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

Completed
Conditions
Obesity
Hypertension
Interventions
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
Registration Number
NCT00998465
Lead Sponsor
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.

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.

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
36
Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type
OBSERVATIONAL
Study Design
Not specified
Arm && Interventions
GroupInterventionDescription
ControlDiets with low and high sodium contentControl subjects without hypertension and body mass index \< 30 kg/m2
Obese, hypertensionDiets with low and high sodium contentObese patients with hypertension and a body mass index 40-50 kg/m2
Control24-hour blood pressureControl subjects without hypertension and body mass index \< 30 kg/m2
ControlInert gas rebreathingControl subjects without hypertension and body mass index \< 30 kg/m2
ControlDexa-scanControl subjects without hypertension and body mass index \< 30 kg/m2
ControlPlasma volumeControl subjects without hypertension and body mass index \< 30 kg/m2
ControlGlomerular filtration rate (GFR)Control subjects without hypertension and body mass index \< 30 kg/m2
Obese, hypertension24-hour blood pressureObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, hypertensionDexa-scanObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, normotensionPlasma volumeObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, normotensionUrine analysesObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, normotensionDiets with low and high sodium contentObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, hypertensionBlood samplesObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, normotensionBlood samplesObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, hypertensionEchocardiographyObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, hypertensionPlasma volumeObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, hypertensionUrine analysesObese patients with hypertension and a body mass index 40-50 kg/m2
ControlEchocardiographyControl subjects without hypertension and body mass index \< 30 kg/m2
ControlBlood samplesControl subjects without hypertension and body mass index \< 30 kg/m2
Obese, normotensionEchocardiographyObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, normotensionGlomerular filtration rate (GFR)Obese patients without hypertension and a BMI between 40-50 kg/m2
Obese, hypertensionInert gas rebreathingObese patients with hypertension and a body mass index 40-50 kg/m2
Obese, hypertensionGlomerular filtration rate (GFR)Obese patients with hypertension and a body mass index 40-50 kg/m2
ControlUrine analysesControl subjects without hypertension and body mass index \< 30 kg/m2
Obese, normotensionInert gas rebreathingObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, normotensionDexa-scanObese patients without hypertension and a BMI between 40-50 kg/m2
Obese, normotension24-hour blood pressureObese patients without hypertension and a BMI between 40-50 kg/m2
Primary Outcome Measures
NameTimeMethod
Sodium induced change in 24-hour blood pressure before and one year after laparoscopic gastric bypass.One year
Secondary Outcome Measures
NameTimeMethod
Non-invasive hemodynamic measurements (inert gas rebreathing) before and one year after laparoscopic gastric bypassOne year
Echocardiography: Dimensions, systolic and diastolic function before and one year after laparoscopic gastric bypassOne year
Body composition: Dexa-scan, plasma volume and extracellular volume before and one year after laparoscopic gastric bypassOne year
Blood samples: MR-proANP, p-glucose, p-insulinOne year

Trial Locations

Locations (1)

University Hospital Koege, Department of Clinical Physiology and Nuclear Medicine

🇩🇰

Koege, Denmark

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