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Hemodynamics, Salt Sensitivity and Body Composition in Patients With Morbid Obesity

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ClinicalTrials.gov Identifier: NCT00998465
Recruitment Status : Completed
First Posted : October 20, 2009
Last Update Posted : March 20, 2013
Sponsor:
Collaborator:
Glostrup University Hospital, Copenhagen
Information provided by:
Zealand University Hospital

Brief Summary:
The purpose of this study is to evaluate the effect of high vs. low sodium intake on blood pressure and system hemodynamics in patients with morbid obesity and to evaluate the impact of laparoscopic gastric bypass on blood pressure, salt sensitivity and body composition in morbidly obese patients. Furthermore, we wants to describe the hemodynamic mechanisms involved in the amelioration of blood pressure during long-term weight loss.

Condition or disease Intervention/treatment
Obesity Hypertension Other: 24-hour blood pressure Other: Echocardiography Other: Inert gas rebreathing Radiation: Dexa-scan Radiation: Plasma volume Radiation: Glomerular filtration rate (GFR) Other: Blood samples Other: Urine analyses Dietary Supplement: Diets with low and high sodium content

Detailed Description:

Overweight and obesity are rapidly increasing in Western countries and are associated with increased mortality and morbidity. The increased morbidity is assumed to be mediated mainly by insulin resistance, diabetes, hypertension and lipid disturbances, but obesity also represents an independent risk factor for cardiovascular disease.

Obesity is associated with an increased risk of hypertension but the pathophysiological basis is not fully established. Several studies have indicated that blood pressure of obese patients could be more dependent on dietary sodium intake than the blood pressure of non-obese patients(as it is the case for patients with essential hypertension)and that this sodium sensitivity of blood pressure is lost after weight loss.

To date, bariatric surgery is the only therapy resulting in substantial and durable long-term weight loss, and the beneficial effects on obesity-related co-morbidities have been well documented. Laparoscopic gastric bypass results in a remarkable improvement of glucose homeostasis and a resolution of diabetes, that typically occurs too fast to be accounted for by weight loss alone. Furthermore, an immediate reduction of blood pressure following laparoscopic gastric bypass has been demonstrated in morbidly obese patients with hypertension as early as one week after the operation. As with the rapid reduction of diabetes, the antihypertensive effect of the procedure might be a consequence of the rearrangement of the gastrointestinal anatomy.

With this study, we want to evaluate the effect of high vs. low sodium intake on blood pressure and system hemodynamics in patients with morbid obesity and to evaluate the impact of laparoscopic gastric bypass on blood pressure, salt sensitivity and body composition in morbidly obese patients. Furthermore, we wants to describe the hemodynamic mechanisms involved in the amelioration of blood pressure during long-term weight loss. Therefore, patients are examined before, 4-6 weeks after and one year after laparoscopic gastric bypass.

Before and one year after the operation, the patients are examined two times; in a five days period of a low dietary sodium consumption and in a five days period of a high sodium consumption respectively. Four-six weeks following the operation, the patients are examined once on their usual diet.

The protocol comprise three sub studies:

  1. The effect of high vs low sodium intake on blood pressure and hemodynamics in the morbid obese patient - preoperative study.
  2. Effect of gastric bypass surgery on blood pressure, hemodynamics and salt-sensitivity - 1 year follow-up.
  3. Effect of gastric bypass surgery on echocardiographic parameters - 1 year follow-up.

Study Type : Observational
Actual Enrollment : 36 participants
Observational Model: Case Control
Time Perspective: Cross-Sectional
Official Title: Hemodynamics, Salt Sensitivity and Body Composition in Patients With Morbid Obesity - Effect of Weight Loss Following Laparoscopic Gastric Bypass
Study Start Date : November 2009
Primary Completion Date : December 2012
Study Completion Date : January 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Allergy Sodium
U.S. FDA Resources

