Sleep-disordered breathing and the association with cardiovascular risk

Breathing-related sleep disorders, particularly obstructive sleep apnea, have been largely undiagnosed in people with cardiovascular disease, probably due to limited health care provider awareness of the association between the two conditions. Solid evidence is emerging that the apneic events that occur during sleep lead to acute and chronic hemodynamic changes during wake time, including elevated sympathetic tone, decreased stroke volume and cardiac output, increased heart rate, and changes in circulating hormones that regulate blood pressure, fluid volume, vasoconstriction, and vasodilation. Obstructive sleep apnea is associated with known cardiovascular risk factors such as obesity and hyperlipidemia, and is considered by many sleep clinicians to be an independent risk factor for hypertension. Additionally, sleep apnea has been implicated in the pathogenesis of heart failure and stroke. Treatment with positive airway pressure during sleep eliminates the apneic events and the ensuing acute hemodynamic changes. Improvements in daytime blood pressure and left ventricular function also have been noted in persons with hypertension and heart failure. Because effective treatment is available for sleep apnea, this condition needs to be diagnosed and treated in persons with cardiovascular disease.