Cardiac Hemodynamics in Overlap Syndrome (COPD With Obstructive Sleep Apnea)

Presence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) in the same patient has been termed overlap syndrome, affecting 1% of the U.S. population. Despite the high prevalence of overlap syndrome, little research has been done in this field. Overlap syndrome has been recently reported to have higher death rate than COPD alone, which is due to effect on the heart. However, the mechanisms by which overlap syndrome affects the heart are not known well. Also, the ideal treatment for overlap syndrome is not known. This study is being done to find the mechanisms by which overlap syndrome affects the right and left sides of heart (using cardiac MRI to study the heart). We will also compare the effect of treatment with bi-level positive airway pressure device (BPAP) vs. night-time oxygen on heart in overlap syndrome. These aims will allow us to test the hypothesis that overlap syndrome patients have worse heart function than COPD only or OSA only, and treatment with BPAP device will improve the heart function better than oxygen only. At the baseline visit, the subject will undergo an overnight sleep study in the hospital. In the morning, blood draw to measure serum inflammatory biomarkers (C-Reactive Protein, interleukin-6, P-selectin, ICAM-1, TNF-alpha), urine catecholamine level, six-minute walk test, questionnaire for health-related quality of life score and modified Medical Research Council (MMRC) dyspnea score, lung function tests, ultrasound of forearm blood vessels and cardiac MRI will be done. No follow-up visit is needed if the subject does not have sleep apnea. If the subject has sleep apnea based on the sleep study, he/she will be allotted to treatment with a BPAP device or night-time oxygen for 6 months. If the subject does not want to be treated with BPAP or oxygen, CPAP device will be used to treat sleep apnea. During the duration of study treatment, phone calls and a brief study visit at 3 months will be done to make sure there is no discomfort related to the treatment. After 6 months of study treatment, cardiac MRI, ultrasound of forearm blood vessels, lung function tests, blood draw for serum inflammatory biomarkers, urine catecholamine level, six-minute walk test, and questionnaires for dyspnea score and quality of life score will be repeated. This study will help us in better understanding of mechanisms of high death rate due to effects on the heart in overlap syndrome. It will also help us in understanding better ways to treat sleep apnea in COPD patients.