A new study holds promise for people with moderate to severe obstructive sleep apnea who are unable to tolerate standard therapy, after finding that an implantable, nerve-stimulating device successfully eased symptoms of the condition.
Lead author Dr. Richard Schwab, co-medical director of the Sleep Center at the University of Pennsylvania School of Medicine, and colleagues recently presented their findings at SLEEP 2016 – the 30th annual meeting of the Associated Professional Sleep Societies LLC, held in Denver, CO.
The condition occurs when the muscles at the back of the throat collapse and close during sleep, blocking airflow. This causes brief and repeated pauses in breathing that last at least 10 seconds.
According to the National Sleep Foundation, OSA can cause sleep disruption and low blood oxygen levels, which can increase the risk of mood and memory problems, high blood pressure, and heart disease.
The first-line treatment for OSA is continuous positive airway pressure (CPAP). This involves the use of a mask that the patient places over their nose and/or mouth during sleep, which prevents breathing pauses by providing a continuous flow of air.
While it is an effective therapy for many patients with OSA, some patients do not respond well to the treatment, highlighting the need for an effective alternative.
In this latest study, Dr. Schwab and colleagues show how a technique called hypoglossal nerve stimulation (HGNS) could fulfill this need.
HGNS is a method in which mild stimulations are delivered to the patient’s hypoglossal nerve – the nerve that controls tongue movement – during sleep, leading to enlargement of the upper airway and improved airflow.
The technique incorporates a battery-powered device consisting of a breathing sensor, a generator, and a stimulation lead. The device monitors the patient’s breathing patterns, and stimulations are delivered to the hypoglossal nerve in response to breathing pauses.
In a previous study – called the Stimulation Therapy for Apnea Reduction (STAR) trial – researchers found that HGNS reduced the number of breathing pauses in patients with OSA by 78 percent, and it reduced the number of low blood oxygen events by 80 percent.
These outcomes remained for 3 years after the device was implanted, the study found.
The results led to HGNS being approved by the U.S. Food and Drug Administration (FDA) in 2014 for the treatment of patients with OSA who do not respond to CPAP.
However, Dr. Schwab and colleagues note that the STAR trial was carried out under controlled conditions. Is HGNS as effective in the real world? This is what the team set out to investigate.
For their study, the researchers analyzed the clinical outcomes of 20 patients with OSA who were fitted with the HGNS device at the University of Pennsylvania between January 2015 and March 2016.
Specifically, they assessed the severity of OSA experienced by each patient before and after the device was implanted, as determined by the total apnea-hypopnea index (AHI), which measures the number of breathing pauses during sleep.
They also measured nighttime oxygen levels in each patient’s blood prior to and after device implantation.
The researchers found that OSA patients experienced an average of 35 fewer breathing pauses an hour after the HGNS device was implanted – representing an 84 percent reduction.
Furthermore, they identified an average 11-percent increase in blood oxygen levels for patients with the lowest levels.
Based on their results, the authors conclude that HGNS is an effective alternative treatment option for patients with OSA who do not respond to CPAP.
“Considering that sleep apnea can lead to high blood pressure, heart attack, stroke, and other serious health problems, it is critically important that we study devices that may serve as another option instead of CPAP to treat patients with sleep apnea.
There is no perfect treatment option for obstructive sleep apnea, but our preliminary data suggest that hypoglossal nerve stimulation can effectively treat patients with sleep apnea who are unable to tolerate CPAP.”
Dr. Richard Schwab