Treating obstructive sleep apnea, preventing heart attacks and strokes
Breathing and life so interlinked
Stop for a moment and we hurt
Stop on a regular time and subtle
Damage... Perhaps.
Bill
Never heard of continuous positive airway pressure.
..................
Public release date: 28-Sep-2007
Contact: Keely Savoie
212-315-8620
American Thoracic Society
Treating obstructive sleep apnea, preventing heart attacks and strokes
Researchers in Brazil have found that treating patients who suffer from
obstructive sleep apnea (OSA) with continuous positive airway pressure
(CPAP) dramatically reduces early indications of atherosclerosis in just
months, linking OSA directly to the hardening or narrowing of the
arteries. Until now, no study has demonstrated such a direct
relationship between the two.
3OSA is independently associated with increased risk of fatal
cardiovascular events that can be reversed by treatment with CPAP,2
wrote Luciano Drager, M.D., of the University of S?o Paulo Medical
School in Brazil.
The research was published in the first issue of the American Journal of
Respiratory and Critical Care Medicine for October of 2007, published by
the American Thoracic Society.
The researchers selected 24 men with severe OSA and no other
comorbidities and randomly assigned them to receive either CPAP therapy
or no treatment. After establishing the baseline data for each subject,
they then tracked several indicators of pre-clinical atherosclerosis,
including carotid intima-media thickness (a measure of arterial plaque),
pulse-wave velocity (a measure of arterial stiffness), carotid diameter,
C-reactive protein (a marker of inflammation), and catecholamine level
(a marker of physical stress) over the course of four months.
3[All markers] were similar across the study period in the control
group,2 wrote Dr. Drager. 3In contrast, the group treated with CPAP had
a significant decrease in carotid intima-media thickness, pulse-wave
velocity, C-reactive protein, and catecholamines.2
While there is a known association between OSA and risk of myocardial
infarctions and strokes, the causal connection between OSA and
atherosclerosis as the principle mechanism behind those cardiovascular
events has proven difficult to establish.
3The majority of patients with OSA share several risk factors for
atherosclerosis, including obesity, hypertension, hypercholesterolemia,
insulin resistance, and hyperglycemia,2 explained T. Douglas Bradley,
M.D., and Dai Yumino, M.D., 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 an editorial in the
same issue of the journal.
Furthermore, while non-randomized observational trials have suggested
that the risk of adverse cardiovascular events is lower among patients
who accept treatment by CPAP than in patients who do not accept CPAP
therapy, it is possible that this difference may be due to better
overall adherence to all prescribed treatments in patients who accept
CPAP than in those who do not, as opposed to any direct benefit of CPAP
itself.
3Whereas physiological studies suggest that OSA provides a substrate for
the development of atherosclerosis, and epidemiological and
observational studies suggest an association between OSA and odds of
having atherosclerosis, there remains a gap between cause and effect yet
to be filled,2 wrote Drs. Yumino and Bradley. 3Drager and colleagues
provide evidence that begins to fill that gap.2
Indeed, after four months of CPAP therapy, carotid intima-media
thickness declined by nine percent, which is remarkable in light of the
fact that in a large-scale study, patients undergoing
cholesterol-lowering pravastatin therapy saw carotid intima-media
thickness decline by twelve percent after a full year. Other indicators
showed similar magnitudes of improvement.
The researchers put forth a number of potential pathways whereby OSA
could contribute to atherosclerosis progression, including inflammation,
oxidative stress, lymphocyte activation, and high-density lipoprotein
dysfunction. 3CPAP treatment could reverse several of these pathways,2
they wrote.
Still, the investigators caution that, while they are confident in the
biological validity of their results, the rigid inclusion criteria makes
it difficult to extrapolate their results to different populations,
including women, patients with other co-morbidities and patients with
mild to moderate OSA.
--
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This article is posted under fair use rules in accordance with
Title 17 U.S.C. Section 107, and is strictly for the educational
and informative purposes. This material is distributed without profit.
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