What’s New in Central Sleep Apnea: Phrenic Nerve Stimulation
Central Sleep Apnea (CSA) is a serious form of sleep disordered breathing with severe consequences for a patient’s quality of life and long-term health. Although CSA can be overshadowed by the more common Obstructive Sleep Apnea (OSA), CSA is a distinct disorder that may require a different treatment pathway and new therapeutic options.
Patients with CSA are often considered difficult to treat. Positive Airway Pressure (PAP) therapies, designed to open the airway and support ventilation, are often used in practice for patients with CSA, but with varying levels of benefit and risk. Other therapies used to treat CSA include oxygen and a range of pharmacological options (acetazolamide, theophylline), although these are also limited in effectiveness and come with some side-effects.
Phrenic nerve stimulation (PNS) is a novel form of therapy designed to treat CSA by sending electric signals to the phrenic nerve. These signals activate the diaphragm, restoring a natural breathing rate and pattern using the body’s own nervous and muscular systems.
Effects of Central Sleep Apnea on Quality of Life and Cardiovascular Health
Central Sleep Apnea (CSA) is characterized by a complete or intermittent lack of neural drive to breathe. Patients with CSA suffer from sleep disruptions and insufficient sleep, evidenced by frequent apneic and hypopneic events, oxygen desaturations, and increased arousals. The frequent arousals and intermittent hypoxia lead to oxidative stress that causes endothelial dysfunction, inflammation and activation of neurohormonal systems, thereby contributing to progression of underlying diseases. These patients are burdened by the daily impact of CSA, including chronic fatigue, excessive daytime sleepiness and cognitive impairment, which substantially reduces quality of life.
Untreated CSA has been associated with significantly higher rates of heart failure and atrial fibrillation. Within the heart failure population, where CSA is most prevalent, CSA has been shown to double the risk of cardiovascular mortality and significantly increase the rate of heart failure hospitalizations.