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Am J Kidney Dis. 2015 Mar;65(3):464-73. doi: 10.1053/j.ajkd.2014.10.021. Epub 2014 Dec 17.

Effect of low versus high dialysate sodium concentration on blood pressure and endothelial-derived vasoregulators during hemodialysis: a randomized crossover study.

Author information

1
Division of Nephrology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX; Department of Internal Medicine, Duke University, Durham, NC; Department of Medicine, Quintiles Global Clinical Research Organization, Morrisville, NC. Electronic address: jula.inrig@duke.edu.
2
School of Medicine, University of Texas Southwestern Medical Center, Dallas, TX.
3
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX.
4
Division of Nephrology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX.
5
Department of Internal Medicine, Duke University, Durham, NC.

Abstract

BACKGROUND:

Intradialytic hypertension affects ∼15% of hemodialysis patients and is associated with increased morbidity and mortality. While intradialytic hypertension is associated with increases in endothelin 1 relative to nitric oxide (NO), the cause of these imbalances is unknown. In vitro evidence suggests that altering plasma sodium levels could affect endothelial-derived vasoregulators and blood pressure (BP). Thus, we hypothesized that compared to high dialysate sodium, low dialysate sodium concentration would lower endothelin 1 levels, increase NO release, and reduce BP.

STUDY DESIGN:

3-week, 2-arm, randomized, crossover study.

SETTING & PARTICIPANTS:

16 patients with intradialytic hypertension.

INTERVENTION:

Low (5 mEq/L below serum sodium) versus high (5 mEq/L above serum sodium) dialysate sodium concentration.

OUTCOMES:

Endothelin 1, nitrite (NO2(-)), and BP.

MEASUREMENTS:

Mixed linear regression was used to compare the effect of dialysate sodium (low vs high) and randomization arm (low-then-high vs high-then-low) on intradialytic changes in endothelin 1, NO2(-), and BP values.

RESULTS:

The average systolic BP throughout all hemodialysis treatments in a given week was lower with low dialysate sodium concentrations compared with treatments with high dialysate sodium concentrations (parameter estimate, -9.9 [95% CI, -13.3 to -6.4] mm Hg; P < 0.001). The average change in systolic BP during hemodialysis also was significantly lower with low vs high dialysate sodium concentrations (parameter estimate, -6.1 [95% CI, -9.0 to -3.2] mm Hg; P < 0.001). There were no significant differences in intradialytic levels of endothelin 1 or NO2(-) with low vs high dialysate sodium concentrations.

LIMITATIONS:

Carryover effects limited the power to detect significant changes in endothelial-derived vasoregulators, and future studies will require parallel trial designs.

CONCLUSIONS:

Low dialysate sodium concentrations significantly decreased systolic BP and ameliorated intradialytic hypertension. Longer studies are needed to determine the long-term effects of low dialysate sodium concentrations on BP and clinical outcomes.

KEYWORDS:

Intradialytic hypertension; Mechanisms and Treatment of Intradialytic Hypertension–Sodium (MATCH-NA) Study; blood pressure (BP); dialysate sodium concentration; end-stage renal disease (ESRD); endothelin 1; endothelium; hemodialysis; nitric oxide; nitrite; serum sodium concentration; sodium gradient; vasoregulation

PMID:
25530107
DOI:
10.1053/j.ajkd.2014.10.021
[Indexed for MEDLINE]

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