Perspective:

This review highlights current data on sleep apnea, including associated risks and management. In summary:

1. The prevalence of moderate sleep apnea (apnea-hypopnea index [AHI] >15) is between 1-14%, and one in five adults will have at least mild sleep apnea (AHI >5).

2. The risk for obstructive sleep apnea (OSA) increases with increasing body weight, tobacco use, increasing age, diabetes, alcohol use, and sedative use.

3. Central sleep apnea, also known as Cheyne-Stokes breathing, results in an enhanced chemoreceptor response to PaCO₂ leading to large, sudden drops in PaCO₂ below apneic thresholds, provoking apneas. It is common in heart failure (HF) and stroke patients.

4. Sleep apnea can lead to stimulation of the sympathetic nervous system, and can cause reactive pulmonary hypertension and high reactive oxygen species levels from hypoxia.

5. Sleep apnea is correlated with hyperlipidemia, hypertension, and nonalcoholic steatohepatitis, but these associations are confounded by obesity in the population.

6. In patients with coronary artery disease, sleep apnea is associated with a 10.7% absolute increase in death, cerebrovascular events, and myocardial infarctions. It is unknown if treatment of sleep apnea definitively reduces risk or reduces angina burden.

7. Sleep apnea is associated with atrial fibrillation, bradyarrhythmias, and ventricular arrhythmias, and patients with OSA are at increased risk for sudden death. Small studies suggest that electrical benefit may be gained from continuous positive airway pressure (CPAP) therapy.

8. Sleep apnea prevalence is 47-76% in patients with systolic and diastolic HF and the treatment of sleep apnea may improve HF symptoms and quality of life. Evidence showing impact of therapy on HF mortality, readmission, etc., is lacking.

9. The development of pulmonary hypertension is not solely related to the severity of sleep apnea. CPAP may have some benefit in reducing pulmonary pressures.

10. The gold standard for diagnosis is monitored polysomnography, but ambulatory systems have been devised with variable sensitivity and specificity.