Dietary Salt in Postural Tachycardia Syndrome

NCT01547117 | Completed Results

• 2 other identifiers: 111261R01HL102387
• Study Type: interventional
• Target: 38
• Locations: 1 country
• Sites: 1

Brief Summary

Patients with POTS may not adequately expand their plasma volume in response to a high-sodium (Na+) diet. Mechanisms involved in the regulation of plasma volume, such as the renin-angiotensin-aldosterone system and renal dopamine, may be impaired in POTS and may respond inappropriately to changes in dietary sodium.The purpose of this study is to determine (1) whether a high dietary sodium level appropriately expands plasma volume in POTS; (2) whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in POTS; and (3) whether patients with POTS have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.

Conditions

Postural Orthostatic Tachycardia Syndrome

Keywords

POTS; Orthostatic Intolerance; Orthostatic Tachycardia

Outcome Measures

Primary Outcomes (1)

• Plasma Volume

  Plasma volume (PV) was determined by the indicator tracer-dilution technique, using the DAXOR Blood Volume Analyzer (BVA)-100 system (DAXOR Corporation), on Day 7 of the low sodium and high sodium dietary interventions. Outcome data are the absolute values for PV on Day 7 for each diet.

  after 7 days of each dietary sodium level

Secondary Outcomes (1)

• Magnitude of Suppression of Plasma Renin Activity (From Low Sodium to High Sodium Diets)

  Upright blood samples were collected after up to 30 minutes of standing on the 7th day of each dietary sodium intervention

Other Outcomes (3)

• Magnitude of Suppression of Serum Aldosterone (From Low Sodium to High Sodium Diets)

  Upright blood samples were collected after up to 30 minutes of standing on the 7th day of each dietary sodium intervention

• Magnitude of Orthostatic Tachycardia

  Supine and upright heart rates were measured on Day 7 of High Sodium and Low Sodium diet.

• Upright Symptom Score

  Upright symptoms were assessed on the 7th day of diet.

Study Arms (2)

High Sodium Level

EXPERIMENTAL

POTS and healthy controls will be randomly assigned the order of dietary sodium levels. All procedures are performed at both levels. The high sodium diet will provide 300 milliequivalents (mEq) sodium/day.

Radiation: Blood Volume; Radiation: Total Blood Volume; Procedure: Exercise Capacity Test - Bicycle; Procedure: Posture Study

Low Sodium Dietary Level

EXPERIMENTAL

POTS and healthy controls will be randomly assigned the order of dietary sodium levels. All procedures are performed at both levels. The low sodium diet will provide 10 mEq sodium/day.

Radiation: Blood Volume; Radiation: Total Blood Volume; Procedure: Exercise Capacity Test - Bicycle; Procedure: Posture Study

Interventions

Blood Volume RADIATION

we will measure the amount of hemoglobin and myoglobin in the body by a procedure called CO rebreathing. One teaspoon of blood is taken before and after a small amount of CO has been absorbed into the bloodstream.

Also known as: carbon monoxide (CO)-red blood cell (RBC) Blood Volume

High Sodium Level; Low Sodium Dietary Level

Total Blood Volume RADIATION

Using injection of iodinated I-131 tagged human serum albumin nominally 25 microcuries of radiation, blood samples are drawn before and 30 minutes after injection.

Also known as: DAXOR

High Sodium Level; Low Sodium Dietary Level

Exercise Capacity Test - Bicycle PROCEDURE

subjects breath room air through a mouthpiece and exhale the air into a tube that connects to a machine (metabolic cart) that analyzes carbon dioxide and oxygen content, which allows the investigator to calculate the amount of oxygen they are using under resting and exercise conditions.

Also known as: VO2 Max (maximal oxygen consumption)

High Sodium Level; Low Sodium Dietary Level

Posture Study PROCEDURE

Blood pressure and heart rate will be measured while supine and then while standing for up to 30 minutes. Blood will be drawn in each position to measure hormones that regulate blood pressure and blood volume.

Also known as: Standing Orthostatic Challenge

High Sodium Level; Low Sodium Dietary Level

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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
• Age between 18-50 years old
• Non-smokers
• Premenopausal patients with POTS and healthy volunteers
• Only female participants are eligible.
• Since 80-90% of POTS patients are female, and there can be differences in measures with the menstrual cycle, including a small number of males might introduce a significant amount of noise.
• Able and willing to provide informed consent

You may not qualify if:

• Smokers
• Overt cause for postural tachycardia, i.e., acute dehydration
• Significant cardiovascular, pulmonary, hepatic, or hematological disease by history or screening results
• Pregnant (positive pregnancy test) or breastfeeding
• Hypertension defined as supine resting BP\>145/95 mmHg off medications or needing antihypertensive medication
• Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies or an unpredictable schedule
• Unable to give informed consent

Sponsors & Collaborators

• Vanderbilt University: lead
• National Institutes of Health (NIH): collaborator
• National Heart, Lung, and Blood Institute (NHLBI): collaborator

Study Sites (1)

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

Location

Related Publications (2)

• Laurin JKH, Oyewunmi OA, Garland EM, Gamboa A, Nwazue VC, Paranjape SY, Black BK, Okamoto LE, Shibao CA, Biaggioni I, Robertson D, Diedrich A, Dupont WD, Sheldon RS, Raj SR. Adrenal gland response to adrenocorticotropic hormone is intact in patients with postural orthostatic tachycardia syndrome. Auton Neurosci. 2023 Sep;248:103105. doi: 10.1016/j.autneu.2023.103105. Epub 2023 Jun 24.

  PMID: 37393658 DERIVED

• Garland EM, Gamboa A, Nwazue VC, Celedonio JE, Paranjape SY, Black BK, Okamoto LE, Shibao CA, Biaggioni I, Robertson D, Diedrich A, Dupont WD, Raj SR. Effect of High Dietary Sodium Intake in Patients With Postural Tachycardia Syndrome. J Am Coll Cardiol. 2021 May 4;77(17):2174-2184. doi: 10.1016/j.jacc.2021.03.005.

  PMID: 33926653 DERIVED

MeSH Terms

Conditions

Postural Orthostatic Tachycardia Syndrome; Orthostatic Intolerance

Interventions

Blood Volume; Carbon Monoxide; Erythrocyte Count

Condition Hierarchy (Ancestors)

Primary Dysautonomias; Autonomic Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Blood Physiological Phenomena; Circulatory and Respiratory Physiological Phenomena; Hemodynamics; Cardiovascular Physiological Phenomena; Carbon Compounds, Inorganic; Inorganic Chemicals; Gases; Oxides; Oxygen Compounds; Blood Cell Count; Cell Count; Cytological Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Hematologic Tests; Investigative Techniques; Cell Physiological Phenomena

Results Point of Contact

• Title: Alfredo Gamboa, MD
• Organization: Vanderbilt University Medical Center

alfredo.gamboa@vumc.org

6158751003

Study Officials

• Alfredo J Gamboa, MD

  Vanderbilt University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Associate Professor of Medicine

Model Details: Randomization tables will be used to determine whether the 10 mEq sodium/day or 300 mEq sodium/day diet will be consumed first. Both diets will be completed on each subject (randomized crossover study), so all of the study procedures (after screening) will be repeated.

Study Record Dates

• First Submitted: March 2, 2012
• First Posted: March 7, 2012
• Study Start: March 1, 2012
• Primary Completion: December 1, 2020
• Study Completion: December 1, 2021
• Last Updated: February 22, 2022
• Results First Posted: December 8, 2021

Record last verified: 2022-01

Locations

US (1)