In my previous post, I talked about Obstructive Sleep Apnea (OSA) as a contributing factor or cause of ischemic stroke. It is important to emphasize, however, that not only can OSA increase the risk for stroke, but prior research also has shown that any patient who has had a stroke has a much higher risk of either developing or exacerbating OSA as a consequence of a stroke. Neurological deficits following a stroke often include weakness of the face, tongue, or muscles of respiration.

As a result, OSA can be a major problem for post-stroke patients as a cause of

• excessive fatigue or sleepiness
• decreased cognitive function
• a potential risk for having more future strokes

What does this mean for health care professionals? There is a strong two-way relationship between OSA and stroke, and prevention is key. Most of us in the medical community are now aware of the close relationship between sleep apnea and cardiovascular diseases. OSA is now recognized as the number one known cause of high blood pressure in the United States and is associated with a 3-fold increased risk of heart attack.

More health professionals now need to recognize OSA as a potential trigger for ischemic stroke and to have a high index of suspicion for underlying OSA in patients who have had a stroke, particularly if they have lasting neuromuscular weakness. Health care professionals need to have a strong awareness of this two-way relationship between OSA and stroke, and should integrate OSA screening and evaluation in their clinical practice as part of any cardiovascular disease prevention or management program.

Most health care professionals are aware of the cardiovascular consequences of sleep apnea. Less known are the serious consequences of sleep apnea on ischemic stroke. A new study shows that Obstructive Sleep Apnea (OSA) can significantly increase the risk for stroke as well. According to the study, the incidence rate of having an ischemic stroke nearly triples in men 40 and older with moderate to severe untreated OSA. OSA-related stressors are suspected to alter cerebral tissue oxygenation, blood flow and/or vascular autoregulation, and consequently, contribute to stroke risk.

The data, collected over an eight-year span on a large, geographically diverse population, was part of a longitudinal cohort study of 5422 patients in the Sleep Heart Health Study. The results were recently published in the American Journal of Respiratory and Critical Care Medicine, and revealed that men with an apnea + hypopnea index (AHI) of 20 or greater breathing stoppages per hour of sleep had almost three times the risk of developing a future stroke. Indeed, the incidence of ischemic stroke for men increased 6% with every unit increase in baseline AHI from 5 to 25. Surprisingly, increased risk of stroke in women was observed only when the AHI was 25 or more. Unlike men, stroke risk in women was significantly associated with diabetes, hypertension medication use and smoking. Potential explanations for the discrepancy between genders may be attributed to the different influence sex hormones may play on vascular function.

If you are a health care professional, screening your patients with a brief sleep history or incorporating sleep questionnaires in your practice to identify patients at risk for OSA can have significant health benefits, particularly for those at higher risk for cardiovascular events such as stroke or myocardial infarction. Prevention, as always, is the best course of action, and data have consistently shown that treating OSA can significantly improve a patient’s cardiovascular risk profile.