Getting to the Heart of Sleep Apnea

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Obstructive sleep apnea linked to risk factor related to heart damage

October 24, 2013 / Author:  / Reviewed by: Chris Galloway, M.D. Beth Bolt, RPh

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(dailyRx News) A sleeping disorder such as obstructive sleep apnea can have an impact on much more than your sleeping patterns. It can also affect your risk for other conditions.

A recent study found that obstructive sleep apnea was linked to a risk factor related to heart damage and heart failure.

The study results did not establish that obstructive sleep apnea caused damage to the heart. However, the results did suggest a link between the sleeping disorder and the risk for heart failure seen in past studies.

The researchers said that more research needs to be done to understand how obstructive sleep apnea and heart conditions are related.

"Get treatment for your sleep apnea."

This study, led by Gabriela Querejeta Roca, MD, of the Division of Cardiovascular Medicine at Brigham and Women’s Hospital in Boston, looked at whether sleep apnea patients were more likely to have stress or injury on their hearts.

The researchers studied 1,645 participants who were an average age of 63 and did not have any symptoms of heart disease or heart failure.

All the participants underwent sleep studies to determine if they had obstructive sleep apnea and, if so, how severe it was.

The severity of obstructive sleep apnea was determined by the apnea-hypopnea index (AHI), also called the respiratory disturbance index (RDI).

The AHI or RDI score a person receives represents the number of times they stop breathing for at least 10 seconds or have a certain amount of decrease in air flow or blood oxygen saturation during one hour of sleep.

An AHI score below 5 means the person does not have sleep apnea. A score of 5 to 15 means the adult has mild obstructive sleep apnea, while a score of 15 to 30 is moderate and more than 30 is severe.

The researchers also conducted two other tests with the participants: high sensitivity troponin and N-terminal pro B-type natriuretic peptide.

Each of these lab tests are used by medical professionals to help diagnose cardiac risk in patients without current symptoms, as well as cardiac damage when used in an acute setting such as an ER.

The researchers found that participants with obstructive sleep apnea were more likely to have higher amounts of the troponin, indicating coronary disease risk, than the patients without sleep apnea.

These results held true even after the researchers took into account other factors that might influence the participants' levels of troponin.

However, the levels of the natriuretic peptide did not appear to be different between those with or without obstructive sleep apnea.

The researchers tracked the participants for a typical time period of about 12 years.

During this time, the participants whose tests showed elevated levels of troponin were more likely to die or experience heart failure than the patients who did not have those results.

The researchers concluded that older individuals with obstructive sleep apnea were therefore more likely to have higher levels of the troponin, which also appeared to suggest they were more likely to have damage in their hearts.

However, the study results do not mean that having obstructive sleep apnea caused heart damage, heart failure or an increased amount of troponin.

William Kohler, MD,  the medical director of the Florida Sleep Institute in Spring Hill, Florida, agrees with the authors that more research is needed to understand the relationship between obstructive sleep apnea and possible damage to the heart.

"This study offers additional information about the an association between obstructive sleep apnea and heart disease," Dr. Kohler said.

"Further research is necessary to show the exact involvement of obstructive sleep apnea in contributing to heart disease," he said. "We know there's an association but the degree of the contributing or causal factor for heart disease is still yet to be confirmed."

The standard treatment for obstructive sleep apnea is continuous positive airway pressure, or CPAP.

CPAP involves wearing a mask while a person is asleep. The CPAP machine and mask pump air into the person's air passageways.

CPAP machines require a prescription and can cost anywhere from $150 to over $5,500, though most insurance plans will cover some or all of the expense. CPAP masks range from $30 to $200.

This study was published October 25 in the American Journal of Respiratory and Critical Care Medicine. Information on conflicts of interest was unavailable.

The research was funded by the National Heart, Lung and Blood Institute, Brigham and Women's Hospital, the University of Washington and the University of Minnesota.