NCT01550315

Effect of Dietary Sodium Intake on Vascular Endothelium

A Pilot Study of the Effect of Dietary Sodium Intake on Assessments of Vascular Endothelium

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 27 (actual)
• Sponsor: Vanderbilt University Medical Center · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

Summary

The investigators will test the hypothesis that markers of vascular endothelial dysfunction will be exaggerated acutely with an extreme high sodium diet compared to an extreme low-sodium diet. The investigators will compare patients with postural orthostatic tachycardia (POTS) to healthy control subjects.

Detailed description

The study will involve a crossover design in which each subject will be assessed (as below) while on a very low-sodium (10 mEq/day) diet compared with a very high-sodium diet. These acute dietary interventions will be part of the parent study ("Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387) for 4-5 days at the time of the study. Dietary success will be assessed using a 24h urine for sodium and creatinine as a part of the parent study. Blood will be drawn and collected in a fasting state for future assay and analysis of the following tests: * Glucose, Insulin (glucose impairment, insulin resistance) * Fasting lipid profile * C-Reactive Protein (hsCRP) (inflammatory state) * Inflammatory cytokines (inflammatory state) * aliquots (future analysis) Pulsitile Arterial Tonometry (PAT) Protocol Calf Blood Flow in Reactive Hyperemia (CBF-RH) - venous occlusion plethysmography Evaluation of Forearm-Mediated Dilation

Conditions

• Postural Tachycardia Syndrome (POTS)

Interventions

Type	Name	Description
PROCEDURE	Pulsitile Arterial Tonometry (PAT) Protocol	* A blood pressure cuff will be placed on one upper arm (study arm; non-dominant), while the contralateral arm will serve as a control (control arm). * RH-PAT probes will be placed on one finger (finger II, III, or IV) of each hand (same finger on both hands). The fingers on either side of the one with the probe will be separated using soft sponge rings. * Continuous recording of pulsatile blood volume responses from both hands will be initiated. * After a 10-min equilibration period, the blood pressure cuff on the study arm will be inflated to 60 mm Hg above systolic pressure for 5 min. The cuff will then be deflated to induce reactive hyperemia, PAT recording will be stopped.
DEVICE	Calf Blood Flow in Reactive Hyperemia (CBF-RH)	Calf blood flow (CBF) will be determined using venous occlusion plethysmography and calibrated mercury strain-gauges during reactive hyperemia after a 5 min of ischemia of the distal limb. Strain-gauges will be applied to the widest part of the non-dominant calf (\~10 cm below patella). Participants will remain quietly supine for 10 min with legs elevated on foam pads above the right atrium to achieve stable baseline measurements of CBF. The venous occlusion cuff is inflated for 4 seconds at 8 seconds intervals, while monitoring the change in resistance in the system, pressure inside the measuring cuff, and 5-10 determinations are performed
DEVICE	Evaluation of Forearm-Mediated Dilation	The arm will be kept extended and immobilized at heart level. Brachial artery diameter will be measured using a high resolution ultrasonography using a linear array probe with a 5 to 17 MHz frequency range. The brachial artery will be imaged in longitudinal sections, 5-10 cm proximal to placement of an occlusion cuff in the dominant forearm just below the antecubital fossa. The probe will be held with a stereotaxic holder with micrometer movement capabilities.

Timeline

• Start date: 2012-04-01
• Primary completion: 2020-12-01
• Completion: 2021-09-01
• First posted: 2012-03-09
• Last updated: 2022-01-05
• Results posted: 2022-01-05

Locations

1 site across 1 country: United States