PURPOSE:The mobility of cardiovascular diseases increased in patients of obstructive sleep apnea syndrome (OSAS). Endothelial dysfunction had been considered as one of the pathophysiologic mechanisms. Endothelium-Dependent Flow-Mediated Dilation (FMD) and NOx (nitrate and nitrite (NOx)) level in peripheral venous blood have been demonstrated to reflect endothelial function. The purpose of this study was to evaluate whether there is an abnormal endothelial function in patients of OSAS and the effect of nasal CPAP therapy on endothelial function in patients of OSAS.
METHODS:Twenty patients with moderate or severe OSAS (OSAS group) were included to receive nasal CPAP treatment. All subjects also underwent blood pressure, simple spirometric, arterial blood gas (ABG) measurements, endothelial function and an overnight polysomnography sleep study before and after 2 months nasal CPAP treatment. Endothelial function examination includes NOx (nitrate and nitrite (NOx)) level in peripheral venous blood samples measured by using a nitrite/nitrate assay kit and FMD measured by high-resolution B-mode ultrasonography. Ten subjects without OSAS served as controls (control group).
RESULTS:Results showed that subjects with OSAS before nasal CPAP treatment had lower NOx levels (14.6 ± 5.9 αM) and lower FMD (5.2 ± 4.2 %) when compared with subjects without OSAS (NOx: 30.5 ± 7.2 αM); (FMD: 13.2 ± 3.9 %). Subjects with OSAS had significant increase in NOx levels (28.9 ± 6.1 αM) and FMD (12.7 ± 4.1 %) after 2 months of nasal CPAP treatment.
CONCLUSION:In conclusion, moderate to severe OSAS patients before nasal CPAP treatment had lower FMD and NOx levels when compared with normal control. These abnormalities can be improved after 2 months of nasal CPAP treatment.
CLINICAL IMPLICATIONS:OSAS patients had endothelial dysfunction. These abnormalities can be improved after nasal CPAP treatment.
DISCLOSURE:Ching-Chi Lin, No Financial Disclosure Information; No Product/Research Disclosure Information