“Central sleep apnea affects more
than a third of heart failure patients and is known to make the condition
worse,” Abraham said. “Unfortunately, we don’t have good treatments available
for this type of apnea. Currently, positive airway pressure devices are used,
but many patients don’t tolerate it well.”
Unlike the more common obstructive
sleep apnea, in which the airway gets blocked during sleep and causes pauses in
breathing, central sleep apnea is more dangerous
because the brain’s signals to tell the body to breathe get interrupted.
“One of the concerning features of central sleep apnea is that these patients
don’t fit the usual profile of obstructive sleep apnea,” said Dr. Rami Khayat, a sleep medicine
expert and director of Ohio State’s sleep heart program. “They generally don’t
snore, so they’re tougher to diagnose, and the symptoms of sleepiness and
fatigue overlap with symptoms associated with heart failure.”
Abraham and other cardiovascular
researchers at 11centers around the world tested the feasibility, safety and
efficacy of a new transvenous phrenic nerve stimulator made by Respicardia Inc.
The device resembles a pacemaker in that it delivers a regular signal to
stimulate the diaphragm to breathe during sleep.
In the pilot study, 47 patients were
implanted with the device and evaluated for six months. The implant was placed
below the collar bone and a transvenous stimulator lead was positioned near the
phrenic nerve. After a one-month healing period, the device was turned on and
programmed to the patient’s sleep habits.
Researchers saw significant results,
including a 56 percent reduction in overall apnea events per hour and more than
80 percent reduction in central sleep apnea 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,” Abraham
said. “We also noted a reduction in blood pressure in patients with
Now researchers are comparing the
device to current medical therapy for central sleep apnea in a larger
randomized, controlled clinical trial. Ohio State’s Wexner Medical Center is again
the first in the United States to enroll patients in this research. Once study
participants receive the implant, half will have the device turned on soon
after surgery, while the control group will wait six months to have their
device turned on. Up to 25 centers are participating in this larger randomized
trial. Patients will be followed up to five years.
“If these initial findings bear out
in the larger studies, an implantable device could be a good option for central
sleep apnea patients who cannot tolerate positive airway pressure therapy,” Khayat said.
Along with Abraham and Khayat, Ohio
State’s Dr. Ayesha Hasan and Dr. Ralph Augostini are also participating
in this study.
The research is being funded by
Respicardia. Abraham is a consultant for the company.
video and photos of Dr. William Abraham are available for download: bit.ly/18coJqZ
Marti Leitch, Medical Center Public Affairs and Media Relations, 614-293-3737