Objective: The aim of the present study was to examine the effects of a mild increase in dialysis sodium removal on cardiovascular system in hypertensive hemodialysis (HD) patients. Methods: Sixty four HD patients with pre-HD plasma sodium level higher than 138mmol/l, were randomly assigned into 2 groups. The dialysate sodium was reduced from 138mmol/l to 136mmol/l in the intervention group, while remained at 138mmol/l in the control group. During the study course, home systolic blood pressure (BP) target of 140mmHg was used in all patients, and bioimpedance measurements to guide ultrafiltration were performed monthly. 44-hour ambulatory BP, aortic pulse wave velocity (PWV), left ventricular mass index (LVMI), pre-HD plasma sodium concentration, interdialytic weight gain, and dietary sodium intake, were measured. Results: Better BP control was achieved by 2 groups, with no significant differences. However, less annual averages of antihypertensives were used in the intervention group. The PWV values significantly decreased from 11.8 +/- 2.4 to 10.9 +/- 2.6m/s in the intervention group (P<0.001), and from 11.6 +/- 2.5 to 11.1 +/- 2.2m/s in the control group (P=0.012). LVMI regressed from 151 +/- 19 to 139 +/- 16 g/m2 (P<0.001) in the intervention group only. In addition, values for interdialytic weight gain and pre-HD plasma sodium decreased in the intervention group only. There were no significant differences in annual averages of dietary sodium intake and the frequency of adverse events between the 2 groups. Conclusions: Increasing dialysis sodium removal was associated with improvements in arterial stiffness, left ventricular hypertrophy, and better BP control in hypertensive HD patients. (C) 2016 by the National Kidney Foundation, Inc. All rights reserved.