Treating sleep apnea good for the heart

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Treatment of the nighttime breathing disorder, obstructive sleep apnea, with continuous positive airway pressure (CPAP) seems to have a beneficial impact on early signs of atherosclerosis (hardening of the arteries), Brazilian researchers report.

Obstructive sleep apnea (OSA) occurs when the soft tissues at the back of the throat repeatedly collapse during sleep, temporarily cutting off breathing. It has been linked to heart attack and stroke, and both associations appear to be fueled through effects on atherosclerosis. Whether effective treatment of OSA would reduce the plaque burden, however, was unclear.

Dr. Luciano F. Drager and colleagues from University of Sao Paulo Medical School assessed changes in the thickness of the neck artery and other parameters among 24 patients with severe OSA randomized to receive CPAP or no treatment for 4 months. Considered the most effective therapy for OSA, CPAP involves wearing a face mask through which the CPAP device delivers pressurized air to keep the airways open.

The control group experienced no changes in any of the parameters measured during follow-up. In the CPAP group, by contrast, the investigators documented reductions in the thickness of neck arteries and in the stiffness of the arteries.

The CPAP group also experienced healthy reductions in CRP -- a marker of inflammation associated with an increased risk of cardiovascular disease -- and catecholamines -- compounds that constrict blood vessels, increase heart rate and boost blood pressure.

"The magnitude of improvement on validated markers of atherosclerosis after CPAP is in some aspects comparable to that observed for statins used in patients with dyslipidemia," Drager told Reuters Health. "However, in opposite to the main effect of statins promoting significant lipid-lowering effects, we did not observe any significant reductions in lipids but in markers of inflammation and sympathetic activation."

Drager cautioned that further studies are needed to determine if CPAP slows the progression of atherosclerosis in OSA patients.

SOURCE: American Journal of Respiratory and Critical Care Medicine, October 2007.