Vascular Effects of Dietary Salt in Humans With Salt-Resistant Blood Pressure

Study Overview
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Brief Summary
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The purpose of this study is to determine the effects of dietary salt restriction on central hemodynamics and vascular function in men and women with salt resistant blood pressure.

Detailed Description
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Cardiovascular disease remains a major Public Health problem and is the leading cause of death in the US. Dietary sodium restriction is considered an important lifestyle modification for individuals with hypertension; however, there is controversy about the effects of dietary salt given that many individuals do not have salt sensitive blood pressure. Deleterious effects of salt on the vasculature may explain the finding that chronic DSR reduces the cardiovascular event rate by 25%despite only minor reductions in BP. It is not known whether dietary sodium restriction improves central pulsatile hemodynamics, known to be related to the development of left ventricular hypertrophy and heart failure risk, and whether the hypothesized improvements in central hemodynamics are similar in men & women. The purpose of this study is to determine the effects of dietary sodium restriction through dietary counseling on central hemodynamics and vascular function in men and women with salt resistant blood pressure.

Official Title
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Vascular Effects of Dietary Salt in Humans With Salt-Resistant Blood Pressure: Dietary Counseling Study

Conditions
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Healthy

Intervention / Treatment
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* Other: Dietary Sodium Restriction
* Other: Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Habitual dietary sodium intake > 3400mg per day Exclusion Criteria: Abnormal resting ECG Current abnormal blood panel (assessed by comprehensive metabolic panel, lipid panel and complete blood count). Hypertension (currently taking anti-hypertensive medications or resting blood pressure >140/90 mmHg) Medical history of cardiovascular disease, malignant cancer, diabetes or kidney disease Obesity (Body Mass Index > 30) Current pregnancy Unable to provide consent

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dietary Sodium Restriction<br>Daily habitual dietary sodium intake < 2000mg | Other: Dietary Sodium Restriction<br>* A registered dietician will counsel participants to reduce daily habitual dietary salt intake below 2000mg over 4 weeks<br>|
| Sham Comparator: Control<br>Routine habitual dietary sodium intake >3400mg | Other: Control<br>* Participants will consume their routine habitual dietary sodium intake > 3400mg per day with regular pre determined check in phone calls from a registered dietician.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reflected Pulse Wave Amplitude | Late systolic pulsatile load on the left ventricle represented by reflected pulse wave amplitude; assessed by echocardiography combined with applanation tonometry. | Change from baseline at 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Microvascular Function | Cutaneous microvascular dilatory response to local heating assessed by laser Doppler flowmetry coupled with intradermal microdialysis | Change from baseline at 4 weeks | 
| Conduit Artery Endothelial Dependent Dilation | Brachial artery flow mediated dilation assessed by duplex ultrasound | Change from baseline at 4 weeks | 
| Arterial Stiffness | Carotid - Femoral pulse wave velocity assessed by applanation tonometry | Change from baseline at 4 weeks | 
| Forward pulse wave amplitude | Central hemodynamic assessment of the forward pulse wave amplitude assessed by echocardiography combined with applanation tonometry. | Change from baseline at 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Endothelium, vascular, Cardiovascular Disease, Hemodynamics, Oxidative Stress, Dietary Sodium, Dietary Counseling