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