الفهرس 
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Abstract
OSA syndrome is defined by five or more respiratory events apneas, hypopneas, or RERAs-in association with excessive daytime somnolence; waking with gasping, choking, or breath holding; or witnessed reports of apneas, loud snoring, or both. Each episode of apnea or hypopnea must last a minimum of 10 seconds, is commonly accompanied by reductions in blood oxygen saturation of at least 3% to 4%, and is usually terminated by brief, unconscious arousals from sleep. Snoring between apneas is a frequent complaint of bed partners and is often the symptom that prompts these patients to seek medical attention, although excessive daytime somnolence is a common initial complaint. Automobile accidents and increased cardiovascular morbidity and mortality are frequent complications if OSA is left untreated. Many OSA sufferers complain of awakening from sleep with morning headache, sore throat, and fatigue or a feeling of being un refreshed regardless of the duration of sleep. OSA is exacerbated by ingestion of alcohol, sedative use, and weight gain. The American Academy of Sleep Medicine classifies mild OSA as 5 to 15 events per hour, moderate as 15 to 30 events, and severe as 30 events or more.
A number of negative health effects have been attributed to untreated OSA including increased mortality, an increase in cardiovascular disease, and neurocognitive difficulties. In a retrospective study, He and colleagues found that untreated OSA patients with an apnea index (AI) greater than 20 had a statistically significant increase in mortality compared with patients with an AI less than 20, and they also found that untreated patients with an AI greater than 20 had a 63% probability of surviving 8 years, compared with 96% in those with an AI less than 20. Additionally, untreated OSA is reported to increase the risk of fatal and nonfatal motor vehicle accidents by 2.5-fold. A significant proportion of the mortality and morbidity related to OSA occurs through its effects on the cardiovascular system, which can result in hypertension, coronary heart disease, congestive heart failure, arrhythmias, pulmonary hypertension, stroke, and sudden death. Untreated moderate and severe OSA has been reported to result in a threefold increase in fatal and nonfatal cardiovascular events, compared with both healthy men without OSA and men with CPAP treated OSA. Treatment of OSA with CPAP has also been reported to lower blood pressure by 10 mm Hg.
CPAP is considered the gold standard of treatment for moderate to severe OSA. Studies have demonstrated its effectiveness in reducing the AHI and in subjectively improving sleep quality; however, patient adherence remains a significant obstacle. CPAP acts as a pneumatic splint that prevents upper airway collapse by providing constant positive intraluminal pressure during inspiration and expiration. Numerous effects of CPAP treatment have been described, chief among these being the reduction in AHI, improvement in objective and subjective sleepiness, improvement in overall quality of life, reduction in risk of cardiovascular events, and reduction in the risk of motor vehicle accidents.
Recently, interest has also surrounded the beneficial effects of CPAP on cardiovascular health as a result of decreased inflammation, as measured by a decrease in the inflammatory markers C-reactive protein and interleukin-6; improved endothelial function; and reduced diurnal sympathetic activity.
The aim in this study is trying to find the answer of the following question: Does obstructive sleep apnea have an effect on cardiovascular diseases?
To achieve this aim the researcher has done a meta-analysis which included four studies comparing between treated with CPAP and untreated OSA patients as regard occurrence of CVS disease in both groups.
The result of meta-analysis showed increased risk of CVS disease in the untreated group in comparison to the treated group with CPAP.
To provide solid evidence, a double-blind randomized trial is needed, with adequate follow up time for a better evaluation of relationship between obstructive sleep apnea and the incidence of cardiovascular diseases.