Effects of Nocturnal Nasal Oxygen on Biomarkers in Sleep Apnea Patients With Heart Failure

Sleep apnea syndrome is clinically defined by frequent pauses in breathing during sleep and
symptoms, such as being tired. It can decrease the restfulness of sleep and decreases the
level of oxygen in the blood. Sleep apnea patients suffer from daytime sleepiness,
hypertension, coronary artery disease (CAD), stroke, ischemic heart disease, arrhythmias,
pulmonary hypertension, heart failure, and premature death. There is significant evidence
suggesting that nighttime decreases in blood oxygen levels are the primary cause of many of
the abnormalities associated with this disease.

Epidemiological studies have demonstrated a surprisingly high prevalence of sleep apnea.
Mild sleep apnea is present in 17% of adults in the general population and moderate to
severe sleep apnea is present in 5.7% of adults. Among patients with heart failure the
prevalence skyrockets. Multiple studies have found the prevalence of moderate to severe
sleep apnea to be anywhere from 11-53% in heart failure patients.

Continuous positive airway pressure (CPAP) therapy is currently the standard of care for
sleep apnea sufferers regardless of the severity of their disease. In patients without heart
failure, CPAP therapy has numerous benefits and several long term studies have reported that
CPAP causes less cardiovascular disease as well as a long term improvement in cardiovascular
symptoms and mortality among patient with severe sleep apnea.

In heart failure patients, CPAP has shown some beneficial short term effects but evidence of
long term improvements in symptoms and mortality are lacking. Compliance with CPAP therapy
reduces systolic blood pressure, improves cardiac function, raises oxygen levels, and
increases exercise tolerance. On the other hand, CPAP has not been shown to affect survival
or number of hospitalizations in heart failure patients. Moreover, compliance with CPAP is
often poor and many people cannot tolerate it. This further limits the therapeutic
effectiveness of this intervention.

The purpose of this study is to assess whether nocturnal oxygen administration via nasal
cannula alone can improve outcomes in congestive heart failure patients with moderate to
severe sleep apnea. The effects of nocturnal oxygen administration will be assessed by using
biomarkers of heart stress and markers of whole body inflammation.