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

NCT ID: NCT00998465

Last Updated: 2013-03-20

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

36 participants

Study Classification

OBSERVATIONAL

Study Start Date

2009-11-30

Study Completion Date

2013-01-31

Brief Summary

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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

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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.

Conditions

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Obesity Hypertension

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

CROSS_SECTIONAL

Study Groups

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Obese, hypertension

Obese patients with hypertension and a body mass index 40-50 kg/m2

24-hour blood pressure

Intervention Type OTHER

Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night

Echocardiography

Intervention Type OTHER

Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.

Inert gas rebreathing

Intervention Type OTHER

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)

Dexa-scan

Intervention Type RADIATION

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.

Plasma volume

Intervention Type RADIATION

The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.

Glomerular filtration rate (GFR)

Intervention Type RADIATION

GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.

Blood samples

Intervention Type OTHER

p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine

Urine analyses

Intervention Type OTHER

24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.

Diets with low and high sodium content

Intervention Type DIETARY_SUPPLEMENT

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

24-hour blood pressure

Intervention Type OTHER

Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night

Echocardiography

Intervention Type OTHER

Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.

Inert gas rebreathing

Intervention Type OTHER

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)

Dexa-scan

Intervention Type RADIATION

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.

Plasma volume

Intervention Type RADIATION

The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.

Glomerular filtration rate (GFR)

Intervention Type RADIATION

GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.

Blood samples

Intervention Type OTHER

p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine

Urine analyses

Intervention Type OTHER

24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.

Diets with low and high sodium content

Intervention Type DIETARY_SUPPLEMENT

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

24-hour blood pressure

Intervention Type OTHER

Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night

Echocardiography

Intervention Type OTHER

Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.

Inert gas rebreathing

Intervention Type OTHER

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)

Dexa-scan

Intervention Type RADIATION

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.

Plasma volume

Intervention Type RADIATION

The test is performed using 5 MBq technetium-labeled albumine (99mTc-albumine - Vasculosis) with several postinjection samples for accurate zero-time extrapolation.

Glomerular filtration rate (GFR)

Intervention Type RADIATION

GFR and ECV are determined following injection of 3,7 MBq 51Cr-EDTA and postinjection samples three-four hours after injection.

Blood samples

Intervention Type OTHER

p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine

Urine analyses

Intervention Type OTHER

24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.

Diets with low and high sodium content

Intervention Type DIETARY_SUPPLEMENT

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.

Interventions

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24-hour blood pressure

Blood pressure is measured every 15 minutes in the daytime and every 30 minutes at night

Intervention Type OTHER

Echocardiography

Standard 2-D and m-mode echocardiography with determination of dimensions, systolic, and diastolic function.

Intervention Type 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)

Intervention Type OTHER

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.

Intervention Type 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.

Intervention Type 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.

Intervention Type RADIATION

Blood samples

p-glucose, p-insulin, NT-proBNP, hemoglobin, potassium, sodium, creatinine, albumine

Intervention Type OTHER

Urine analyses

24-hour urine collections with determination of u-sodium, u-potassium and u-creatinine.

Intervention Type OTHER

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.

Intervention Type DIETARY_SUPPLEMENT

Eligibility Criteria

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Inclusion Criteria

* 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


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

Exclusion Criteria

* Pregnancy
* Chronic obstructive pulmonary disease
* Diabetes mellitus
* Medical treatment with sibutramine.
Minimum Eligible Age

18 Years

Maximum Eligible Age

70 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Glostrup University Hospital, Copenhagen

OTHER

Sponsor Role collaborator

Zealand University Hospital

OTHER

Sponsor Role lead

Responsible Party

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University Hospital Koege

Principal Investigators

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Peter K Bonfils, MD

Role: PRINCIPAL_INVESTIGATOR

University Hospital Koege

Morten Damgaard, MD, Ph.D.

Role: STUDY_DIRECTOR

Hvidovre Hospital, Copenhagen

Mustafa Taskiran, MD, Ph.D.

Role: STUDY_DIRECTOR

University Hospital Koege

Viggo B Kristiansen, MD

Role: STUDY_DIRECTOR

Glostrup Hospital, Copenhagen

Knud H Stokholm, MD

Role: STUDY_DIRECTOR

University Hospital Koege

Niels Gadsboll, MD, DMSc

Role: STUDY_CHAIR

University Hospital Koege

Locations

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University Hospital Koege, Department of Clinical Physiology and Nuclear Medicine

Koege, , Denmark

Site Status

Countries

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Denmark

References

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Bonfils PK, Taskiran M, Damgaard M, Goetze JP, Floyd AK, Funch-Jensen P, Kristiansen VB, Stockel M, Bouchelouche PN, Gadsboll N. Roux-en-Y gastric bypass alleviates hypertension and is associated with an increase in mid-regional pro-atrial natriuretic peptide in morbid obese patients. J Hypertens. 2015 Jun;33(6):1215-25. doi: 10.1097/HJH.0000000000000526.

Reference Type DERIVED
PMID: 25668345 (View on PubMed)

Other Identifiers

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SJ-99

Identifier Type: -

Identifier Source: org_study_id

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