Photo of bedding and pillowsMedical professionals are being urged to stop using adaptive servo-ventilation therapy in heart failure patients with central sleep apnea because of a new study that found the treatment increases mortality rates.

“We’re looking at sudden death in these patients,” said the author of the study, Dr. Martin Cowie of Imperial College London, during a news conference where he presented the results at this month’s European Society of Cardiology meeting.

The study also was released in The New England Journal of Medicine.

Adaptive servo-ventilation, or ASV, is a treatment that forcefully delivers air through a face mask worn by patients while sleeping. The device is often used by heart failure patients with central sleep apnea, a neurological problem in which the brain fails to signal the respiratory system to continue breathing during sleep.

The new study looked predominantly at patients with central sleep apnea, which is less common than obstructive sleep apnea, a physical problem in which an individual’s airway is blocked by the muscles or tissues of a person’s mouth or throat.

ASV had generally been believed to be the correct treatment for patients using it, said Dr. Mariell Jessup, a University of Pennsylvania cardiologist and medical professor.

“This is totally unexpected, and very disturbing,” she said about the study’s results. “Furthermore, they don’t really have a good idea of the mechanisms.”

The study examined 1,325 patients who had a reduced ventricular ejection fraction of 45 percent or less. Ejection fraction is the form of measurement used to determine how much blood is being pumped by the heart.

Individuals using ASV therapy, specifically heart failure patients with reduced ejection fraction, should stop using the treatment until they can speak with both their sleep specialist and their cardiologist to determine whether the study pertains to them, Jessup said.

The study raises questions about the best potential alternatives to ASV as well as whether central sleep apnea needs to be treated at all.

“This is really a surprising finding because we thought we were going in the right direction with this type of therapy,” said Dr. Mary Norine Walsh, medical director of the Heart Failure and Cardiac Transplantation Programs at St. Vincent Heart Center in Indianapolis.

Walsh also expressed concern that 90 percent of the study’s trial were men, which she said makes it difficult to apply the findings to women.

“When a study is done that way, it’s hard to tease out sex-specific effects,” she said. “So when a study like this is predominantly performed with men, it can’t be definitive in all patients. It doesn’t mean that the findings are false, it’s just that we ask, ‘Should we assume the same results in women’?”

But Jessup said men are generally more likely to have sleep apnea. They also are more likely to have low ejection fraction.

“I think that’s just the patients who get this disease,” she said.