Evaluation of carotid artery elasticity in patients with obstructive sleep apnea syndrome using quantitative arterial stiffness technique

Abstract

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. Seventy-two OSAS patients were divided into 2 groups according to whether there was coexisting hypertension. Of them, there were 37 OSAS patients without hypertension (OSAS1 group) and 35 OSAS patients with hypertension (OSAS2 group). 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 (miniSpO(2)), time spent below oxygen saturation of 90% (Ts90%) and oxygen desaturation index (ODI). Correlations and regression were calculated between indices of oxygen saturation and PWV. Compared with normal control group, in OSAS1 and OSAS2 groups, VE and CC were significantly lower, but β and PWV was significantly higher (P < 0.05). Compared with OSAS1 group, CC in OSAS2 group decreased but β and PWV increased significantly (P < 0.05). In the OSAS group, 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. 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.