How a sleep apnea implant may lower your heart disease risk


New treatments like the hypoglossal nerve stimulator procedure are providing effective alternatives to common sleep apnea treatments, like using a CPAP machine.

Sleep apnea causes more than disrupted sleep for people and their partners. There’s increasing evidence that the disorder also raises the risk for heart diseases such as cardiac arrhythmia (irregular heartbeat), high blood pressure (hypertension), stroke, and sudden death.

The first treatment we try in sleep apnea cases usually is CPAP, or continuous positive airway pressure. But the face mask, hose, and machine can be cumbersome and uncomfortable to sleep in, which leads to many patients not sticking to its use.

Now there’s an alternative procedure I offer to my patients: the hypoglossal nerve stimulator. This is a device we implant in a minimally invasive surgical procedure, and it can help people sleep and breathe easier without masks or hoses. As of March 2017, we are one of just 100 locations worldwide that offers the hypoglossal nerve stimulator procedure.

Sleep apnea basics

According to the National Sleep Foundation, more than 18 million Americans have sleep apnea. Research indicates that sleep apnea and heart disease are linked because of higher-than-normal negative pressure – the pressure when you breathe in – that occurs in people with obstructive sleep apnea, or OSA. When your airway is blocked, as is the case in OSA, the negative pressure increases as you continue to struggle to breathe. This negative pressure is relieved by a “micro” awakenings that relieves the blockage so you can breathe. This pressure may put additional strain on the right side of the heart. We also believe sleep apnea can cause adrenergic surge – a flood of adrenaline in the body – which can cause high blood pressure over time.

When we suspect someone may have sleep apnea, we order a sleep study to gather information about what the patient experiences during sleep. Dr. Won Lee, Clinical Director of our Sleep and Breathing Disorders Clinic, and his team conduct sleep studies for our patients.

If Dr. Lee’s team determines that a person has sleep apnea, they work with the patient to treat the condition with positive airway pressure – applying positive pressure through the nose and mouth during sleep. CPAP is the usual choice, and most patients have to try it before we consider a surgical option.

In many cases, CPAP works wonderfully. However, even if CPAP works, that doesn’t mean people will use it. One study showed that the long-term compliance rate with CPAP is just 54 percent. Going off CPAP therapy without a doctor’s recommendation can lead to a rapid return of sleep apnea symptoms, as well as increased blood pressure and heart rate.

But CPAP isn’t a good option for everyone. Some people have such severe claustrophobia that they can’t tolerate wearing a mask to sleep, and some people physically can’t use the CPAP machine because of their pattern of airway obstruction. If the airways are too collapsed, the CPAP machine may not be able to force air through to the lungs. These patients may be candidates for surgical treatment.

Traditional sleep apnea surgeries to reduce heart disease risk

We’ve had surgical procedures available to treat sleep apnea for many years. These include:

  • Hyoid advancement, also known as hyoid suspension, a procedure to secure the hyoid bone and the attached muscles to a more frontward position in the neck
  • Tonsillectomy, or surgery to remove the tonsils
  • Uvulopalatopharyngoplasty, also known as UPPP, a procedure that widens the airway by removing extra tissue in the throat
  • Maxillomandibular advancement, a procedure to bring the lower jaw forward
  • Base of tongue reduction, a procedure to reduce the bulk of the muscular tongue base

These surgeries can be painful. I tell my tonsillectomy patients that it’s the worst sore throat they’ve had in their lives, and they’ll be feeling it for two weeks.

With traditional surgeries, there’s an upper limit to what I can accomplish for my patients. In a UPPP, for example, I can take away only so much tissue. If I remove too much, the patient could end up with a condition called velopharyngeal insufficiency, or VPI. This can cause problems with breathing, speaking, and swallowing. And there’s the consideration of effectiveness even if there are no problems with these surgeries. Procedures that work on multiple levels more effectively treat the disease.

That’s where the hypoglossal nerve stimulator comes in.

What is the hypoglossal nerve stimulator?

The hypoglossal nerve stimulator is an implantable device that the Food and Drug Administration (FDA) approved in 2014 for use in treating OSA. It has three components:

  • An implantable pulse generator, or IPG – a small computer and battery that we implant in the chest
  • Electrodes that we implant under the skin in the area beneath the chin
  • A sensor in the chest that syncs the device to breathing pattern

The hypoglossal nerve stimulator doesn’t use forced air of any kind. Instead, it stimulates the muscles you use to stick out your tongue. This opens up the airways, causing sleep apnea patients to bring in more air with their natural breathing while they sleep, potentially reducing the risk for adrenal surge and added right-heart strain.

As of March 2017, I’m the only doctor at UT Southwestern who provides the implantation of hypoglossal nerve stimulators. 

How does the process work?

