Bariatric Surgery, Arterial Stiffness and Target Organ Damage Study (BASTOD)
Condition: Hypertension; Obesity
MeSH terms: Hypertension
Study type: Observational

Summary: 
      Introduction:

      Obesity is a major public health problem, associated with many morbidities, including
      metabolic and cardiovascular disease (CVD). High blood pressure (hypertension) is the most
      common comorbidity and one of the major risk factors for CVD and kidney failure. It has been
      described an almost linear relationship between body mass index (BMI) and the level of blood
      pressure (BP), but the mechanisms underlying this relationship are complex and incompletely
      understood : activation of renin-angiotensin-aldosterone and sympathetic nervous systems,
      alterations in systemic hemodynamics and arterial parameters; a significant correlation
      between overall and / or visceral obesity and arterial stiffness assessed by carotid-femoral
      pulse wave velocity (PWV) has been observed.

      By its effectiveness in terms of magnitude and sustainability of weight loss, bariatric
      surgery is becoming increasingly important in the management of obesity and the prevention of
      its comorbidities. It reduces all-cause as well as CV mortality. Bariatric surgery allows a
      resolution of the metabolic syndrome (in 2 out of 3 patients) and diabetes (in 5 out of 6
      patients), but its effect on blood pressure remains inconstant and transient. The reasons for
      this limitation and the detailed effects of bariatric surgery on hemodynamics and arterial
      parameters have been poorly studied. Of note, a reduction in left ventricular hypertrophy, an
      improvement in diastolic dysfunction and aortic distensibility assessed by ultrasound or MRI
      have been observed.
    

Detailed description: 
      Objective:

      The study aims to (a) estimate the effects of bariatric surgery on the function of large
      arteries (determined non-invasively by measurement of PWV, pressure central reflection
      wavelength) in a population of obese grade 2 or 3, and (b) evaluate the respective role of
      weight loss, the change in metabolic parameters, and the decline in BP on changes in the
      function of large arteries and on markers of target organ alterations after surgery.

      Methods:

      This is a prospective longitudinal study with assessment of arterial stiffness before and
      after 6 and 12 months following bariatric surgery. Ninety grade 2-3 obese patients with an
      indication of bariatric surgery will be included. Arterial stiffness is estimated by the
      aortic PWV (SphygmoCor®) at baseline and after 6 and 12 months following surgery. Changes in
      the central pressure, wave reflection, the PA device, and markers of target organ alteration
      (left ventricular mass, LVM, glomerular filtration rate, GFR, urinary albumin excretion, EUA;
      caliber of retinal vessels as assessed by retinography) will be the secondary objectives.

      To study the evolution of PWV in connection with weight loss, a linear mixed model is used
      based on data collected for each patient every time. Correlations between different
      parameters will be studied each time. Changes in secondary endpoints over time will be
      correlated to changes in weight, BMI, percentage loss of excess weight and blood pressure.

      Expected results and their prospects:

      Weight loss surgery should lead to a rapid and sustained weight loss, improved arterial
      function parameters (BP, arterial stiffness) and markers of target organ damage (GFR, UAE,
      LVM, caliber of retinal vessels).

      The analysis of the relation between the metabolic / hemodynamic responses and target organ
      damage should enable us to identify consistent pathophysiological mechanisms, and refine our
      understanding of the consequences of bariatric surgery.
    

Intervention name(s): Bariatric surgery (Roux-en-y bypass or sleeve gastrectomy)
Intervention type(s): Procedure
Intervention description(s): Bariatric surgery
Other intervention name(s): Roux-en-y bypass; sleeve gastrectomy
Sampling method: Non-Probability Sample
Study population: 
        obese patient candidate for bariatric surgery
      
Keywords: Hypertension; Arterial stiffness; Obesity; Bariatric surgery