B-Type Natriuretic Peptide And Prognosis In Patients With ST-Segment Elevation Myocardial Infarction

PrefaceAcute myocardial injury is the serious disease which can be decrease in mortality for early determination and early treatment.So it is very important to asses the risk and to prognosticate the occurrence of heart event.Recently,there are many studies that indicated B-type natriuretic peptide(BNP)can be used to estimate the risk of heart event after acute myocardial injury.When plasma BNP was significantly high in patient with AMI,it would be worth to evaluate the predicament and prognosis.At the early time of AMI,BNP level began to elevate just as other marker changed within normal range,it was due to local myocardial infarction and mechanical stress that stimulate BNP to release.Therefore BNP was a strong non-invasive forecast factor that reflected survival myocardial function at early time of AMI.It has been reported the value of BNP in prognosis where the plasma concentration raised rapidly over 24 h after ST-segment elevation myocardial infarction(STEMI)When measured two to seven days after infarction,elevated levels of BNP identify patients with lower survival. Because of the time-dependent rise in BNP,the value of very early determinations is less clear,and there are sparse data addressing the prognostic implications of BNP drawn at the time of presentation with STEMI.Therefore,in my study was,I determined the plasma BNP concentration in patient with STEMI 10 hours after the onset of chest pain to evaluate BNP along and in comparison to cardiac tropnin I and high-sensitivity C-reactive protein prognosisMaterials and Methods1.Materials(1)Study populationThe trial randomized 58 patients with ST-segment elevation myocardial infarction, and the control group came from 30 health medical examination.(2)ReagentBNP kit,BNP calibrator,BNP control,TnI kit,TnI calibrator,TnI control,hsCRP kit,hsCRP calibrator,hsCRP control.(3)ApparatusAxSYM auto immune analytic instrument,Access auto immune analytic instrument,BNⅡauto immune analytic instrument,low temperature super centrifuge.2.Methods(1)Specimen CollectionAll the blood samples were obtained presenting within 10h.B-type natriuretic peptide was collected in EDTA anticoagulant plasma and stored in the condition with -20℃after centrifuging.Troponin I and High-sensitivity testing for CRP was collected in serum which was separated by apart-glue,and also stored in the condition with -20℃.(2)DeterminationB-type natriuretic peptide was measured by AxSYM auto immune analytic instrument with the principle of chemiluminescent enzyme immunity.Troponin I was measured using Access auto immune analytic instrument.High-sensitivity testing for CRP was performed using a Dade-Behring immune chemiluminescent assay.(3)Information Collection and Follow-upThe clinical information for patients with STEMI was collected by investigator with the uniform criterion,and the patient was tracked with telephone or communication and so on in six months.The patients were recorded the occurrence of myocardial event in the following-up months.(4)Statistical analysisAll the data were analyzed by software package of SPSS11.0.The concentration of BNP was categorized into dichotomized using a prespecified decision limit (80pg/ml).An exploratory evaluation of additional cut-points was performed using receiver-operating characteristics(ROC).The baseline characteristics of patients with and without elevated BNP were compared using the Wilcoxon rank-sum test for continuous variables.Multivariate analyses of the association between BNP and outcomes were performed using logistic regression.Result1.BNP levels in patient with or without STEMI and Association with clinical outcomes.The median concentration of BNP 10 hours after the onset of chest pain in patient with STEMI was 116.2 pg/ml and 40.7pg/ml in patient of control group,the BNP levels in patient with STEMI were significantly higher than patient in control group(P＜0.01). Elevated levels(＞80 pg/ml)were older and more likely to have a history of hypertension,angina,and CHF(P＜0.01).The proportion of patients with elevated BNP did not differ between men and women.The median time from symptom onset was longer in patients with elevated BNP(P＜0.01).2.BNP and prognosis for patient with STEMIIn addition to evaluating the prespecified decision limit,we performed an exploratory analysis of alternative cut-points.The ROC analysis indicated an optimal cut-point in this data set of＜80 pg/ml,a nearly five-fold higher risk of death/CHF The baseline concentration of BNP,and the predictive value of a negative test is 94.1%. The plasma BNP＞80 pg/ml was associated with a significantly higher risk of death through 6 month(P＜0.01).3.Comparison BNP with cTnI,hsCRP for prognosis for patient with STEMI.Compared with cTnI and hs-CRP,BNP was a substantially more robust marker of 6-months mortality.However,cTnI and hs-CRP did not offer prognostic information independent of BNP.In contrast,BNP maintained an independent contribution to risk assessment.4.Multivariate logistic regression analyses.Assessed using logistic regression,BNP remained independently associated with mortality(OR:7.2,95%confidence interval[CI]2.1 to 24.5,P＜0.01),as well as major clinical predictors of mortality(age,anterior MI location,time from symptom onset, heart rate,blood pressure,history of CHF.Conclusion 1.The BNP levels in patient with STEMI were significantly higher than patient of control group and there are significantly connection between BNP levels and age, history of hypertension,angina,time from symptom onset.2.The ROC analysis indicated an optimal cut-point in this data set of＜80 pg/ml, The plasma BNP＞80 pg/ml was associated with a significantly higher risk of death through 6 months.3.cTnI and hs-CRP did not offer prognostic information independent of BNP.In contrast,BNP maintained an independent contribution to risk assessment.