Oxygen Desaturation During Sleep Predicts Silent Brain Infarction in Obstructive Sleep Apnea
Oxygen Desaturation During Sleep Predicts Silent Brain Infarction in Obstructive Sleep Apnea Abstract: Background: Obstructive sleep apnea has been identified as a risk factor for stroke. Evidence is increasing that obstructive sleep apnea is a cause of silent brain infarction and that endothelial dysfunction triggered by oxygen desaturation during sleep is the underlying mechanism. Methods: We used a retrospective cohort design to examine the risk of silent brain infarction in 24 obstructive sleep apnea subjects and 24 control subjects. Both cohorts underwent sleep studies, MRI scanning of the brain, determination of C-reactive protein level, and determination of soluble P-selectin levels. Cohorts were comparable in age and BMI. Exclusion criteria included cigarette smoking, hypertension, diabetes mellitus, coronary artery disease, hyperlipidemia, and obesity. Results: There were no silent brain infarcts in the control subjects. Eleven of the 24 subjects with obstructive sleep apnea had a silent brain infarction. The lowest level of oxygen desaturation during sleep was significantly lower in the obstructive sleep apnea subjects with silent brain infarction (66.8 9.2 %) than obstructive sleep apnea subjects without silent brain infarction (82.2 8.0 %). C-reactive protein levels were higher in subjects with silent brain infarction (76.0 52.6 mg/L) than those without silent brain infarction (14.8 56.1 mg/L). Similarly, soluble P-selectin levels were higher in subjects with silent brain infarctions (274.8 89.1 U/ml) than in subjects without silent brain infarction (100.1 47.3 U/l). A logistic regression model confirmed that in obstructive sleep apnea subjects, lowest levels of oxygen desaturation during sleep is predictive of silent brain infarction. Conclusion: Obstructive sleep apnea is a risk factor for silent brain infarction and can cause silent brain infarctions in subjects without traditional stroke risk factors. Among subjects with obstructive sleep apnea, lowest levels of oxygen desaturation during sleep are predictive of silent brain infarction. Oxygen desaturation during sleep may cause endothelial dysfunction that triggers a pro-inflammatory and pro-thrombotic state that is conducive to silent brain infarction.