Implantable Device for Sleep Apnea Therapy?

An implantable device shows promise as a good option for patients who have central sleep apnea (CSA), according to the results of a new study.

“Any patient with moderate or severe sleep apnea with an apnea-hypopnea index of more than 20 that is mostly central in nature would be a good candidate for this implantable device, and could be referred into an ongoing pivotal study. Patients who fit this profile tend to have heart failure (with a reduced or a preserved ejection fraction) or atrial fibrillation, but CSA may affect others, such as those with neurological disorders,” William T. Abraham, MD, Professor of Internal Medicine, Cell Biology, and Physiology at The Ohio State University Wexner Medical Center in Columbus told ConsultantLive.

Dr Abraham also is Chair of Excellence in Cardiovascular Medicine and Director, Division of Cardiovascular Medicine at the center.

Three-fourths of patients with heart failure have sleep apnea, either obstructive or central in about a 50:50 split, so nearly all patients with heart failure should be screened for sleep apnea, Dr Abraham said.

“From 20% to 50% of patients prescribed continuous positive airway pressure (CPAP) therapy do not tolerate it well. When one considers inadequate CPAP treatment, defined as less than 4 hours of adherence per night, the number is closer to 50%,” Dr Abraham stated. “Thus, alternative therapies are needed.”

“Clinically, our preliminary data indicate that heart failure patients feel better with this therapy and there are some physiological markers of improvement too,” he noted. “Ongoing studies will better define the benefits.”

Dr Abraham and other cardiovascular researchers at 11 centers around the world tested the feasibility, safety, and efficacy of a new transvenous phrenic nerve stimulator. The device resembles a pacemaker in that it delivers a regular signal to stimulate the diaphragm via the phrenic nerve to breathe during sleep.

In a pilot study, 47 patients were evaluated at 3 and 6 months after having the device implanted below the collarbone and a transvenous stimulator lead positioned near the phrenic nerve. After a 1-month healing period, the device was turned on and programmed to the patient’s sleep habits.

Researchers saw significant results, including a 56% reduction in overall apnea events per hour and a more than 80% reduction in CSA events.

“The device normalized breathing during sleep, it reduced apnea episodes and, in association with that, we saw improvements in sleepiness symptoms and patients’ quality of life,” Dr Abraham said. “We also noted a reduction in blood pressure in patients with hypertension.”

Now the researchers are comparing the device with current medical therapy for CSA in a larger randomized, controlled clinical trial that will monitor patients for up to 5 years. Dr Abraham noted that the device is being used as first-line therapy in the clinical study, but it also could be used as an alternative in CPAP-intolerant patients.

“An important message for primary care physicians is to have a low threshold for testing for sleep apnea in at-risk populations, such as heart failure patients,” Dr Abraham said. “While 75% of these patients have sleep apnea, nationally fewer than 5% are diagnosed and treated.”

Dr Abraham reported the results of the pilot study at the Heart Failure Society of America's Annual Scientific Meeting.