Effects of lowering dialysate sodium on flow-mediated dilatation in patients with chronic kidney disease.

Objective: This study examined the effects of low dialysate sodium on endothelial dysfunction (ED) as measured by flow-mediated dilatation (FMD) of brachial artery in haemodialysis (HD) patients.

Methods: Thirty HD patients (17 men; mean age: 48.4 ± 17.8 years) were studied. Subjects underwent two consecutive 6-week HD periods. Dialysate sodium was 143 mEq/L in the first period (standard Na HD) and 137 mEq/L in the second period (low Na HD). After each period, we performed FMD, echocardiographic evaluation and 24-h ambulatory blood pressure monitoring (ABPM). Interdialytic weight gain (IDWG), levels of pre- and post-dialysis blood pressure (BP), and dialysis-related symptoms were monitored during the study.

Results: Per cent FMD was significantly greater (P < 0.05) after low Na HD (9.3 ± 6.2) compared with standard Na HD (5.7 ± 6.2). IDWG was significantly lower during low Na HD (2.35 ± 0.86 kg versus 2.71 ± 0.89 kg; P < 0.001). BP control was improved during low Na HD, as assessed by ABPM (128.2/77.5 mmHg versus 132.4/80.8 mmHg). Dialysis-related symptoms were more frequent during low Na HD (P < 0.05). There was no change in left ventricular mass after reducing dialysate sodium.

Conclusions: Reducing dialysate sodium concentration reduced ED, and provided better control of IDWG and BP, but increased dialysis-related symptoms.