AcuteCare Telemedicine Blog

Obstructive Sleep Apnea and Atherosclerosis

Atherosclerosis is the leading cause of stroke and cardiovascular disease, the leading causes of death internationally, but recently, obstructive sleep apnea (OSA) has also been found to be an independent risk factor for stroke. One explanation may lie in the propensity towards the development of atherosclerosis in this disorder. Identifying this and other potential risk factors of atherosclerosis and understanding how these risk factors behave independently and comorbidly will hopefully reduce the risk of atherosclerotic disease, ultimately aiding in the prevention of stroke.

OSA is a lesser known independent risk factor for stroke than hypertension (HTN), but both are frequently observed as comorbidities in patients with cardiovascular disease and stroke. In 2009, a study published in Hypertension found that patients with OSA and patients with HTN had an increase in carotid wall thickness compared to controls by 19.4% and 19.5% respectively. In patients with OSA and HTN, the increase was found to be 40.3% in carotid wall thickness over controls. These and other findings strongly suggest that OSA is indeed an independent risk factor for the development of carotid atherosclerosis.

OSA has been shown to independently increase several markers of atherosclerosis including sympathetic activity, pro inflammatory factors and endothelial dysfunction. In addition, OSA can lead to other atherosclerotic risk factors such as alteration in lipid metabolism, insulin resistance and hypertension.  In 2007, a separate study published in the American Journal of Respiratory and Critical Care Medicine involved twenty-four patients with OSA and without comorbidities. After 4 months of treatment with continuous positive airway pressure, there was a reduction in markers of inflammation and sympathetic activation as well as a decrease of carotid wall thickness; again evidence to suggest OSA as a risk factor for atherosclerosis.

The importance of these studies and others suggesting OSA as an independent risk factor for atherosclerosis is to arm physicians with more ways to combat the incidence of stroke and cardiovascular disease. Because of the high incidence of OSA in patients with HTN, control of HTN alone may not adequately reduce atherosclerotic risk. Screening tools such as the STOP/BANG and Berlin questionnaire should be utilized in  hypertensive patients, particularly those with refractory disease (>3 BP meds with adequate control or 3 BP meds with inadequate control). Overnight polysomnography should be performed in patients identified at risk for OSA and treatment should be initiated when appropriate. Likewise, in patients without known atherosclerotic risk factors but suspected OSA, screening and diagnostic studies should be performed. These measures can help to further reduce the incidence of atherosclerosis and subsequently reduce the incidence of cardiovascular disease and stroke.

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