Effect of Weight Loss on Myocardial Metabolism and Cardiac Relaxation in Obese Adults
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ClinicalTrials.gov Identifier: NCT00572624 |
Recruitment Status
:
Completed
First Posted
: December 13, 2007
Results First Posted
: May 15, 2017
Last Update Posted
: May 15, 2017
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Condition or disease | Intervention/treatment | Phase |
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Obesity | Behavioral: Diet Procedure: Gastric bypass surgery | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 51 participants |
Allocation: | Non-Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Basic Science |
Official Title: | Effect of Weight Loss on Myocardial Oxygen Consumption and Left Ventricular Relaxation in Obese Adults |
Study Start Date : | June 2003 |
Actual Primary Completion Date : | June 2014 |
Actual Study Completion Date : | June 2014 |
Arm | Intervention/treatment |
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Experimental: Diet
Participants who received counseling and instruction about weight loss through diet and exercise
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Behavioral: Diet
Participants attended 20 group behavioral modification sessions led by a behaviorist, a registered dietician, and a physical therapist. The meal plans ranged from 1200 to 1500 kilocalories per day, depending on subject sex and BMI, and were designed to achieve ≤1% body weight loss/week. Participants completed daily food records, and were taught a variety of weight management skills. The exercise component included strength, flexibility, balance, and endurance instruction, gradually increasing to 30 minutes of exercise 5 days/week.
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Experimental: Gastric bypass surgery
Participants who received gastric bypass surgery
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Procedure: Gastric bypass surgery
The same surgeon performed all bypass procedures using standard techniques. A small (~20 ml) proximal gastric pouch was created by stapling the stomach, and a 75-cm Roux-en-Y limb was constructed by transecting the jejunum distal to the ligament of Treitz, and creating a jejunojejunostomy 75 cm distal to the transection.
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- Total Myocardial Oxygen Consumption (MVO2) [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]The evening before an imaging study, all participants were given a meal containing 12 kcal/kg adjusted body weight (=ideal body weight + ((actual body weight-ideal body weight) x 0.25)). Participants fasted until their imaging studies were completed. Myocardial oxygen consumption (MVO2) was measured using positron emission tomography (PET) following injection of 1-^11C-acetate. Total MVO2 was calculated by multiplying the MVO2 measure by left ventricular weight.
- Total Myocardial Fatty Acid (FA) Utilization [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]The evening before an imaging study, all participants were given a meal containing 12 kcal/kg adjusted body weight (=ideal body weight + ((actual body weight-ideal body weight) x 0.25)). Participants fasted until their imaging studies were completed. Myocardial blood flow was measured using positron emission tomography (PET) following injection of ^30O-water. Myocardial fatty acid (FA) utilization was measured using PET after injection of 1-^11C-palmitate. The calculations that describe the relationship between the different measures of myocardial FA metabolism are: FA utilization/gram = blood flow/gram × FA uptake/gram × [average plasma free FA at the time of the 1-11C-palmitate injection]; FA utilization/gram = FA oxidation/gram + esterification/gram. Total fatty acid utilization was calculated by multiplying the fatty acid utilization rate by left ventricular weight.
- Total Myocardial Fatty Acid (FA) Oxidation [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]The evening before an imaging study, all participants were given a meal containing 12 kcal/kg adjusted body weight (=ideal body weight + ((actual body weight-ideal body weight) x 0.25)). Participants fasted until their imaging studies were completed. Myocardial fatty acid utilization was measured using positron emission tomography (PET) after injecting 1-^11C-palmitate. Total fatty acid oxidation was calculated by multiplying the fatty acid oxidation rate by left ventricular weight.
- Left Ventricular (LV) Relaxation (E') [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Immediately following MVO2 measurement, complete two-dimensional, M-mode, and Doppler echocardiographic studies were performed using second harmonic imaging. Left ventricular relaxation (E') was measured at the lateral annulus. All reported measurements represent the average of three consecutive cardiac cycles. A single investigator blinded to all clinical parameters evaluated all echocardiograms.
- Septal Ratio (E/E') [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Immediately following MVO2 measurement, complete two-dimensional, M-mode, and Doppler echocardiographic studies were performed using second harmonic imaging. The early diastolic (E) velocity was measured, left ventricular relaxation (E') was measured at the lateral mitral annulus, and the E/E'(septal) ratio was calculated. All reported measurements represent the average of three consecutive cardiac cycles. A single investigator blinded to all clinical parameters evaluated all echocardiograms. The normal septal ratio from the lateral mitral annulus is <5, a ratio from 5 to 10 is indeterminate, and a ratio of >10 indicates elevated left atrial pressure.
- Left Ventricular (LV) Mass [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Immediately following MVO2 measurement, complete two-dimensional, M-mode, and Doppler echocardiographic study were performed using second harmonic imaging. Left ventricular (LV) mass was measured using the area-length method. All reported measurements represent the average of three consecutive cardiac cycles. A single investigator blinded to all clinical parameters evaluated all echocardiograms.
- Mean Heart Rate [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Heart rate was measured at scheduled physical examinations.
- Mean Arterial Pressure [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Mean arterial pressure was measured at scheduled physical examinations.
- Mean Body Mass Index [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Participant weight and height was measured at scheduled physical examinations. Body mass index was calculated as participant body weight in kilograms divided by their height in meters squared.
- Mean Total Serum Cholesterol and Triglycerides [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]Blood testing was conducted at scheduled times during the study. Serum cholesterol and triglycerides were measured by the enzymatic method (Roche Diagnostics).
- Mean Homeostasis Model Assessment of Insulin Resistance [ Time Frame: Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss ]The homeostasis model assessment of insulin resistance (HOMA) was used to calculate insulin resistance using the first AM, fasting glucose and insulin levels. Plasma insulin levels were measured by radioimmunoassay, and glucose levels were measured by automated hexokinase assay. A HOMA score of <3 represents normal insulin resistance, a score between 3 and 5 moderate insulin resistance, and a score of 5 or higher represents severe insulin resistance.

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Ages Eligible for Study: | 21 Years to 50 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Body mass index (BMI) > 30 kg/m^2
- Sedentary lifestyle
Exclusion Criteria:
- Body weight >159 kg
- Insulin-requiring diabetes
- Heart failure
- History of coronary artery disease
- Chest pain
- Untreated sleep apnea
- Being an active smoker
- Pregnant, lactating, or postmenopausal

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 ClinicalTrials.gov identifier (NCT number): NCT00572624
United States, Missouri | |
Washington University Medical School | |
Saint Louis, Missouri, United States, 63110 |
Principal Investigator: | Robert Gropler, MD | Washington University Medical School |
Publications of Results:
Other Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Washington University School of Medicine |
ClinicalTrials.gov Identifier: | NCT00572624 History of Changes |
Other Study ID Numbers: |
05-0523 (201105066) P01HL013851-43 ( U.S. NIH Grant/Contract ) |
First Posted: | December 13, 2007 Key Record Dates |
Results First Posted: | May 15, 2017 |
Last Update Posted: | May 15, 2017 |
Last Verified: | May 2017 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Keywords provided by Washington University School of Medicine:
Heart Metabolism Obesity Weight loss Gastric bypass surgery Diet and exercise |
Additional relevant MeSH terms:
Weight Loss Body Weight Changes Body Weight Signs and Symptoms |