Target Organ Damage and Polymorphisms Vav-2 and Vav-3 in Hypertensive Subjects
Condition: Hypertension
MeSH terms: Hypertension
Study type: Observational

Summary: 
      Objectives: To analyze the influence on the presence of target organ damage renal, cardiac
      and vascular of peripheral and central blood pressure, retinal vessels caliber, oxidative
      stress and polymorphisms of genes VAV-2-3 in hypertensive subjects.

      Methodology: A cross- sectional design we will performed . Population: 486 hypertensive
      patients. Target organ damage will be assessed by tests recommended in 2013 European
      guidelines of hypertension. Blood pressure office and ambulatory, retinal caliber
      vassels,oxidative stress and polymorphisms VAL -2-3 will be measurement.
    

Detailed description: 
      Ambulatory blood pressure monitoring (ABPM): The ABPM will be performed on a day of standard
      activity, with an adequate cuff for the size of the patient's arm. A control system,
      SpaceLabs 90207 model (Spacelabs Healthcare, Issaquah, Washington, USA), validated according
      to the protocol of the British Hypertension Society, will be used [57]. The records in which
      the percentage of valid readings will be 80% of the total and with valid readings at all
      times were considered to be valid. Furthermore, for the records to be evaluable, at least 14
      measurements will be required during the daytime period, or at least seven during the
      nightime or rest period. The monitor will be scheduled for obtaining blood pressure
      measurements every 20 min during the daytime period and every 30 min during the rest period.
      The average and dispersion estimators of SBP and DBP were calculated during the 24-h, daytime
      and nightime periods, defined based on the diary reported by the patient. The patient
      completes a form specifying bedtime and wake-up time.

      Ambulatory arterial stiffness index (AASI) and Home arterial stiffness index (HASI): Arterial
      stiffness will be evaluated by the ambulatory and home arterial stiffness indices (AASI and
      HASI). For AASI and HASI estimation, the regression slope of diastolic on systolic blood
      pressure will be computed for each individual on the basis of 24-hour ABPM (AASI) and also
      HASI readings over 6 days. AASI as well as HASI were defined as one minus the respective
      regression slope of DBP on SBP [58]. AASI will also computed from waking or sleeping blood
      pressure.

      Evaluation of retinal vessels: Retinography will be performed using a Topcon TRC NW 200
      nonmydriatic retinal camera (Topcon Europe B.C., Capelle a/d Ijssel, The Netherlands),
      obtaining nasal and temporal images centered on the disk. The nasal image with the centered
      disk will be loaded into the developed software, AV Index calculator (Ciclorisk SL,
      Salamanca, Spain, registry no. 00/2011/589). The software automatically recognizes the disk
      and draws two external concentric circles which delimit area A, between 0 and 0.5 disk
      diameters from the optic disk margin, and area B, between 0.5 and 1 disk diameters from the
      margin. The software first identifies the limits of the different vessels, after which it
      automatically recognizes arteries and veins, and makes multiple measurements of the diameter
      of the section of the vessels circulating through area B. It finally estimates the mean
      caliber of veins and arteries in mm, and these measurements are summarized as an
      arteriole-venule ratio, AVIx. An AVIx of 1.0 suggests that arteriolar diameters will be on
      average the same as venular diameters in that eye, whereas a smaller AVR suggests narrower
      arterioles. We used the pairs of main vessels in the upper and lower temporal quadrants,
      rejecting all other vessels, to improve reliability and increase efficiency of the process,
      analyzing measures for each quadrant separately and together to estimate the mean measure in
      each eye. [64].

      Laboratory:Determining the concentration of superoxide and catecholamines (adrenaline and
      noradrenaline) in plasma and urine anion will be determined by ELISA (CatCombi ELISA, IBL,
      Deventer, The Netherlands), following the manufacturers instructions. Superoxide dismutase
      activity in plasma will be also assessed using ELISA kits (Cu-Zn superoxid-dismutase ELISA,
      IBL), and the urinary excretion and plasma levels of lipid peroxides by measuring products
      react with thiobarbituric acid (TBARS) (OxiSelect TBARS Assay Kit, Cell Biolabs, Inc., San
      Diego, CA 92126).

      In a sample of DNA from peripheral blood erythrocyte polymorphisms of VAV and VAV-2-3 genes
      in all study subjects are studied. To this end, 10cc of venous blood obtained with
      anticoagulant (EDTA: ethylene diamine tetra-acetic acid).

