A device implanted under the skin like a pacemaker successfully treats central sleep apnea (CSA) in heart failure patients, according to research presented this month at the Heart Failure Congress 2014, held May 17 to 20 in Athens, Greece. The Congress is the main annual meeting of the Heart Failure Association of the European Society of Cardiology.
The 1-year results of the Remede system pilot study were revealed for the first time by lead author Professor William T. Abraham from Ohio State University.
Central sleep apnea (CSA) is a comorbidity in approximately 35% of heart failure patients and doubles the risk of death. The Remede system uses unilateral transvenous phrenic nerve stimulation to prevent CSA before it occurs. The pulse generator is implanted under the skin like a pacemaker, just below the collar bone, and a wire is threaded into one of the veins near the phrenic nerve.
Professor Abraham says in a release: “The device stimulates the diaphragm via the phrenic nerve, causing the diaphragm to contract. It regularizes the patient’s breathing pattern throughout the night, rather than waiting until the patient stops breathing to react.”
The Remede system pilot study was a prospective, multicenter trial in 46 patients with moderate to severe CSA who were implanted with the Remede system. The primary endpoint was a reduction in apnea hypopnea index (AHI) at 3 months compared to baseline with 6 and 12 month data also collected.
The 1-year results show that the Remede system led to substantial benefits in sleep parameters including a reduction in AHI, a reduction in the time spent with low blood oxygen levels overnight, and improvements in sleep efficiency and REM sleep.
The Remede system also improved important cardiac endpoints such as heart rate variability, which is a measure of autonomic balance. Patients were less sleepy and their quality of life improved, according to the Minnesota Living with Heart Failure Quality of Life questionnaire.
Professor Abraham says: “Patients with the Remede system feel better, they are less symptomatic, their quality of life is improved, and the underlying mechanisms that lead to heart failure progression such as autonomic imbalance are improved.”
Favorable effects on the structure and function of the heart, called reversed remodeling, were also demonstrated. In patients with the implantable device, the heart got smaller, the left ventricular diastolic volume decreased significantly, and the heart became stronger, with significant improvements in left ventricular ejection fraction. Professor Abraham says: “These are changes that generally correlate with improvement in long term clinical outcomes.”
Professor Abraham concludes: “All heart failure patients should be screened for sleep apnea and those with OSA should be offered a mask-based therapy. Patients with CSA are good candidates for the Remede system which can improve their sleepiness, quality of life, and potentially their clinical outcomes.”
The pivotal trial for US regulatory approval is ongoing and is set to enroll around 150 patients in the United States and Europe. Results are expected by the end of 2015.