Cardiovascular Complications of Sleep-Related Breathing Disorders

Obstructive sleep apnea is associated with an increased risk of cardiovascular disease and stroke.Three pathophysiological mechanisms characterize sleep-related breathing disorders: (1) upper airway instability; (2) respiratory control instability, and (3) respiratory pump disorders. Especially the intrathoracic pressure swings during obstructed breathing, hypoxemia as a result from apneic events, and arousals from sleep (terminating the apneas) are responsible for the cardiovascular consequences. Obstructive sleep apnea is an independent risk factor for systemic hypertension and has also been implicated in the pathogenesis of pulmonary hypertension, arrhythmias, atherosclerosis, coronary artery disease and myocardial infarction, stroke, and congestive heart failure. Treatment of obstructive sleep apnea - especially with CPAP - improves breathing and eliminates the acute hemodynamic effects during sleep. In addition, long-term treatment with CPAP has a beneficial influence on the cardiovascular consequences: left ventricular function, systemic and daytime pulmonary hypertension improve, and there is also evidence that the otherwise increased cardiovascular morbidity and mortality can be normalized.