Relationship Between Obstructive Sleep Apnoea, Oxygen Desaturation and Cardiovascular Risk

Obstructive sleep apnoea syndrome (OSAS) increases the risk cardiovascular events regardless of the presence of previous cardiovascular disease. As both OSAS and coronary heart disease (CHD) have same risk factors it's often difficult to quantify the proportion of each risk factor in developing cardiac events. The aim of this study was to evaluate the 10-year risk of developing a coronary heart disease (CHD) event or stroke in newly diagnosed OSAS patients. 65 patients diagnosed with OSAS over a period of four months in Oradea Sleep Laboratory were included. Demographic characteristics, anthropometric parameters, clinical and biochemical data, sleep disorder and daytime sleepiness assessment, results of polysomnography were collected in all patients. In 55 selected patients by age range from 34 to 74 years old, cardiovascular risk was assessed using Framingham score calculator. Statistical analysis was performed using SPSS-PC version 7.5 and Stata 10. The estimated 10-years risk of a CHD event was 18.97% (+/- 9.67) in all cases. It was higher in men (22.17% +/- 9.24) compare to women (12.39% +/- 6.92) and it was not significantly different by stages of OSAS severity (20.58% +/- 9.41 in patients with severe OSAS versus 15.4% in mild OSAS), suggesting that apnea hypopnea index is not a major confounding factor. Desaturation of oxygen is a better outcome to define the relation between OSAS and cardiovascular diseases. OSAS and cardiovascular risk factors increased risk for future adverse cardiovascular events related to the severity of oxygen desaturation.