The Cardiovascular Consequences of Sleep Apnea Plus COPD (Overlap Syndrome)

Study Summary

Major progress has been made in the area of cardiovascular disease, but we believe that further progress will involve mechanistically addressing underlying respiratory causes including chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA). The most common cause of death in COPD is cardiovascular, although mechanisms are unknown. OSA has been associated with major neurocognitive and cardiovascular sequelae, the latter likely a function of autonomic nervous system abnormalities, oxidative stress, inflammation, and other pathways. Recent data suggest that individuals with OVS die preferentially of cardiovascular disease compared to OSA or COPD alone, although mechanisms are again unclear. The combination of OSA and COPD may lead to profound hypoxemia. Individuals with COPD can develop pulmonary hypertension via disturbances in gas exchange and parenchymal injury leading to loss of pulmonary vasculature. OSA has been associated with mild to moderate pulmonary hypertension, but the situation may be worse if combined with parenchymal lung disease. The biological response to sustained hypoxemia has been carefully studied as has the topic of intermittent hypoxemia; however, to our knowledge, very little research has occurred regarding the combination of sustained plus intermittent hypoxia as seen in OVS. For example, we do not really know whether individuals with OVS develop coronary disease, right or left heart failure, dysrhythmias or some combination of abnormalities predisposing them to cardiovascular death. Thus, design of interventional studies is challenging as causal pathways are poorly understood despite our considerable preliminary data addressing these issues. The purpose of this study is to examine vascular mechanisms in individuals with COPD/OSA overlap syndrome (OVS) compared with matched individuals with obstructive sleep apnea (OSA) alone or chronic obstructive pulmonary disease (COPD) alone and to perform a phase II pilot mechanis

Primary Outcome

Cardiac magnet resonance imaging (CMRI): All subjects will undergo cardiac MRI measurements the same day they undergo the evaluation of vascular reactivity measurements. Supine cardiac MRI imaging will be performed using a 3T MR scanner (GE 750, GE Healthcare) with a 16-element cardiac coil for radiofrequency signal reception. Non-invasive blood pressure will be monitored during cardiac MRI scanning (Dinemap). Standard and novel MRI sequences will be used for myocardial tissue characterization,

Conditions Studied

Interventions

• DEVICE bi-level positive pressure non invasive ventilation
• DRUG Oxygen gas

Study Locations (1)