT occurs in approximately 30% of patients with stage 4 CKD, which is less than in the average CRT population. CRT was associated with better clinical outcome, and particularly, CRT response was associated with improvement in eGFR and better long-term prognosis.