Effect of CPAP on New Endothelial Dysfunction Marker, Endocan, in People With Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is associated with increased cardiovascular (CV) morbidity and mortality. Endocan is a surrogate endothelial dysfunction marker that may be associated with CV risk factors. In this study, we tested whether serum endocan is a biomarker for OSA. Serum endocan levels were measured at baseline in 40 patients with OSA and 40 healthy controls and after 3 months of continuous positive airway pressure (CPAP) treatment in the patients with OSA. All participants were evaluated by full polysomnography. Flow-mediated dilatation (FMD) and carotid intima media thickness (cIMT) were measured in all participants. Endocan levels were significantly higher in patients with OSA than in healthy controls. After adjusting confounders, endocan was a good predictor of OSA. Endocan levels correlated with OSA severity (measured by the apnea-hypopnea index [AHI]). After 3 months of CPAP treatment, endocan levels significantly decreased. Endocan levels were significantly and independently correlated with cIMT and FMD after multiple adjustments. The cIMT and FMD also had significant and independent correlation with AHI. Endocan might be a useful marker for the predisposition of patients with OSA to premature vascular disease.