Part1:Evaluation Of Carotid Artery Elasticity In Patients With Obstructive Sleep Apnea Syndrome Using Quantitative Arterial Stiffness Technique

Objective:(1) To explore the changes and clinical value of carotid elasticity index in patients with obstructive sleep apnea syndrome (OSAS) by quantitative arterial stiffness (QAS) technique.(2) To investigate the relationship between obstructive sleep apnea syndrome (OSAS) and early atherosclerosis using vascular ultrasonography.Methods:Seventy-two OSAS patients were divided into two groups according to whether there was coexisting hypertension or not. Of them, there were37OSAS patients without hypertension (OSAS1group) and35OSAS patients with hypertension (OSAS2group). In addition, forty healthy volunteers were recruited as the normal control group. We measured the arterial elastic parameters including vascular expansibility (VE), compliance coefficient (CC), stiffness index (β) and pulse wave velocity (PWV) through QAS analysis technique. The difference of the parameters among the groups was analyzed. In the OSAS group, polysomnograph (PSG) data were recorded and analyzed including apnea-hypopnea index(AHI), minimal pulse oxyhemoglobin saturation(miniSpO2), time spent below oxygen saturation of90%(Ts90%) and oxygen desaturation index(ODI).Correlations and regression were calculated between indices of oxygen saturation and PWV.Results:(1) Compared with normal control group, in OSAS1and OSAS2groups, VE and CC were significantly lower, but β and PWV were significantly higher (P<0.05). Compared with OSAS1group, CC in OSAS2group decreased but β and PWV increased significantly (P<0.05).(2) In the OSAS group, through Pearson correlation analysis, PWV was correlated positively with systolic blood pressure, AHI, ODI and age(r=0.285～0.542, all P<0.05). Through stepwise multiple linear regression analysis, Age and ODI were the significant variables to determine PWV.Conclusion:The decreases in arterial elasticity are present in OSAS patients. These changes are more evident in OSAS patients with hypertension. QAS technique plays an important role in analyzing the arterial elasticity accurately and could be used as a quantitative mean to evaluate early atherosclerosis. Objective:To investigate the changes of vascular elasticity and endothelium function index in patints with obstructive sleep apnea hypopnea syndrome before and after continuous positive airway pressure (CPAP) treatment for three months.Methods:Thirty-seven OSAS patients without hypertension (OSAS group) and forty normal subjects were enrolled in the study. We measured the arterial elastic parameters including vascular expansibility (VE), compliance coefficient(CC), stiffness index(β) and pulse wave velocity (PWV) through quantitative arterial stiffness (QAS) analysis technique. In addition, Flow-mediated dilation (FMD) was investigated with brachial artery ultrasound examination. The difference of the parameters between two groups was analyzed. In the OSAS group, polysomnograph (PSG) data were recorded and analyzed including apnea-hypopnea index(AHI), minimal pulse oxyhemoglobin saturation(miniSpO2). Correlations and regression were calculated between indices of oxygen saturation and FMD, Twenty patients in OSAS group underwent continuous positive airway pressure(CPAP) treatment for three months.Results:(1) Compared with normal control group, FMD in OSAS group were significantly lower (P<0.05).(2) Through pearson correlation analysis, In the OSAS group, FMD was correlated negatively with AHI, age and β(r=-0.325～-0.378, all P<0.05), but positively with miniSpO2(r=0.504, P<0.01). Through stepwise multiple linear regression analysis, MiniSpO2was a significant determinant for FMD (R2=0.548, P<0.05).(3)Compared with parameters before treatment, there was significant increase in FMD and CC, but the parameters of arterial stiffness including PWV and β were significantly lower(P<0.05).Conclusion:Endothelial dysfunction and the decrease in arterial elasticity are present in OSAS patients, Vascular ultrasonography could be performed in detection of early atherosclerosis. CPAP treatment can improve vascular elasticity and endothelium function effectively.