Central sleep apnea and cardiovascular disease state-of-the-art.

Central sleep apnea, a rare polysomnographic finding in the general population, is prevalent in certain cardiovascular conditions including systolic and diastolic left ventricular dysfunction, atrial fibrillation, coronary artery disease, carotid artery stenosis, stroke, and use of certain cardiac-related medications. Polysomnographic findings of central sleep apnea with adverse cardiovascular impacts include nocturnal hypoxemia and arousals, which can lead to increased sympathetic activity both at night and in the daytime. Among cardiovascular diseases, central sleep apnea is most prevalent in patients with left ventricular systolic dysfunction; a large study of more than 900 treated patients has shown a dose-dependent relationship between nocturnal desaturation and mortality. Multiple small randomized controlled trials have shown mitigation of sympathetic activity when central sleep apnea is treated with nocturnal oxygen, continuous positive airway pressure, and adaptive servoventilation. However, two early randomized controlled trials with positive airway pressure devices have shown either a neutral effect on survival or excess premature mortality in the active treatment arm, compared to untreated central sleep apnea. In contrast, the results of the most recent trial using an advanced adaptive servoventilation device showed improved quality of life and no signal for mortality suggesting that treatment of central sleep apnea was at least safe. In addition to positive airway pressure devices, multiple medications have been shown to improve central sleep apnea, but no long-term trials of pharmacologic therapy have been published. Currently, phrenic nerve stimulation is approved for the treatment of central sleep apnea, and the results of a randomized controlled trial showed significant improvement in sleep metrics and quality of life.