[Sleep apnea syndrome (SAS) and ischemic heart disease (IHD)]

Several epidemiological studies have suggested that sleep-disordered breathing is a risk factor for cardiovascular disease, particularly hypertension, stroke and IHD. The relative risk for IHD among obstructive SAS(OSAS) patients is 1.2 to 6.9 higher compared with the general population. The prevalence of SAS with an apnea-hypopnea index(AHI) of 10 and over was 35 to 40% in IHD, while 23.8% of SAS patients had IHD. These evidence suggests that IHD is an important prognostic factor in SAS patients. Characteristic pathophysiological conditions such as sleep apnea-induced hypoxemia and sympathetic activation may play an important role in the genesis of nocturnal angina pectoris. Most patients with OSAS are obese, and the complication of non-insulin dependent diabetes mellitus is quite a few. Insulin resistance is also attracting great attention as a cause of the cardiovascular complication of SAS.