Positive Airway Pressure Therapy can Lower Risk of Heart Attack in Sleep Apnea Patients

by Gopalan on Sep 29 2007 12:04 PM

The heart attack and stroke risks posed by obstructive sleep apnea (OSA) can be countered by administering continuous positive airway pressure, a new study finds.

The study, conducted by Brazilian researchers, is published in the first issue of American Journal of Respiratory and Critical Care Medicine, out in October.

OSA is a condition in which a person's airway is partially or completely blocked during sleep, leading to a lack of oxygen and frequent waking. According to the study, it occurs in nine per cent of middle-aged women and 24 per cent of men. The condition is associated with an increased risk of death from heart disease or stroke.

Majority of patients with OSA share several risk factors for atherosclerosis [the hardening of the arteries leading to heart disease], including obesity, hypertension, hypercholesterolemia, insulin resistance, and hyperglycemia," said T. Douglas Bradley and Dai Yumino, both of the Sleep Research Laboratory at the Toronto Rehabilitation Institute at the Centre for Sleep Medicine and Circadian Biology at the University of Toronto.

In the study, participants' heart health was assessed over four months for indicators of atherosclerosis, arterial plaque levels, arterial stiffness, signs of inflammation, and catecholamine, a marker for physical stress.

After four months of continuous positive airway pressure therapy, which involves the pumping of air through a person's mouth via a mask to keep the airway open, arterial plaque thickness declined by nine percent.

Researchers call the decrease "remarkable" given the fact that in a recent large-scale study, patients undergoing cholesterol-lowering pravastatin therapy saw their arterial plaque thickness decline by twelve percent after a full year.

Arterial stiffness also decreased, by 10.4 per cent.

"Our results demonstrate that four months of effective treatment with continuous positive airway pressure significantly improves validated markers of atherosclerosis in normosensitive middle-aged men with severe OSA," the report states.

The researchers caution that the lower levels of atherosclerosis in patients could be affected by the attitudes of study participants. They say this difference may be due to possible better overall adherence to all prescribed treatments in patients who accept the continuous positive airway pressure therapy than in those who do not, as opposed to any direct benefit that the therapy may offer.