No abstract

Background: Sodium, apart from volume, may have an independent effect on blood pressure (BP) regulation. Methods: Sixteen hypertensive hemodialysis patients were enrolled, who have achieved their dry weight assessed by bioimpedance methods, with pre-dialysis plasma sodium levels slightly higher than the facility dialysate sodium concentration 138 mmol/l. After a 1-month period of dialysis with standard dialysate sodium concentration of 138 mmol/l, the patients were followed up for a 4-month period with dialysate sodium set at 136 mmol/l. Results: Along with lowering dialysate sodium, there were significant decreases (-10 mm Hg and -6 mm Hg) in 44-hour ambulatory systolic and diastolic BP at 4 months. Interdialytic weight gain adjusted to the estimated dry weight mildly but significantly decreased (4.81 ± 1.51 vs. 4.36 ± 1.37%, p = 0.047). The post-dialysis volume parameters remained constant throughout the study period. Conclusion: In selected hypertensive hemodialysis patients with optimal dry weight, increasing diffusive sodium removal resulted in significant BP decrease. It was probably due to a volume-independent effect.

Background: Chronic fluid overload due to overestimation of dry weight (DW) is the major factor in the development of hypertension in hemodialysis (HD) patients. The present study was undertaken to investigate whether bioimpedance ratio in the calf (Calf-BR = impedance at 200 kHz/impedance at 5 kHz) could be a useful hydration marker for estimation of DW and facilitate better control of blood pressure (BP) in HD patients. Methods: Target range of Calf-BR was derived from 157 healthy Chinese subjects. Post-dialysis Calf-BR was measured in 117 stable, non-edematous HD patients. Those with Calf-BR(s) above target level had their DW(s) gradually reduced under the guidance of Calf-BR. Results: The Calf-BR was normally distributed and increased with age, but was independent of BMI and gender in both healthy subjects and dialysis patients. HD patients with Calf-BR above age-stratified target range had significantly higher home BP, in spite of more antihypertensive treatments (p = 0.058). The patients who reached the target range of Calf-BR by decreasing DW, had their home BP significantly decreased, along with reduction in antihypertensive medications (p = 0.012). Conclusion: Recognition and correction of chronic fluid overload based on age-stratified Calf-BR is helpful in hypertension control in Chinese HD patients.