Is sleep apnea a risk factor for stroke? A critical analysis.

Stroke is the 3rd leading cause of death and a major cause of serious long-term disability in the United States. There are several well established and modifiable risk factors for the development of stroke. These include arterial hypertension, cardiac disease, dyslipidemia, diabetes mellitus and smoking among others. Sleep apnea has been found at alarmingly high rates (>50%) in patients with acute stroke as well as after neurologic recovery leading some to speculate that sleep apnea had been present prior to stroke. Sleep apnea is highly prevalent in the general population with a frequency of 2% to 4%. Sleep apnea is associated with high incidence of obesity, coronary artery disease and hypertension. There are several hematologic and hemodynamic changes in sleep apnea that can play significant roles in the pathogenesis of stroke. In this review, the author provides a critical analysis of the association between sleep apnea and stroke. There is convincing evidence to believe that sleep apnea is a modifiable risk factor for stroke, however, prospective studies are needed to establish the cause-and-effect relationship. Stroke and sleep-related breathing disorders are both common and are associated with significant morbidity and mortality. Several recent large epidemiological studies have shown a strong association between these 2 disorders independent of known risk factors for stroke. Understanding the link between obstructive sleep apnea and stroke may provide a novel preventative and therapeutic approach in the management of stroke.