Group/Cohort Intervention/treatment
Obese, hypertension
Obese patients with hypertension and a body mass index 40-50 kg/m2
Other: 24-hour blood pressure
Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night
Other: Echocardiography
Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.
Other: Inert gas rebreathing
Cardiac output, stroke volume and total peripheral resistance are tested at rest and during exercise (bicycle ergometer) using non-invasive equipment (inert gas rebreathing - Innocor)
Radiation: Dexa-scan
Fat mass and fat free mass is determined with a whole body Dexa scan, and bone mineral density is tested with Dexa-scans of the lumbar spine and proximal femur.
Radiation: Plasma volume
The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.
Radiation: Glomerular filtration rate (GFR)
GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.
Other: Blood samples
p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine
Other: Urine analyses
24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.
Dietary Supplement: Diets with low and high sodium content
Participants are subjected to 5 days of low (90 mmol/day) and high (250 mmol/day) sodium intake in a randomized order before and 1 year after laparoscopic gastric bypass surgery.
Control
Control subjects without hypertension and body mass index < 30 kg/m2
Other: 24-hour blood pressure
Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night
Other: Echocardiography
Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.
Other: Inert gas rebreathing
Cardiac output, stroke volume and total peripheral resistance are tested at rest and during exercise (bicycle ergometer) using non-invasive equipment (inert gas rebreathing - Innocor)
Radiation: Dexa-scan
Fat mass and fat free mass is determined with a whole body Dexa scan, and bone mineral density is tested with Dexa-scans of the lumbar spine and proximal femur.
Radiation: Plasma volume
The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.
Radiation: Glomerular filtration rate (GFR)
GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.
Other: Blood samples
p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine
Other: Urine analyses
24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.
Dietary Supplement: Diets with low and high sodium content
Participants are subjected to 5 days of low (90 mmol/day) and high (250 mmol/day) sodium intake in a randomized order before and 1 year after laparoscopic gastric bypass surgery.
Obese, normotension
Obese patients without hypertension and a BMI between 40-50 kg/m2
Other: 24-hour blood pressure
Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night
Other: Echocardiography
Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.
Other: Inert gas rebreathing
Cardiac output, stroke volume and total peripheral resistance are tested at rest and during exercise (bicycle ergometer) using non-invasive equipment (inert gas rebreathing - Innocor)
Radiation: Dexa-scan
Fat mass and fat free mass is determined with a whole body Dexa scan, and bone mineral density is tested with Dexa-scans of the lumbar spine and proximal femur.
Radiation: Plasma volume
The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.
Radiation: Glomerular filtration rate (GFR)
GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.
Other: Blood samples
p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine
Other: Urine analyses
24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.
Dietary Supplement: Diets with low and high sodium content
Participants are subjected to 5 days of low (90 mmol/day) and high (250 mmol/day) sodium intake in a randomized order before and 1 year after laparoscopic gastric bypass surgery.



Primary Outcome Measures :
  1. Sodium induced change in 24-hour blood pressure before and one year after laparoscopic gastric bypass. [ Time Frame: One year ]

Secondary Outcome Measures :
  1. Echocardiography: Dimensions, systolic and diastolic function before and one year after laparoscopic gastric bypass [ Time Frame: One year ]
  2. Non-invasive hemodynamic measurements (inert gas rebreathing) before and one year after laparoscopic gastric bypass [ Time Frame: One year ]
  3. Body composition: Dexa-scan, plasma volume and extracellular volume before and one year after laparoscopic gastric bypass [ Time Frame: One year ]
  4. Blood samples: MR-proANP, p-glucose, p-insulin [ Time Frame: One year ]

Biospecimen Retention:   Samples With DNA

Blood samples: p-glucose, p-insulin, MR-proANP, hemoglobine, sodium, potassium, creatinine, albumine.

Urine collections: u-sodium, u-potassium, u-creatinine



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

The cases are recruited from the Bariatric Clinics at Glostrup Hospital, Koege Hospital and The Private Hospital Hamlet.

Controls are recruited through public advertisement

Criteria

Inclusion Criteria (cases):

  • Caucasians fulfilling the criteria for laparoscopic gastric bypass.
  • 12 participants with hypertension, defined as blood pressure > 140/90 and/or use of antihypertensive medication and 12 participants without hypertension.
  • Body mass index 40-50 kg/m2

Inclusion Criteria (controls):

  • Caucasian.
  • No hypertension or use of antihypertensive medication.
  • Body mass index < 30 kg/m2

Exclusion Criteria (all):

  • Pregnancy
  • Chronic obstructive pulmonary disease
  • Diabetes mellitus
  • Medical treatment with sibutramine.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00998465


Locations
Denmark
University Hospital Koege, Department of Clinical Physiology and Nuclear Medicine
Koege, Denmark, DK-4600
Sponsors and Collaborators
Zealand University Hospital
Glostrup University Hospital, Copenhagen
Investigators
Principal Investigator: Peter K Bonfils, MD University Hospital Koege
Study Director: Morten Damgaard, MD, Ph.D. Hvidovre Hospital, Copenhagen
Study Director: Mustafa Taskiran, MD, Ph.D. University Hospital Koege
Study Director: Viggo B Kristiansen, MD Glostrup Hospital, Copenhagen
Study Director: Knud H Stokholm, MD University Hospital Koege
Study Chair: Niels Gadsboll, MD, DMSc University Hospital Koege

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Peter Kramshoj Bonfils, MD, University Hospital Koege
ClinicalTrials.gov Identifier: NCT00998465     History of Changes
Other Study ID Numbers: SJ-99
First Posted: October 20, 2009    Key Record Dates
Last Update Posted: March 20, 2013
Last Verified: March 2013

Keywords provided by Zealand University Hospital:
Obesity
Hypertension
Salt sensitivity
Laparoscopic gastric bypass
Bariatric surgery

Additional relevant MeSH terms:
Hypertension
Obesity
Hypersensitivity
Obesity, Morbid
Vascular Diseases
Cardiovascular Diseases
Overnutrition
Nutrition Disorders
Overweight
Body Weight
Signs and Symptoms
Immune System Diseases