Obstructive sleep apnea and cardiovascular diseases

Abstract

Obstructive sleep apnea (OSA) and its cardiovascular consequences have attracted considerable attention in recent years. The strong association between OSA and cardiovascular disease (CVD) is well documented. OSA may have a pathogenic role in CVD; it may pose an acute adverse physiologic milieu in pre-existent CVD, or it may merely share common etiologic factors, such as obesity, with CVD. These relationships are not mutually exclusive, and there is compelling evidence that all three components may exist. Many pathophysiologic events in OSA can affect the cardiovascular system, notably acute recurrent hypoxia, intrathoracic pressure swings, and sympathetic discharge. A causal role of OSA in hypertension (HT) is consistently supported by several recently published community-based studies. Epidemiologic studies and clinical series also suggest adverse effects of OSA on left ventricular function and ischemic heart disease. With the currently available evidence, routine laboratory screening for OSA in all patients with cardiovascular disorder is not justified, but clinicians are encouraged to take detailed sleep histories in such patients and refer them for definitive sleep studies if OSA is suspected. The threshold for treatment of OSA in the light of potential cardiovascular morbidity is not universally agreed upon, and there are different schools of thought regarding criteria for treatment in those without significant symptoms directly attributed to OSA. However, common wisdom would suggest that the severity of sleep disordered breathing and the severity of any pre-existing cardiovascular disease will be the determinants for management in individual cases.