Relationship of Urine Sodium Excretion to Central Blood Pressure and Aortic Pulse Wave Velocity
Condition: Hypertension
MeSH terms: Hypertension
Study type: Observational

Summary: 
      One interesting area is the relationship of high salt intake and central aortic blood
      pressure. High salt intake is associated development of hypertension and cardiovascular
      mortality. Central aortic pressure is better correlated with cardiovascular events and
      mortality. With recent advances in technology, it is possible to measure central aortic
      pressure noninvasively and easily. Until now there is no study to evaluate the relationship
      of high salt intake and aortic blood pressure.

      The purpose of the present study is to evaluate the relationship of high salt intake and
      aortic blood pressure and aortic stiffness.

      Subjects with or without hypertension will be enrolled for investigation. Subjects with
      hypertension should be never treated with antihypertensive medications. Subjects with
      secondary hypertension, diabetes, heart failure, high grade kidney disease, ischemic heart
      disease, and major arrhythmia will be excluded.

      Sodium intake is measured by 24 hour urinary sodium excretion, with the measurement of
      peripheral and central aortic blood pressure, and aortic pulse wave velocity.

      Salt sensitive hypertension related single nucleotide polymorphism will be analyzed to define
      the relationship with high salt intake and aortic pressure and pulse wave velocity.
    

Detailed description: 
      Measurements: should be performed for 2 days

        1. 24 hour urine Na, K and Creatinine, 24 hour urine amount

             1. Calculation of urine completeness index : Cr/(21 x Bwt)

             2. Definition of complete urine collection: complete index ≥ 0.7 and loss not more
                than one time and 100 mL

        2. Peripheral blood pressure (pBP)

             1. Microlife WatchBP Office

             2. Sitting position

             3. After 5 minutes resting

             4. Peripheral systolic BP (pSBP), Peripheral diastolic BP (pDBP),

        3. Central aortic blood pressure

             1. SphygmoCor (AtCor Medical, Australia)

             2. Central systolic blood pressure

             3. Difference between peripheral SBP and central SBP (SBPp-c)

        4. Pulse wave velocity

             1. VP2000 (Colin, Japan)

             2. Central pulse wave velocity: carotid-femoral Pulse Wave Velocity

             3. Measure by tape

             4. distance from suprasternal notch to carotid artery

             5. distance from suprasternal notch to femoral artery

             6. Silent environment

        5. Blood chemistry and complete blood count

             1. Measure at the morning of second day after overnight fasting

             2. complete blood count, blood urea nitrogen/Creatinine, fasting blood glucose, Total
                cholesterol, Triglyceride, High density lipoprotein cholesterol

        6. 24 hour ambulatory blood pressure measurement

      Measurement protocol

        1. 1st day

             1. Visit hospital before 9:00 AM after overnight fasting

             2. start 24 hour urine collection from 9:00 AM (with education for complete
                collection)

             3. start 24 hour ambulatory blood pressure monitoring, in parallel with 24 hour urine
                collection

        2. 2nd day

             1. Measure central aortic blood pressure

             2. Measure blood Lab

             3. Measure Pulse Wave Velocity

      Analysis of Salt sensitive gene polymorphism

        1. Single Base Extension technology(SBE)

        2. single nucleotide polymorphism rs2398162 and other salt sensitive hypertension related
           single nucleotide polymorphism
    

Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        subjects with or without hypertension
      
Biospecimen description: 
      Serum, Plasma, and DNA sample (whole blood)
    
Keywords: hypertension