Implantable device treats heart failure patients with central sleep apnea
According to research presented at the annual meeting of the Heart Failure Association of the European Society of Cardiology in Athens, Greece, heart failure patients who suffer from central sleep apnea - a condition in which the brain fails to control breathing properly during sleep - have successfully been treated with a new device that is implanted under the skin.
Prof. William T. Abraham, from Ohio State University, presented the 1-year results of a pilot study for the Remede system, which he explains as "the first fully implantable device to treat central sleep apnea in heart failure patients."
He and his team explain that central sleep apnea (CSA) is a comorbidity in around 35% of heart failure patients, doubling their risk of death.
People with sleep apnea typically make gasping or snorting noises, momentarily disrupting their sleep. Because their sleep is regularly interrupted, such individuals may also encounter daytime sleepiness.
More than just a nuisance, sleep apnea can cause serious health complications, including hypertension, heart disease, and mood and memory problems. In the US, more than 18 million adults have some form of sleep apnea.
Traditional therapies for the condition include wearing a mask, known as a continuous positive airway pressure (CPAP) mask, which supplies a constant flow of air through the nose. But this only works on some CSA patients under certain conditions, says Prof. Abraham.
However, patients using the new implantable device "tell us they haven't slept so well in years," he says. "They have more energy and can do their normal daily activities without falling asleep. They also don't have to fight with a mask."
Device prompted improvements in heart structure, function
Using a unilateral transvenous phrenic nerve stimulation, the device prevents CSA before it occurs, says the team.
Much like a pacemaker, the pulse generator is implanted just below the collar bone and under the skin. Then, a wire is threaded into a vein near the phrenic nerve.
The device, which is implantable under the skin, led to significant improvements in sleep and is not as inconvenient as CPAP masks.
Prof. Abraham explains that the device "stimulates the diaphragm via the phrenic nerve, causing the diaphragm to contract," and it regulates breathing patterns during the night, rather than reacting when the patient stops breathing.
In a prospective, multicenter trial, 46 patients with moderate to severe CSA were implanted with the device.
After 1 year, results show that the device led to significant improvements in sleep, including a reduction in the apnea-hypopnea index, a reduction in time spent with low blood oxygen levels at night, and improvements in REM sleep and sleep efficiency.
The researchers also observed that the patients had improved heart rate variability and they were less sleepy, prompting an overall quality-of-life improvement, according to the Minnesota Living with Heart Failure Quality of Life questionnaire.
Additionally, the team observed reverse remodelling, which means there were "favorable effects" on heart structure and function. In detail, in patients with the device, the heart got smaller, the left ventricular diastolic volume decreased, and the heart became stronger.
Prof. Abraham notes that mask therapies are problematic because nearly half of patients cannot or will not wear the mask, "so their sleep apnea is untreated or inadequately treated."
"All heart failure patients should be screened for sleep apnea and those with [obstructive sleep apnea] 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 researchers say their trial is ongoing for US regulatory approval, and results will likely be in by the end of 2015.
Medical News Today recently reported on a study that suggested pneumonia risk is higher in people with sleep apnea.
Written by Marie Ellis
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