Effect of Weight Loss on Myocardial Oxygen Consumption and Left Ventricular Relaxation in Obese Adults
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 51
- Locations
- 2
- Primary Endpoint
- Total Myocardial Fatty Acid (FA) Oxidation
Study Overview
Brief Summary
Obesity adversely affects myocardial (muscular heart tissue) metabolism, efficiency, and diastolic function. The objective of this study was to determine if weight loss could improve obesity-related myocardial metabolism and efficiency and if these improvements were directly related to improved diastolic function.
Detailed Description
This was a prospective, interventional study in obese adults ages 21 to 50 years of age to determine whether weight loss could improve obesity-related myocardial metabolism and efficiency. Two different mechanisms of weight loss were studied: diet and exercise and gastric bypass surgery. Positron emission tomography (PET) was used to quantitate myocardial oxygen consumption (MVO2) and myocardial fatty acid (FA) metabolism. Echocardiography with tissue Doppler imaging was used to quantify cardiac structure, systolic and diastolic function (left ventricular (LV) relaxation (E') and septal ratio (E/E')).
Study Design
- Study Type
- Interventional
- Allocation
- Non Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Basic Science
- Masking
- None
Eligibility Criteria
- Ages
- 21 Years to 50 Years (Adult)
- Sex
- 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
Outcomes
Primary Outcomes
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.
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 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.
Secondary Outcomes
- Mean Body Mass Index(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Mean Homeostasis Model Assessment of Insulin Resistance(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Mean Heart Rate(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Mean Total Serum Cholesterol and Triglycerides(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Mean Arterial Pressure(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Left Ventricular (LV) Relaxation (E')(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Septal Ratio (E/E')(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)
- Left Ventricular (LV) Mass(Measured at baseline, 16 months after gastric bypass surgery-induced weight loss, and 8 months after diet-induced weight loss)