Residual Kidney Function and Response of Left Ventricular Mass to Intensive Hemodialysis

Key Points Residual kidney function does not modify the response of left ventricular mass (LVM) to frequent hemodialysis in patients with ESKD. Both anuric and nonanuric patients showed similar improvements in LVM with intensive hemodialysis. Changes in residual kidney function were not associated with response of LVM to frequent hemodialysis. Background Frequent (6 times/wk) hemodialysis has been shown to reduce left ventricular mass (LVM) more than conventional (3 times/wk) hemodialysis in patients with ESKD. Previous work suggested that the LVM benefits of frequent hemodialysis might be attenuated in the presence of residual kidney function (RKF). We hypothesized that patients without RKF would have greater LVM reduction with frequent hemodialysis compared with patients with RKF. Methods We analyzed data from the Frequent Hemodialysis Network (FHN) Daily (in-center) and Nocturnal (home-based) trials, which randomized patients with ESKD to either frequent or conventional hemodialysis over 12 months. RKF was evaluated through timed 24-hour urine collections, with anuria defined as urine output <100 ml/day. LVM was assessed through magnetic resonance imaging at baseline and 12 months. Combined trial data were analyzed using log-transformed LVM to evaluate the effect of RKF on LVM change. Results Among 332 patients from both FHN trials (170 frequent, 162 conventional hemodialysis), 189 (57%) were anuric at baseline. Baseline LVM did not differ between anuric and nonanuric patients (log LVM: 4.90±0.32 versus 4.85±0.40; P = 0.18). At 12 months, both anuric and nonanuric patients experienced similar LVM reductions with frequent hemodialysis (mean change in log LVM: −0.11±0.23 versus −0.08±0.23; P = 0.44). No association was found between baseline urine volume and LVM response (rho=−0.002, P = 0.98 for frequent; rho=0.003, P = 0.97 for conventional hemodialysis). Changes in urine volume over 12 months did not correlate with LVM changes. In an exploratory analysis, LVM reduction correlated with urine volume decline in men (rho=0.23; P < 0.01) but not in women (rho= −0.19; P = 0.10; P interaction = 0.003). Conclusions Both anuric and nonanuric patients experienced similar LVM reductions with frequent hemodialysis, and no association between urine output and LVM response was observed in the FHN trials. These data suggest that the response of LVM to frequent hemodialysis is independent of baseline RKF.