Effect of Dietary Sodium Intake on Vascular Endothelium

This study is currently recruiting participants.
Verified January 2013 by Vanderbilt University
Sponsor:
Information provided by (Responsible Party):
Satish R. Raj, Vanderbilt University
ClinicalTrials.gov Identifier:
NCT01550315
First received: March 2, 2012
Last updated: January 7, 2013
Last verified: January 2013

March 2, 2012
January 7, 2013
April 2012
March 2017   (final data collection date for primary outcome measure)
RH-PAT Index [ Time Frame: On steady state (after 5 days) low and high sodium diets ] [ Designated as safety issue: No ]
The primary analysis will involve a non-parametric, paired, Signed Rank test of RH-PAT between all subjects (POTS & control subjects) on the high sodium diet vs low sodium diet
Same as current
Complete list of historical versions of study NCT01550315 on ClinicalTrials.gov Archive Site
fasting glucose and insulin levels [ Time Frame: after steady state has been reached (>5 days) on low and high sodium diets ] [ Designated as safety issue: No ]
Secondary analyses will include non-parametric paired comparisons between low sodium and high sodium diets of continuous outcome measures (outlined in section 7.3). Secondary comparisons might also assess differences in the dietary sodium induced changes between POTS patients and control subjects.
Same as current
Not Provided
Not Provided
 
Effect of Dietary Sodium Intake on Vascular Endothelium
A Pilot Study of the Effect of Dietary Sodium Intake on Assessments of Vascular Endothelium

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.

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

Interventional
Not Provided
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Basic Science
Postural Tachycardia Syndrome (POTS)
  • 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.
    Other Name: EndoPat
  • 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
    Other Name: Hokansan strain guage venous plethysmography
  • 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.
    Other Name: Ultrasound
  • Active Comparator: High Sodium - POTS & Controls
    Subjects will receive a high sodium diet for 4-5 days prior to study day. Procedures include: blood work, urine collection, Pulsitile Arterial Tonometry (PAT), PAT analysis, Calf Blood Flow in Reactive Hyperemia (CBF-RH), & evaluation of forearm-mediated dilation.
    Interventions:
    • Procedure: Pulsitile Arterial Tonometry (PAT) Protocol
    • Device: Calf Blood Flow in Reactive Hyperemia (CBF-RH)
    • Device: Evaluation of Forearm-Mediated Dilation
  • Low Sodium Diet (POTS & Controls)

    Participants will consume a very low sodium diet (10 mEq/day) for 4-5 days prior to study day.

    Procedures include: blood work, urine collection, Pulsitile Arterial Tonometry (PAT), PAT analysis, Calf Blood Flow in Reactive Hyperemia (CBF-RH), & evaluation of forearm-mediated dilation.

    Interventions:
    • Procedure: Pulsitile Arterial Tonometry (PAT) Protocol
    • Device: Calf Blood Flow in Reactive Hyperemia (CBF-RH)
    • Device: Evaluation of Forearm-Mediated Dilation

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
50
March 2017
March 2017   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Subjects will be enrolled in the parent study "Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387 Postural Tachycardia Syndrome
  • Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic Dysfunction Center
  • Subjects will be enrolled in the parent study "Dietary Salt in Postural Tachcyardia Syndrome" funded by R01 HL102387
  • Postural Tachycardia Syndrome
  • Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic Dysfunction Center
  • Increase in heart rate ≥30 beats/min with position change from supine to standing (10 minutes)
  • Chronic symptoms consistent with POTS that are worse when upright and get better with recumbence Control Subjects
  • Healthy, non-obese, non-smokers without orthostatic tachycardia
  • Selected to match profiles of POTS patients (gender, age)
  • Not using vasoactive medication
  • Age between 18-60 years
  • Male and female subjects are eligible.
  • Able and willing to provide informed consent

Exclusion Criteria:

  • Overt cause for postural tachycardia (such as acute dehydration)
  • Inability to give, or withdrawal of, informed consent
  • Pregnant
  • Other factors which in the investigator's opinion would prevent the subject from completing the protocol.
Both
18 Years to 60 Years
Yes
Contact: Satish R Raj, MD, MSCI 615-322-2931 adcresearch@vanderbilt.edu
Contact: Victor Nwazue, MD, ChB 615-322-3304 adcresearch@vanderbilt.edu
United States
 
NCT01550315
111577
No
Satish R. Raj, Vanderbilt University
Vanderbilt University
Not Provided
Principal Investigator: Satish R Raj, MD MSCI Vanderbilt University
Vanderbilt University
January 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP