Effects of Weight Loss on Cardio-respiratory Function

Obesity is a medical problem of epidemic proportions and is associated with high mortality. Obesity has significant effects on the cardiovascular system, producing structural cardiovascular changes including myocardial hypertrophy, fatty infiltration, and fibrosis; diastolic and systolic dysfunction; changes in pulmonary artery compliance; and increased aortic stiffness - all of which can lead to heart failure. Indeed, evidence suggests that obesity increases the risk for heart disease independent of other known risk factors such as coronary artery disease, hypertension, diabetes mellitus, and obstructive sleep apnea. Obesity also causes significant changes in pulmonary function, including a decrease in expiratory reserve volume and functional residual capacity and closure of peripheral airways. The exact mechanisms for the development of cardiopulmonary disease are not well understood - the pathophysiology is complex and likely multifactorial, related to altered hemodynamic load, altered metabolic activity, underlying inflammation, and increased cardiac output. Newer diagnostic modalities available at our institution such as cardiac MRI and pulmonary function tests with impulse oscillometry allow us to better evaluate cardiopulmonary dysfunction in patients with severe obesity. Cardiac MRI is especially promising as a non-invasive imaging modality in obese individuals, providing more reproducible measurements of cardiac and vascular anatomy and function relative to echocardiography. Similarly, pulmonary function testing with impulse oscillometry is more sensitive for detection of abnormalities in the distal airways especially when spirometry is normal, as frequently occurs in the severely obese symptomatic patients. The main objective of the proposed study is to evaluate the effect of obesity on quality of life and health care utilization and its relationship to cardiopulmonary disease in an ethnically diverse, underserved obese population by using state-of-the-ar