| 1. BackgroundMore and more evidences indicate a strong association between sleep-disordered breathing(SDB) and cardiovascular disease(CVD) along with abroad study for SDB in the world. SDB is hypothesized to increase the risk of developing CVD and is a independent risk factor of CVD. Retrospective studies suggest that crude mortality is increased in untreated patients with SDB, which may be due to coexisting cardiovascular morbidity. So SDB is regarded as an important influential factor of mortality. Cross-sectional results of the Sleep Heart Health Study (SHHS, supported by NIH ) indicated that SDB within a range of RDI (respiratory disturbance index) values that is considered only mildly elevated has a modest to moderate effects on various manifestations of CVD.Up to now there are no large community-based epidemiologic studies for SDB in China. There are no studies about relation of SDB to coronary artery disease (CAD) and its possible mechanism yet. Although the clinical features of SDB are well characterized, many aspects of its pathogenesis and pathophysiology remains to be defined. Progress in understanding SDB has been hampered by the lack of a suitable animal model of the disorder.This paper expect to provide new idea of effective treatment to CAD by studying the relation of SDB to CAD and its possible mechanism from clinic and experiment aspect, so as to decrease the morbidity and mortality of CVD.2. ObjectivesTo explore the relations between SDB and CAD from clinic and experiment aspect. The aim of clinical research was to understand whether SDB was independent risk factor of CAD which verified by angiographically and to examine the occurrence of nocturnal myocardial ischemia and its relationship to SDB. The aim of experiment study was to build up obstructive sleep apnea syndrome (OSA) animal models and OSA combine CAD animal models, to observe whether OSA can result in coronary atherosclerosis and accelerate the expansion of atherosclerosis, accordingly putting organism with CAD at a greater risk.3. Methods and results3.1 Relations between sleep-disordered breathing and coronary artery diseaseMethods: 128 patients were referred for evaluation of CAD by coronary angiography because of angina pectoris. CAD was diagnosed by a stenotic lesion of at least 50% in one or more coronary arteries. Patients with stenotic lesions less than 50% were classified as control subjects. The risk factors and concomitant diseases were recorded by questionnaire investigate and medical record. Overnight sleep studies were performed in all patients. Cessation of airflow for at least 10 seconds with a fall in oxygen saturation > 4% was classified as apnea. Reduced airflow of at least 50% associated with a fall in oxygen saturation > 4% was classified as hypopnea. According to international standard, patients were classified as having SDB with a RDI > 5 and ODI > 5. A logistic regression analysis was performed to assess associations between risk factors and CAD.Results: SDB was found far more frequently in CAD patients than in10control subjects(46.9% vs 21.8%, p<0.05). The mean RDI was significantly higher (p<0.05) in CAD patients than in control subjects. Multiple logistic regression analysis revealed SDB (OR2.4; CI 1.5-5.1; p<0.05) and hyperlipidemia (OR 4.4; CI 2.3-7.9; p<0.01) were independently associated with CAD. SDB defined as RDI > 20(OR2.1; CI 1.1-3.7; p<0.05) and hyperlipidemia (OR 2.3; CI 1.2-3.8; p<0.01) were both independently associated with myocardial infarction.3.2 The effect of Sleep-Disordered Breathing on Myocardial Ischemia in Patients With Coronary Artery DiseaseMethods: 52 patients referred for coronary angiography because of angina pectoris were randomly selected. All subjects completed the questionnaire. SDB was measured as RDI and ODI, calculated as the average number of episodes of desaturation and apnea or hypopnea per hours of sleep, respectively. Holter monitoring was done at the same time. The computer used for the sleep study was time synchroniz...
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