After we implant the device, we let the patient heal for a month. Then the patient has an appointment with the Sleep and Breathing Disorders Clinic team. They’ll turn the stimulator on for the first time and let the patient get used to the tongue stimulation. Though it might seem strange to get used to your tongue moving on its own in the middle of the night, all my patients have begun therapy and continue to tolerate it well without any complaints.

Next, the sleep disorders team will give the patient a range of stimulation for the device so they can work their way up to the most effective level slowly. The patient turns the device on at home before bed and turns it off after waking up.

One or two months after the first visit, the sleep disorders team will schedule a sleep study to make sure the device is working properly and that it doesn’t need further adjustment. Most patients are first-time responders, meaning we don’t need to do much more to the device other than turning it on and turning it up. That’s one differentiator of this procedure from traditional surgeries: There is room for us to adjust the device after surgery if it doesn’t work right away.'

The IPG has a lifespan of about 10 years. Though no patient has yet had a hypoglossal nerve stimulator for 10 years because the procedure is so new, replacing the IPG is similar to replacing a pacemaker battery. It’s a simple 20-minute surgery. We make a small incision to remove the IPG, insert a new one, reconnect the electrodes, and close the incision.

Who is a good candidate for the hypoglossal nerve stimulator?

According to the guidelines set at the time of the device’s FDA approval, patients who get the hypoglossal nerve stimulator should:

  • Be at least 22 years old
  • Have a body mass index, or BMI, less than 32
  • Have a score between 20 and 65 on the apnea hypopnea index (AHI), the number of breathing events associated with OSA per night
  • Not have more than 25% central sleep apnea (caused by the brain not sending proper signals to the muscles that control breathing) or mixed sleep apnea (a combination of obstructive and central sleep apnea)

The hypoglossal nerve stimulator isn’t right for everyone. For instance, patients who have to get magnetic resonance imaging (MRI) scans on a regular basis for brain tumors, chronic back pain, or other conditions shouldn’t get the device. As of March 2017, the device isn’t safe for use with large magnets, such as those in MRI scanners.

Before any patient has the device implanted, I perform a sleep endoscopy. During this procedure, the patient goes to sleep, and I pass a long, thin tube called an endoscope through the patient’s nose to check the airway for patterns of collapse. If a patient has complete concentric collapse, or a total blockage in the area behind the roof of the mouth, that’s a significant sign that the hypoglossal nerve stimulator won’t be effective. In that case, we can consider one of the traditional surgeries to reduce the risk of complications with sleep apnea and cardiovascular disease.

Excellent patient results with the hypoglossal nerve stimulator

We’ve seen tremendous results from patients who have used the hypoglossal nerve stimulator. The Stimulation Therapy for Apnea Reduction (STAR) Trial Group initially tested the device. In their trial, two-thirds of participants saw a 68 percent reduction in the median AHI. Since the FDA’s approval of the device, we’ve seen some centers report 95 or 100 percent success rates in AHI reductions.

Compared to the traditional treatment of CPAP, we’ve seen better reductions in patients’ AHI and oxygen desaturation index, or ODI, levels after they’ve gotten the hypoglossal nerve stimulator. We’ve also seen better reductions in overall quality of life and their levels of sleepiness. Patients with the device have seen sleepiness measurements near the normal levels for people who don’t have sleep apnea.

And we’ve seen much better compliance with the hypoglossal nerve stimulator. The minimum we recommend using CPAP to reduce the risk of heart disease is four hours per night. In one study, researchers found people who used the hypoglossal nerve stimulator did so for an average of 5.8 hours per night – longer on average than people who use CPAP. And because the hypoglossal nerve stimulator is more comfortable, patients tend to stick with it, which increases its potential benefits over time for reducing heart disease risk.

These are amazing results, which is why we’re excited to offer this technology to our patients. One of the main manufacturers of the hypoglossal nerve stimulator, Inspire Medical Systems, is working with a select number of sites performing the surgery so we can continue to carefully evaluate how it works and whom the procedure can help. To share our results and talk about the current status of this exciting new treatment, I spoke about this topic on March 9, 2017, to fellow medical doctors and sleep researchers at the 2017 Circadian and Sleep Medicine Research and Clinical Care Symposium, hosted at our Peter O’Donnell Jr. Brain Institute.

We really are in the infancy of this technology, but it’s something that doctors like me are very excited about. The potential for what we can achieve for our patients’ health is still out there waiting to be explored. I’m hopeful that we can harness that potential for the benefit of patients all over the world.

Take the next step for better sleep and heart health

If you haven’t had a sleep study, but you think you might have sleep apnea, call the Sleep and Breathing Disorders Clinic at 214-645-5337. We need the results of a sleep study before we can recommend any treatment relating to sleep apnea.

If you’ve had a sleep study, and you’re interested in alternatives to CPAP and other sleep apnea treatments, call my office at 214-645-8898 to schedule an appointment.