The Relationship Of Vascular Endothelial Function And Carotid Intima-Media Thickness In Prehypertension

Objectives:To observe the circadian rhythm of ambulatory blood pressure of prehypertension, carotid arterial intima-media thickness (IMT) and the brachial arterial endothelial function which displays as flow-mediated dilation(FMD).Methods:104 subjects with prehypertension were divided into two groups according to the circadian rhythm of ambulatory blood pressure monitoring (ABPM):the dipper group (55 cases) and the non-dipper group (49 cases).40 normotensive subjects were enrolled as control group. FMD and IMT were measured by ultrasonography.Results: 1. Compared to the control group, the IMT value of two prehypertensive groups were higher (P<0.05), while the FMD value were lower (P<0.05). The FMD value of dipper group was higher than that of non-dipper group (P<0.05).2. Dipper type and non-dipper type of ambulatory blood pressure of prehypertension accounted for 52.9% and 47.1% respectively. FMD was negatively correlated with IMT significantly (r=-0.843,P<0.001).3. Single-factor correlation analysis showed that:Clinic systolic blood pressure and clinic diastolic blood pressure were negatively correlated with FMD, the difference was statistically significant (P<0.01); clinic systolic blood pressure, diastolic blood pressure clinic,24h SBP, DBP, MAP and age were significantly positive correlated with IMT (P<0.01).4. The stepwise regression analysis where FMD was regarded as the dependent variable showed that systolic blood pressure clinic, clinic diastolic blood pressure, ambulatory blood pressure rhythm were independent factors to FMD. The multiple linear regression equation was concluded in this form:FMD = 18.601 +2.645 X ambulatory blood pressure rhythm type 0.093Xclinic diastolic blood pressure-0.06Xclinie systolie blood pressure (F=188.368, P<0.05). The stepwise regression analysis where IMT was regarded as the dependent variable showed that systolic blood pressure clinic, clinic diastolic blood pressure, FMD, diastolic blood pressure declining rate at night were independent factors to IMT. The multiple linear regression equation was concluded in this form:IMT= 0.199-0.023XFMD+0.003 Xclinic systolic blood pressure +0.003 Xclinie diastolie blood pressure+0.003 Xdeclining rate of nighttime diastolic blood pressure (F 112.227, P<0.05)Conclusion: 1. Compared with normotensive subjects, the prehypertensive subjects had higher IMT value and impaired vascular endothelial function as well.2. Part of prehypertensive subjects had abnormal ABPM rhythm. The vascular endothelial function in non-dipper group was impaired more severely than that in dipper group.3. In prehypertensive subjects, the independent factors of FMD were systolic blood pressure clinic, clinic diastolic blood pressure and ambulatory blood pressure rhythm classification; the independent factors of IMT were clinic systolic blood pressure, clinic diastolic blood pressure, FMD, declining rate of diastolic blood pressure in night time.