Distribution Characteristics And Influencing Factors Of Central Blood Pressure And Augmentation Index In Patients With Hypertension

PrefaceAccurate measurement of blood pressure is the most important for us to diagnose and manage the hypertensives and evaluate the prognosis of them.Ordinarily,blood pressure is measured at brachial artery,so we consider the brachial blood pressure as central aortic pressure.But in fact they are not always parallel.Central aortic pressure and the load of left ventricle is determined not only by cardiac output and peripheral resistance,but also by the elasticity or stiffness of large artery and the phase and pressure amplitude of reflecting wave.Clinical trials shows non-invasively determined central aortic pressure predicts cardiovascular risk more sensitively than dose the corresponding brachial blood pressure.So far,non-invasive,validated,and easy to use techniques can estimate central aortic pressure and wave reflection indices.Good consistency of measured central aortic pressure was found between non-invasive device and catheterization.In china,there are limited amount of studies using non-invasive determined central aortic pressure as a clinical index,so it is necessary to investigate the characteristics of central aortic pressure in hypertensives.ObjectiveTo explore the distribution characteristics and influencing factors of central blood pressure and augmentation index in a hypertensive,community-based sample.Method Subjects were drawn from 'the Effect of Economic Antihypertensive Treatment and Prevention from Stroke in Rural Fuxin Liaoning' study.The selecting standard is hypertensive resident aged 35 years old or older according to Chinese guideline for prevention and treatment of hypertension(2005 version).Hypertension was defined SBP≥140mmHg and/or DBP≥90mmHg.The removing standard is the use of antihypertensive drugs within two weeks;secondary hypertension;severe cardiovascular disease;severe hepatic,renal,endocrine and blood disease;known tumor and pregnant woman.The investigation was carried out face to face by training doctors using standardized method with unified questionnaire.The questionnaire included general conditions,history of hypertension and other past disease and correlative treatment.Physical conditions such as height,weight and blood pressure were measured.Blood pressure measurement was using electronic manometer Omron 741C. Central systolic blood pressure and radial augmentation index was determined by non-invasive radial artery pulse wave measurement device(HEM9000AI,Omron-Colin Ltd.Japan).Database was set up by Epidata version 3.0 software and statistical analysis was performed by SPSS version 15.0 software.Measurement data were expressed as mean plus or minus one SD.Significant differences between gender were determined by two-sample t-test.The correlation between two variables is determined by Pearson's correlation.Stepwise multiple linear regression analysis was also performed to determine the factors influencing central systolic blood pressure and radial augmentation index.A value of P<0.05 was considered significant.ResultThe value of central systolic blood pressure and radial augmentation index in females was significantly higher than that in males(both P<0.01),while the differences between gender in subjects beyond 60 years old was not significant after the subjects grouped by age(P>0.05).Age was correlated with central systolic blood pressure and radial augmentation index.(correlation coefficient ranged from 0.12 to 0.39,all P<0.05). Brachial systolic blood pressure was significantly correlated with central systolic blood pressure(correlation coefficient ranged from 0.928 in males to 0.972 in females,both P<0.05).Brachial systolic blood pressure was also correlated with radial augmentation index.Multiple linear regression analysis showed age,gender,height,body mass index, mean arterial pressure,heart rate and systolic blood pressure were independent predictors of central systolic blood pressure and age,gender,height,body mass index, mean arterial pressure,heart rate were independent predictors of radial augmentation index.ConclusionAge,gender,height,body mass index,mean arterial pressure,heart rate and systolic blood pressure were independent predictors of central systolic blood pressure and age, gender,height,body mass index,mean arterial pressure,heart rate were independent predictors of radial augmentation in hypertensives.