According to a new study conducted by Brazilian researchers, early signs of atherosclerosis in obstructive sleep apnea can successfully be treated with a new treatment known as continuous positive airway pressure (CPAP).
The study has been published the October issue of the prestigious medical journal American Journal of Respiratory and Critical Care Medicine.
Luciano F. Drager, M.D., of the University of São Paulo, and colleagues conducted a carefully controlled trial over four months. The trial showed that CPAP therapy reduced carotid intima-media thickness by 9% and improved arterial stiffness by 10% among men with severe sleep apnea. Both, carotid intima-media thickness and arterial stiffness are indicators of atherosclerosis.
The trial started examining about 400 people who has 30 apnea and hypopnea events per hour during sleep tests at the Hypertension Unit and Sleep Laboratory, Pulmonary Division, Heart Institute, University of São Paulo Medical School, São Paulo, Brazil).
From these patients, only 24 were selected because they did not exhibit other atherosclerosis risk factors. The study included men under 60 years with a body mass index lower than 35 kg/m2 and with no diabetes, hypertension, cerebrovascular, heart disease, renal failure, or smoking history.
Participants were assigned randomly to two groups CPAP treatment and no treatment. They were carefully monitored during a four months period. Carotid intima-media thickness, arterial stiffness, carotid diameter, 24-hour blood pressure monitoring, C-reactive protein, and catecholamines were determined at start and after 4 months.
Results showed that the CPAP group dropped the average apnea-hypopnea index 4.5 events per hour. Early vascular markers of atherosclerosis also decreased significantly.
More specifically the study found:
*Carotid intima-media thickness improved significantly from baseline to four months in the CPAP group (707 versus 645 µm)
*Arterial stiffness 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)
*The inflammatory marker C-reactive protein likewise improved only in the CPAP group
*The activation marker catecholamine showed the same pattern of improvement in the CPAP group (365 versus 205) but not the control group (362 versus 357)
All these results showed that the treatment of Obstructive Sleep Apnea with continuous positive airway pressure significantly improves early signs of atherosclerosis.
Obstructive sleep apnea is a sleep disorder characterized by pauses in breathing during sleep. These “without – breath – episodes”, called apneas, last long enough so one or more breaths are missed. An overnight sleep test, known as polysomnogram, is the only way to truthfully diagnose sleep apnea. It is estimated that 20% of Americans suffer from obstructive sleep apnea (Shamsuzzaman et al 2003).
Hypertension and stroke are often associated with obstructive sleep apnea. Also, sleep apnea sufferers have a 30% higher risk of death, according to the American Thoracic Society.
Drager LF, et al “Effects of Continuous Positive Airway Pressure on Early Signs of Atherosclerosis in Obstructive Sleep Apnea” Am J Respir Crit Care Med 2007; 176: 706-712.
Shamsuzzaman AS, Gersh BJ, Somers VK (October 2003). “Obstructive sleep apnea: implications for cardiac and vascular disease”. Journal of the American Medical Association 290 (14): 1906-14.
N.A. Shah, M.D., N.A. Botros, M.D., H.K. Yaggi, M.D., M., V. Mohsenin, M.D., New Haven, CT (May 20, 2007). Sleep Apnea Increases Risk of Heart Attack or Death by 30%. American Thoracic Society.