      Renal assessment: The kidney damage will be assessed by measuring creatinine plasma
      concentration, the glomerular filtration rate was estimated by CKD-EPI (Chronic Kidney
      Disease Epidemiology Collaboration) [59] and the MDRD-IDMS (Modification of Diet in Renal
      Disease-Isotopic Dilution Mass Spectrometry) [60] equation and proteinuria were assessed by
      the albumin/creatinine ratio following the 2007 European Society of Hypertension/European
      Society of Cardiology Guidelines criteria [2]. Subclinical organ damage was defined as plasma
      creatinine between 1.3 - 1.5 mg/dl in men and 1.2 - 1.4 mg/dl in women, glomerular filtration
      rate below 60 ml/min or albumin/creatinine ratio > 22 mg/gr in men and 31 mg/ gr in women.
      Renal disease was defined as plasma creatinine of 1.5 mg/dl or higher in men and 1.4 mg/l in
      women or albumin/creatinine ratio > 300 mg/24 h.

      Cardiac assessment: The electrocardiographic examination will be performed with a General
      Electric MAC 3.500 ECG System (Niskayuna, New York, USA), that measures automatically the
      voltage and duration of waves and estimates the criteria of the Cornell voltage-duration
      product (Cornell VDP) [61] to assess the LVH by the following equation: Men ((RaVL + SV3) *
      QRS) and women ((RaVL + SV3) * QRS + 6). LVH will be defined as the voltage-duration product
      > 2,440 mm/ms [2] and Sokolow and R avl > 11.

      Pulse wave velocity (PWV): These parameters will be estimated using the SphygmoCor System
      (AtCor Medical Pty Ltd., Head Office, West Ryde, Australia). Using the SphygmoCor System (Vx
      pulse wave velocity), and with the patient in the supine position, the pulse waves of the
      carotid and femoral arteries were analyzed, estimating the delay with respect to the ECG wave
      and calculating PWV. Distance measurements were taken with a measuring tape from the sternal
      notch to the carotid and femoral arteries at the sensor location [62].

      Assessment of vascular structure by carotid intima media thickness (IMT): Carotid ultrasound
      to assess C-IMT will be performed by two investigators trained for this purpose before
      starting the study. The reliability of such recordings was evaluated before the study, using
      the intraclass correlation coefficient, which showed values of 0.97 (95%CI: 0.94-0.99) for
      intra-observer agreement on repeated measurements in 20 subjects, and 0.90 (95%CI: 0.74-0.96)
      for inter-observer agreement. According to the Bland-Altman analysis, the limit of
      inter-observer agreement was 0.02 (95% CI: -0.05-0.10), while the limit of intra-observer
      agreement was 0.01 (95% CI: -0.03-0.06). A Sonosite Micromax ultrasound device paired with a
      5-10 MHz multi-frequency high-resolution linear transducer with Sonocal software will be used
      for performing automatic measurements of carotid IMT in order to optimize reproducibility.
      Measurements will be made of the common carotid after the examination of a 10-mm longitudinal
      section at a distance of 1 cm from the bifurcation, performing measurements in the anterior
      or proximal wall, and in the posterior or distal wall in the lateral, anterior and posterior
      projections, following an axis perpendicular to the artery to discriminate two lines: one for
      the intima-blood interface and the other for the media-adventitious interface. A total of 6
      measurements will be obtained of the right carotid, with another 6 measurements of the left
      carotid, using average values (average carotid IMT) and maximum values (maximum carotid IMT)
      automatically calculated by the software [63]. The measurements will be obtained with the
      subject lying down, with the head extended and slightly turned opposite to the examined
      carotid artery. The average IMT will considered abnormal if it measured 0.90 mm, or if there
      will be atherosclerotic plaques with a diameter of 1.5 mm or a focal increase of 0.5 mm or
      50% of the adjacent IMT [2].
    

Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Population: 486 hypertensive patients (20-80 years) will be assessed with all tests
        recommended in 2013 European guidelines of hypertension
      
Biospecimen description: 
      Human biospecimens used will be collected, stored, used, shared, and disposed of in
      accordance with the informed consent signed by the subject, or under a waiver of informed
      consent granted by an independent ethical review body, in accordance to Spanish Law (Ley
      Orgánica de Protección de Datos de Carácter Personal (15/1999 del 13 de Diciembre, LOPD), y
      en las condiciones que marca la Ley 14/2007 de investigación biomédica) of Protection of
      Human Subjects.
    
Keywords: Hypertension; Target organ damage; polymorphism; Hypertensive patients