Sleep apnea treatment good for the heart

By Scott Baltic

NEW YORK (Reuters Health) - The use of a breathing treatment called continuous positive airway pressure, or CPAP, reduced cardiovascular disease risk factors in patients with severe obstructive sleep apnea and metabolic syndrome, but only in those with good adherence to CPAP, Slovakian researchers found.

Obstructive sleep apnea, or OSA, is a common problem, especially among the obese, in which patients stop breathing for short periods during sleep. It occurs when soft tissues in the back of the throat relax and temporarily block the airway. With CPAP, the patient wears a special mask that continuously blows air into the throat, preventing the tissues from collapsing.

The metabolic syndrome is a grouping of risk factors that indicate a high risk of developing cardiovascular disease or diabetes. The risk factors include high triglyceride levels, high glucose (blood sugar) levels, high blood pressure, low levels of "good" HDL cholesterol, and being overweight.

The current study involved 32 patients with both severe CPAP-treated OSA and metabolic syndrome. Sixteen of the study participants had acceptable adherence to CPAP, defined as using the device at least 4 hours per night, and the other 16 did not.

After 8 weeks of CPAP, the adherent group chalked up significant reductions in blood pressure, total blood cholesterol levels and insulin resistance, a precursor to diabetes. In contrast, the nonadherent group showed no significant changes in these measures.

The adherent group also reduced their global risk of cardiovascular disease significantly, whereas the nonadherent group did not.

Similarly, the adherent group experienced significant benefits in terms of harmful oxidative stress and system-wide inflammation, while the nonadherent group did not.

The most common cause of nonadherence to CPAP was leakage from a poorly fitting CPAP mask, study investigator Dr. Ruzena Tkacova of P.J. Safárik University and L. Pasteur Teaching Hospital, Kosice, told Reuters Health. "The leakage was higher in extremely obese patients in our study group, so one could say that morbid obesity likely contributes to the leakage."

SOURCE: Chest, October 2008.