Correlation Of Serum Uric Acid Levels And Carotid Plaques And Arterial Stiffness In Patients With Essential Hypertension

ObjectiveTo study the correlation of serum uric acid(UA) levels with carotid plaques asand arterial stiffness in patients with essential hypertension(EH). To explore thepredictive value of serum uric acid in preclinical essential hypertension. Moreover toanalysis the role of serum uric acid in increased arterial stiffness in essentialhypertension(EH).MethodA cross-sectional study method was used and254followed-up subjects agedfrom37-79years were enrolled. All254cases were complete data. After informedconsent to accept ultrasound and PWV examinations were168cases and92cases ofexaminations with essential hypertension(EH).With92cases of essential hypertensionpatients as high blood pressure group,40males and52females with average age of66.02±6.42. The healthy control group of30cases, including15males and15females with average age of64.73±9.06. All the subjects were lined questionnairesurvey, and then measured the blood pressure, heart rate(HR), height, weight, waistcircumference(WC),hip circumference(HC), and tested total cholesterol(TC),triglycerides (TG),high density lipoprotein cholesterol (HDL-C),low densitylipoprotein cholesterol (LDL-C), fasting blood glucose (FBG),high sensitivityC-reactive protein (hsCRP),uric acid (UA) and other indicators. After signed the informed consent, B-mode ultrasound examination were performed which includingthe measurement of CCA-IMT and the sites of plaque in the ICA ECA and CBs.Hypertensive patients with carotid plaques according to the semi-quantitative scalescore to assess the severity of plaques, divided into three groups with1,2,3grade. Inaddition they were also divided into two groups: rigid plaque group and soft plaquegroup based on their echocardiography. Arterial stiffness was assessed by the FrenchKangPuLe atherosclerosis measurement instrument, which including the measurementof carotid femoral arterial pulse wave velocity(CFPWV), carotid radial artery pulsewave velocity(CRPWV) and carotid distal arterial pulse wave velocity(CDPWV),respectively, as a reflect central arterial elasticity and peripheral arterial stiffnessindex. According to the result of CFPWV, the hypertensive patients were devided intotwo groups, group CFPWV<9m/s(normal group) and group CFPWV≥9m/s(abnormal group). Pearson correlation analysis and a multivariate linear regressionanalysis were used to find the independent factors for CFPWV and CRPWV. Allstatistical analyses were performed using the SPSS17.0software.Results1. Hypertension group compared with control group1.1The general clinical features of hypertension group and control groupparametersCompared the two groups, parameters of age, gender, heart rate, waist-hip ratio,high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, CRPWV,CDPWV showed no significant differences(P>0.05); But blood pressure(systolicblood pressure, diastolic blood pressure and pulse pressure), body mass index, totalcholesterol, triglyceride, low-density lipoprotein cholesterol, fasting blood glucose,uric acid, IMT and CFPWV in hypertension group were significantly higher thanthose in the control group and there were statistically significant differences in thetwo groups(P<0.05).1.2Abnormal rate of IMT and CFPWV in Hypertension group and controlgroupMean values and abnormal rate of IMT (0.69±0.14,42.39%) and CFPWV (12.81±3.68,86.96%) in hypertension group and control group were significantdifferences (P=0.000).2. Comparison of clinical parameters and the UA among the different levels ofplaque groups in hypertension patientsIn92patients with essential hypertension,45cases had carotid plaques.According to the semi-quantitative scale score to assess the severity of plaques, the45cases were divided into three groups with1,2,3grade. UA values in the three groupswere285.25±78.41,341.19±63.99,401.33±88.49, and IMT values in the threegroups were0.62±0.09,0.71±0.14,0.82±0.10. The3grade group had significantlyhigher UA and IMT values than the2grade group (P<0.05) and1grade group(P<0.05), while the2grade group also had significantly higher UA and IMT valuesthan the1grade group (P<0.05). Three groups of UA and IMT with carotid plaqueslevels rise higher and higher.3. Comparison of clinical parameters and the UA between rigid plaque groupand soft plaque group in hypertension patientsIn45cases of carotid plaque patients,34cases were rigid plaques patients and11cases were soft plaques patients. Compared the two groups, uric acid value in softplaque group was significantly higher(389.00±69.45umol/L vs323.03±72.71umol/L，P=0.012) than that in rigid plaque group and there was statistically significantdifferences in the two groups(P<0.05). The other cardiovascular risk factors betweenthe two groups had no significant differences.4. Comparison of clinical parameters between carotid-femoral pulse wavevelocity (CFPWV) normal group and abnormal groupIn abnormal group age, systolic blood pressure, pulse pressure, uric acid weresignificantly higher than those in normal group and there were statistically significantdifferences in the two groups(P<0.05). But gender, diastolic blood pressure, heart rate,body mass index, waist-hip ratio, total cholesterol, triglyceride, high-densitylipoprotein cholesterol, low-density lipoprotein cholesterol, fasting blood glucose,high-sensitivity C-reactive protein showed no significant differences(P>0.05). 5. Correlation between pulse wave velocity(PWV) and clinical characteristicsCFPWV was significantly correlated with age（r=0.414,P <0.001）, systolicblood pressure（r=0.224,P=0.033）, pulse pressure（r=0.270,P=0.010）, uric acid（r=0.219,P=0.038）, while CRPWV was significantly correlated with systolic bloodpressure（r=0.293,P=0.005）,diastolic blood pressure(r=0.214,P=0.042), pulse pressure（r=0.210,P=0.046）,total cholesterol(r=0.228,P=0.030),low-density lipoproteincholesterol(r=0.320,P=0.002), uric acid（r=0.244,P=0.020）.6. Multiple linear regression analysis between pulse wave velocity(PWV) andclinical characteristicsA stepwise multiple linear regression analysis demonstrated that age(P<0.01),systolic blood pressure(P<0.01), pulse pressure(P<0.01), uric acid(P<0.01) werepredisposed factors for higher CFPWV (R~2=0.883), while low-density lipoproteincholesterol(P<0.01) and uric acid(P<0.01) were factors predictive for higher CRPWV(R~2=0.271). Using multiple linear regression analysis controlling for LDL-C, UAwas still independently correlated with CRPWV(r=0.292，P=0.005).Conclusion1. The parameters of PP, BMI, TC, TG LDL-C, FBG, UA, IMT CFPWV inhypertension group were significantly higher than those in the control group, whichcan be used as susceptible indicators of the occurrence and development ofhypertension. Carotid atherosclerosis and arterial stiffness compared with controlgroup were also significantly higher. So regular ultrasound of carotid artery detectionand PWV detection could be used as detective methods in hypertensivearteriosclerosis.2. In hypertensive patients serum UA levels and the degree of carotid atherosclerosis andplaque are closely related. UA is an independent risk factor of atherosclerosis. The serum UAlevel may reflect the stability of carotid atherosclerotic plaque. Prompt that serum uric acidmay be involved in the pathophysiology of atherosclerosis process.3. The increased serum UA levels is closely related to the increased arterial stiffness in essentialhypertension. UA is an important factors of CFPWV and independently related to CRPWV.Prompt that serum uric acid may be a potential mechanism for hypertension and othercardiovascular events.