The Study On Elasticity Of Carotid Artery In Patients With Metabolic Syndrome By Using Velocity Vector Imaging

ObjectiveDetecting the carotid artery wall intima-media thickness (IMT), velocity, strain and strain rate in patients with metabolic syndrome (MS) by using velocity vector imaging (VVI), to assess the elasticity change of carotid artery early and noninvasively. Providing the basis of artery structure and function change in MS patients for clinical.Methods50patients (male28, female22, average age40.1±10.9years old) with MS were enrolled in the research as MS group. The diagnostic criteria of MS was in line with the Chinese Diabetes Society (CDS) in2004. Addition50cases (male30, female20, average age42.4±10.8years old) whose age and gender were matched with MS patients were selected as non-MS group. All the patients with the immune system disease, blood disease, thyroid disease, severe liver and kidney dysfunction, severe infectious disease, type I and secondary diabetes, secondary hypertension, hypertrophic and dilated cardiomyopathy, peripheral arterial thrombosis, Takayasu arteries were excluded. The cases with a poor quality ultrasound images also be removed. Their age, gender, height, weight, body mass index (BMI) were recorded. The sitting right brachial artery systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. The laboratory parameters included fasting blood glucose (GLU), triacylglycerol (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and uric acid (UA). VVI was performed with Siemens Sequoia-512, equipped with VVI analysis software and15L8linear array probe, the frequency is8.0-14.0MHz. Patients were supine, neck fully exposed, connected with the synchronous electrocardiogram (ECG). Asked the patients hold their breath for several seconds, short axis dynamic images1.5-2.0cm away from the bifurcation were captured for3continual heart beating cycles. The IMT was measured at the same position. Entering the VVI automatic analysis software, the maximum of velocity (Vmax),maximum of strain (Smax),and maximum of strain rate (SRmax) of four segment (anterior wall, medial wall, lateral wall and posterior wall) were measured. The data were analyzed and processed.Results 1. The age and sex composition between the two groups showed no significant difference(p>0.05).2. The BMI, SBP, DBP, fasting blood GLU, TC in MS group were higher than that in non-MS group (p<0.05). The TG, LDL-c, UA and HDL-c in MS group and non-MS group showed no statistically significant difference (p>0.05).3. The IMT in MS group was thickener than that in non-MS group, but there was no statistically significant between the two groups (p>0.05).4. The Vmax, Smax and SRmax in MS group were lower than that in non-MS group (p>0.05).5. whether MS group or non-MS group, the common carotid artery wall peak systolic velocity (Vs) of anterior wall and lateral wall was higher than that of medial wall and posterior wall (p>0.05). The difference between the anterior wall and lateral wall or the medial wall and posterior wall showed no significant (p>0.05).6. Smax or SRmax of every wall in two groups is numerical approximation, a good consistency was showed between two groups.7Correlation analysis of the composition of MS with carotid elastic showed that carotid SR was related to age, SBP, DBP, BMI, fasting blood GLU, TG, TC negatively; carotid SR had no obvious linear correlation with LDL-c, LDL-c and UA. There was a significant negative correlation in SR with age (r=-0.680, p<0.001), SBP (r=-0.399, p<0.001), FBG(r=-0.355, p<0.001), TG(r=-0.352, p<0.001). Carotid strain rate of posterior wall as the dependent variable, the above parameters as independent variables, multiple stepwise regression analysis found that Age, SBP, TG, GLU were independent factors affect carotid strain rate.Conclusions1. While there was no significant IMT thickening in the MS group, the elasticity of carotid artery in MS patients decreased significantly, indicating that the arterial elasticity has been reduced before the arterial structure change.2. Age, SBP, TG and fasting blood GLU are independent risk factors of carotid artery elasticity change in MS patients.3. VVI is a convenient, noninvasive, quantitative method that reflects the hardening of the arteries. It has obvious advantages in the early evaluation of vascular elasticity.