Heart Failure Patients Benefit from Implant Device for Central Sleep Apnea
Principal Investigator William Abraham, MD, Leads Study from Ohio State
For Americans with central sleep apnea, including 2.4 million with heart failure, a new implant device is showing positive results. The implanted transvenous phrenic nerve stimulator delivers a regular signal to stimulate the diaphragm to breathe during sleep. Principal Investigator William Abraham, MD, director of the Division of Cardiovascular Medicine at The Ohio State University Wexner Medical Center, led a pilot study with cardiovascular researchers at 11 centers around the world to test the feasibility, safety and efficacy of the pacemaker-like device made by Respicardia, Inc.
Significant Pilot Study Results
During the pilot study of 47 patients, researchers saw a 56 percent reduction in overall apnea events per hour and more than 80 percent reduction in central sleep apnea events. The first U.S. patient to receive the device and participate in the study came to The Ohio State University's Richard M. Ross Heart Hospital. Dr. Abraham presented the findings at the Heart Failure Society of America's Annual Scientific Meeting in fall 2013.
"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 says. "We also noted a reduction in blood pressure in patients with hypertension."
Researchers implanted the device in study participants and evaluated them for six months. The device is implanted under the skin below the collarbone, and a transvenous stimulator lead is positioned near the phrenic nerve. After a one-month healing period, the device is turned on and programmed to the patient's sleeping habits.
Similar to a pacemaker, the small, sealed device delivers small electrical pulses. Leads deliver pulses and information back to the device. Physicians monitor the information and can noninvasively change the device settings. Batteries in the implant last from three to seven years.
Link to Heart Failure
"Central sleep apnea affects more than a third of heart failure patients and is known to make the condition worse," Dr. Abraham says. "Unfortunately, we don't have good treatments available for this type of apnea. It is generally treated with continuous positive airway pressure, or CPAP, which can be difficult for some patients to tolerate."
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.
Larger Study: Potential for Widespread Use
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 participants will wait six months to have their devices 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.
"Literally millions of patients may be eligible for treatment with this device," Dr. Abraham says. "Once implanted, it's automatic. It requires no patient intervention and no patient compliance. There is very little discomfort associated with the implant procedure and no discomfort once implanted."
Along with Dr. Abraham, Ohio State's Rami Khayat, MD, Ayesha Hasan, MD, and Ralph Augostini, MD, also are participating in this study.
The research is being funded by Respicardia. Dr. Abraham is a consultant for the company.