Implantable device reduces obstructive sleep apnea symptoms
DENVER/PHILADELPHIA, USA: A new implantable device offers promise for patients with moderate to severe obstructive sleep apnea (OSA) who cannot tolerate continuous positive airway pressure (CPAP), the most commonly used treatment for OSA. After a successful initial clinical trial in 2014, involving medical institutions in Europe and the U.S., a new case study conducted by U.S. researchers has now demonstrated that the device notably reduces the symptoms of OSA.
Since the 1980s, CPAP—in which mild air pressure is applied on a continuous basis to keep the airways open—has been the most widely used treatment for OSA. However, many OSA patients are unable to use CPAP owing to discomfort or other problems. In order to help these patients, Inspire Medical Systems has developed the Inspire Upper Airway Stimulation device, which is implanted in the upper chest.
In the surgery, a stimulator is positioned near the clavicle and connected to a stimulation electrode placed on the hypoglossal nerve, which controls tongue motion. Moreover, the stimulator is connected to a pressure sensor between the rib muscles to detect breathing effort. After determining the user’s breathing pattern, the device stimulates the hypoglossal nerve, which enlarges and stabilizes the upper airway and thereby improves control of breathing. Patients use a remote control to turn the device on and off, so that it is only in use when they sleep.
In the current study, researchers from the Perelman School of Medicine at the University of Pennsylvania examined 20 patients who received the implant between January 2015 and March 2016. The study participants were typically overweight, middle-aged and had severe OSA. All patients underwent a baseline polysomnogram and a polysomnogram approximately two months after the device was implanted, to assess the severity of their apnea and any change after treatment.
According to the researchers, the total score on the apnea–hypopnea index, which measures the severity of sleep apnea by counting the number of pauses in breathing during sleep, significantly decreased for all patients after the device was implanted, with an average of 35 events per hour. This corresponds to an average reduction of 84 percent. Additionally, the lowest oxygen level measured in the blood during the night increased significantly, from 79 percent to 90 percent.
The previous clinical trial, which led to Food and Drug Administration approval of the device in April 2014, was conducted under controlled conditions. According to the researchers, the current study takes the next step by looking at outcomes in post-approval clinical use of the device. By replicating the success of the clinical trial, the findings show that the device is as effective in the general clinical population as it was in participants that met the previous clinical trial criteria, they stated.
“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,” said lead author Dr. Richard Schwab, Professor of Medicine at the Hospital of the University of Pennsylvania and Co-Medical Director of the Penn Sleep Center at 3624 Market Street. “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.”
The researchers presented the results of their study at SLEEP 2016, the 30th annual meeting of the American Academy of Sleep Medicine and the Sleep Research Society, which was held from June 11 to 15 in Denver.