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

Hemodynamics, Salt Sensitivity and Body Composition in Patients With Morbid Obesity - Effect of Weight Loss Following Laparoscopic Gastric Bypass

Status
Completed
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT00998465
Enrollment
36
Registered
2009-10-20
Start date
2009-11-30
Completion date
2013-01-31
Last updated
2013-03-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Obesity, Hypertension

Keywords

Obesity, Hypertension, Salt sensitivity, Laparoscopic gastric bypass, Bariatric surgery

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.

Interventions

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

OTHEREchocardiography

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

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)

RADIATIONDexa-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.

RADIATIONPlasma volume

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

RADIATIONGlomerular filtration rate (GFR)

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

OTHERBlood samples

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

OTHERUrine analyses

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

DIETARY_SUPPLEMENTDiets 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.

Sponsors

Glostrup University Hospital, Copenhagen
CollaboratorOTHER
Zealand University Hospital
Lead SponsorOTHER

Study design

Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL

Eligibility

Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes

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.

Design outcomes

Primary

MeasureTime frame
Sodium induced change in 24-hour blood pressure before and one year after laparoscopic gastric bypass.One year

Secondary

MeasureTime frame
Echocardiography: Dimensions, systolic and diastolic function before and one year after laparoscopic gastric bypassOne year
Non-invasive hemodynamic measurements (inert gas rebreathing) 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

Countries

Denmark

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026