The Relationship Between Hs-CRP And Nt-Probnp And Blood Pressure Variability In Hypertensive Patients

Preamble:Hypertension is the most important risk factors of cardiovascular diseases.Clinical research had proved that not only the increase of blood pressure wouldcause cardiovascular and cerebrovascular events. Moreover, blood pressurevariability was also an independent risk factors of cardiovascular andcerebrovascular events. It is not yet completely clear that how blood pressurevariability leads to cardiovascular and cerebrovascular events. Themechanisms of target organ damage caused by abnormal blood pressurevariation may include direct damage to vascular endothelium, the start of theinflammatory response, and RAAS activation. Therefore, we infer that bloodpressure variability may lead to changes of the levels of hs-CRP and NT-proBNP, vice versa, serum hs-CRP and NT-proBNP level may reflect thevariability of blood pressure. No studies about the relationship betweenhs-CRP and NT-pro BNP levels and blood pressure variability have beenreported in essential hypertension patients.The purpose of this study is toinvestigate the relation between serum hs-CRP and NT-proBNP level andblood pressure variability, and clarify the predictive value of serum hs-CRPand NT-proBNP level on blood pressure variability.Objective：(1) To Explore the correlation of the high-sensitive C-reactive protein(hs-CRP) and N-terminal pro brain natriuretic peptide (NT-proBNP)levelandblood pressure variability in essential hypertensive patients;(2) Todetermine the predictable value of hs-CRP and NT-proBNP to hypertensionblood pressure variation (BPV).Methods：From September2010to March2012,66patients with essentialhypertension were recruited into this study as case group, including35malepatients and31female patients, with age range of46～79years old, mean age 60.9±9.7years old. All the patients tallied with the diagnosis criteria made byGuideline of Prevention and treatment of hypertension of China. Patientscombined with secondary hypertension, coronary heart disease, heart valvedisease, cardiomyopathy, heart failure, stroke, peripheral ascular disease, stressstate, acute or chronic inflammation, chronic obstructive pulmonary disease,diabetes, kidney and liver dysfunction and endocrine diseases, which mayaffect hs-CRP and NT-proBNP level were not involved in the case group. Atthe same period,39healthy volunteers were selected as control group (male21and female18), with age range of50～75years old, mean age60.0±8.0years old. All participants in the study were conducted a comprehensivephysical examination and detailed data were recorded.The ambulatory bloodpressure monitoring was performed to obtain blood pressure variationcoefficient.5ml of venous blood was collected and centrifugated at3000r/min for15min to acquire serum. The serum hs-CRP level was measuredusing immunoturbidimetry method (Kits were bought from Wuhan ZhongtaiBiotech Co., LTD.). Chemical luminescence method was applied todetermine the serum NT-proBNP content (Kits were bought from Roche Co., LTD). The variability indices of blood pressure,including24h systolic bloodpressure variation coefficient,24h diastolic pressure variation coefficient,daytime systolic blood pressure variation coefficient, daytime diastolicpressure variation coefficient, and nighttime blood pressure variationcoefficient were derived automatically.Results：(1) BPV of patients with primary hypertension was significantly higherthan that of the control group (p<0.05).24h BPV and daytime systolic BPVwere significantly higher in high CV group than those in low CVgroup(p<0.05). These was no significant difference in daytime diastolic BPVand nighttime BPV between high CV group and low CV group.(2) Serumhs-CRP and NT-proBNP level were significantly higher in case group thanthose in control group (p<0.05for both). Also, the hs-CRP and NT-proBNPlevel in high CV group were significantly higher than those in low CVgroup(p<0.05for both).(3) Linear correlation analysis showed that the serumhs-CRP and NT-proBNP level correlated significantly and positively with,24h BPV, daytime BPV and nighttime systolic BPV (p<0.01for all).(4) A multiple stepwise regression analysis demonstrated that total cholesterol and24h systolic blood pressure variability were significantly and independentlyrelated with serum hs-CRP levels (regression coefficient were0.560and0.258,P=0and0.048). Total cholesterol,24h diastolic blood pressure variability andage had significantly positive correlation with serum NT-proBNP levels(regression coefficient βrespectively0.444,0.390and0.308, the P values were0.001,0.006and0.016).Conclusions：(1) Increased blood pressure variation is an important clinicalmanifestation of primary hypertension, and it can reflect the severity of thehypertension.(2)24h systolic blood pressure variability was independently andpositively related to serum hs-CRP level, and24h diastolic blood pressurevariability had significantly positive correlation with the serum NT-proBNPlevel.