Effect of Gastric Bypass-induced Weight Loss on Myocardial Structure, Function and Metabolism

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00841009
Recruitment Status : Completed
First Posted : February 11, 2009
Last Update Posted : May 4, 2016
Information provided by (Responsible Party):
Washington University School of Medicine

Brief Summary:
Obesity affects more than 43 million Americans and is associated with an increased incidence of heart failure, sudden death, and cardiovascular death. We have shown that increasing obesity is independently associated with potentially detrimental LV structural and functional, and metabolic changes. Thus in order to increase our understanding of the effect of obesity on the heart, we wish to study the effect of significant weight loss on these parameters.

Condition or disease
Obesity Gastric Bypass

Detailed Description:

Thirty obese patients who weigh <350#, the weight limit of the PET table, who are to undergo gastric bypass will be enrolled in this study. Written, informed consent approved by the Institutional Review Board of Washington University School of Medicine will be obtained from each subject before his/her participation in this study. Subjects will be compensated for their time. Subjects will undergo Medical Screening (Visit 1) consisting of a comprehensive medical evaluation: a history (questionnaire), physical examination, EKG, blood chemistries, kidney function, complete blood count, lipid profiles and pregnancy tests for women of childbearing age. Subjects who weigh < 300# will have fat-free mass (body composition) determined by using a machine called DEXA. Measurement of Insulin Resistance (Visit 2): Subjects will undergo a hyperinsulinemic/euglycemic clamp and nonradiolabeled glucose infusion in order to define their level of insulin resistance and total body glucose turnover. This study will be performed in the GCRC.

Measurement of Myocardial Metabolism, Efficiency, Structure, and Function Measures and Total Body Fatty Acid Metabolism (Visit 3): Subjects will be admitted to the GCRC the evening before the PET imaging and at 6 pm will receive a standard meal. The next morning an 18-gauge intravenous catheter will be inserted into your arm vein. A catheter (small tube) will also be placed in the radial artery for the total body fat metabolism measurements & for blood pressure monitoring. If the subject wishes it, they may have a Foley placed for urination during the PET scan studies. Myocardial PET imaging. Studies will be performed during fasting conditions at 8 am and ending at 1:00 pm. Each subject will be positioned within the scanner, and a 2-min data collection will be acquired to verify proper positioning before a 5-min. scan will be performed for generation of attenuation correction factors. Heart blood flow, oxygen consumption, and measures of fat metabolism will be obtained using PET imaging after the sequential injections of radiolabeled tracers as reported previously by our group. Blood pressure and heart rate will be monitored continuously and recorded throughout the image acquisition. During the scans, 5 blood samples (0, 2, 10, 20,& 30 min) will be obtained for measurement of hormones, heart fuels (e.g. fats, lactate) and carbon dioxide levels.

Anonymous Genetic Tissue and Data Sampling: Draw and store 1 tablespoon of subject's blood, for a period of up to 10 years, to be used in future studies for screening for differences in genes related to heart membrane proteins or heart energy metabolism (including but not limited to genes known as KV1.5, KV2.1, PPAR, FATP, ACS, PGC-1). Echocardiography: Immediately following the PET imaging for oxygen consumption determination, subjects will undergo a complete 2D-, 3D-, and Doppler echocardiographic examination. Optison or Definity, depending on availability, clinically used intravenous contrast agents may be administered to aid with the acquisition of the ultrasound images. Total body fatty acid metabolism measurements: Simultaneous with the PET imaging, the subjects will undergo an infusion of a tracer amount of nonradioactive fat for measurement of total body fat metabolism. Blood samples will be drawn at predetermined times for this measurement.

3 Months s/p Gastric Bypass Surgery (Visit 4). Blood sampling

1 Year s/p Gastric bypass Measurement of Body Composition, Blood Chemistries, Lipid Levels, and Insulin Resistance (Visits 5 and 6). After the subjects have undergone gastric bypass for clinical reasons and are weight stable for 2 weeks (after approximately 1 year post-gastric bypass).

Study Type : Observational
Actual Enrollment : 18 participants
Observational Model: Case-Crossover
Time Perspective: Prospective
Official Title: Effect of Gastric Bypass-induced Weight Loss on Myocardial Structure, Function and Metabolism
Study Start Date : July 2005
Actual Primary Completion Date : May 2012
Actual Study Completion Date : June 2014

Resource links provided by the National Library of Medicine

Primary Outcome Measures :
  1. measure the effect of marked weight loss induced by gastric bypass surgery on myocardial metabolism, efficiency, structure, and function in morbidly obese men and women [ Time Frame: measure at year 5 ]

Secondary Outcome Measures :
  1. evaluate the relationship between changes in myocardial lipid metabolism with changes in whole-body lipid metabolism caused by weight loss [ Time Frame: measure at year 5 ]

Biospecimen Retention:   Samples With DNA
2 tubes of blood (1 tablespoon total) will be collected (with permission), tested and stored for a length of time

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients who are to undergo gastric bypass surgery

Inclusion Criteria:

  • Subjects that will undergo gastric bypass surgery will be included in the study.

Exclusion Criteria:

  • Subjects who have a history of insulin-requiring diabetes, ≥Class II hypertension, cardiac disease, major systemic disease, of smoking cigarettes with in the last 12 months, who are pregnant or taking vasoactive or lipid-lowering medications will be excluded because these conditions may affect our cardiac endpoints. Subjects unable to give informed consent will be excluded. Subjects > 350# (the weight limit of the PET table) will be excluded.

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 identifier (NCT number): NCT00841009

United States, Missouri
Washington University in St. Louis
St. Louis, Missouri, United States, 63110
Sponsors and Collaborators
Washington University School of Medicine
Principal Investigator: Linda Peterson, MD Washington University School of Medicine

Responsible Party: Washington University School of Medicine Identifier: NCT00841009     History of Changes
Other Study ID Numbers: 05-0523
First Posted: February 11, 2009    Key Record Dates
Last Update Posted: May 4, 2016
Last Verified: May 2016

Keywords provided by Washington University School of Medicine:
gastric bypass

Additional relevant MeSH terms:
Weight Loss
Body Weight Changes
Body Weight
Signs and Symptoms