CPAP Reverses Atherosclerotic Effects of Sleep Apnea
April 28th, 2007 Posted by: Dr. Cox
SAO PAULO, Brazil, Sept. 28 — Treatment of obstructive sleep apnea with continuous positive airway pressure reverses early signs of atherosclerosis, researchers here found.Action Points
Explain to interested patients that the study affirms a causal link between obstructive sleep apnea and atherosclerosis.
Inform patients that CPAP may help reverse the cardiovascular risk caused by severe sleep apnea, but further study is needed to show it prevents heart attack and other outcomes.
In a carefully controlled, randomized trial, CPAP therapy reduced carotid intima-media thickness 9% over four months and improved arterial stiffness 10% among men with severe sleep apnea reported in the first October issue of the American Journal of Respiratory and Critical Care Medicine.
These were “remarkable” changes as great as improvements seen in statin trials over six months to a year, said Luciano F. Drager, M.D., of the University of São Paulo here, and colleagues.
Furthermore, the findings provide the first solid evidence of the long-suspected causal link between sleep apnea atherosclerosis, commented T. Douglas Bradley, M.D., and Dai Yumino, M.D., both of the Center for Sleep Medicine and Circadian Biology at the University of Toronto, Canada, in an accompanying editorial.
“Because obstructive sleep apnea affects approximately 10% of the adult population,” they wrote, “these results may have important public Men’s health implications for prevention of atherosclerotic diseases.”
The link has been difficult to prove because the majority of sleep apnea patients have other risk factors for atherosclerosis, including obesity, hypertension, high cholesterol levels, insulin resistance, and hyperglycemia, they said.
Of the 400 consecutive men who had more than 30 apnea and hypopnea events per hour during a polysomnographic sleep test at the Brazilian center, the researchers excluded all but 24 for atherosclerosis risk factors.
The study included only treatment-naïve men 60 or younger with a body mass index no greater than 35 kg/m2 and no diabetes, hypertension, cerebrovascular or heart disease, renal failure, smoking history, or chronic use of any medication.
These participants were randomly assigned to CPAP or no treatment for four months.
On CPAP therapy, the average apnea-hypopnea index dropped to 4.5 events per hour and early vascular markers of atherosclerosis fell as well.
Carotid intima-media thickness improved significantly from baseline to four months in the CPAP group (707 versus 645 µm, P=0.04) whereas it got slightly worse in the control group (732 versus 740 µm). The overall difference between the groups was significant (P=0.02).
Arterial stiffness as measured by carotid-to-femoral artery pulse-wave velocity was unchanged in the control group (10.1 versus 10.3 m/s) but decreased significantly in all CPAP-treated patients (mean 10.4 versus 9.3 m/s, P