The Utility Of Plasma NT-proBNP Level For The Diagnosis Of Heart Failure In Patients With Acute Dyspnea

Background：Acute dyspnea is a critical medical emergency syndrome. Heartfailure as a common reason of it is lack of a convenient, quick and effective diagnosemean. Natriuretic peptide(NP), as a biomarker which committed to regulate thebalance of water and salt and promote vasodilation, was increased in order tomaintain the relative stability of the circulation system. Recently, as a member ofnatriuretic peptide family, amino-terminal B-type natriuretic peptide precursor(NT-proBNP) is a biomarker to diagnosis heart failure, its application is popular all overthe world and is supported by many laboratory and clinical researches. However,many factors affect the results, the clinical application is complexed, these problemsneed more deep and extensive researches.Objective：To assess the utility of plasma NT-proBNP level for the diagnosis ofheart failure in patients with acute dyspnea and investigate its value after stratified byage. To explore the relationship between NT-proBNP and heart failure-related clinicalindicators.Methods：From February2011to2012, the level of plasma NT-proBNP wasdetermined for216acute dyspnea patients with cardiac disease or non-cardiac diseasein our hospital. According to other clinical information such as the results ofechocardiography divided all patients into heart failure group (118cases) andnon-heart failure group (98cases). By age of all patients were divided into108casesof the elder group (≥70years) and younger group of108cases (<70years). Analysisthe diagnosis value of NT-proBNP in heat failure by ROC (receiver operatingcharacteristic) curve in all cases group, elder group and younger group. Comparativethe changes of diagnostic value of NT-proBNP by age stratification. At the meantime,take advantage of the fourfold table to evaluate the diagnostic tests in the elder groupand the younger group. Analyze the correlation between NT-proBNP and other heartfailure-related indicators such as LVEF, NYHA (New york heartfunction assessment).Reveal the changes of plasma NT-proBNP level in patients with heart failure.Results：When the younger, elder group compare to all cases groups, the area under ROC curve of NT-proBNP diagnose heart failure is increased（0.889,0.862VS0.859）, the Optimal cut-points for diagnosis is decrease (1289.6ng/L,1821.75ng/LVS1874.40ng/L), Youden’s index (correct diagnosis index) is increasd (0.682,0.615VS0.594). Defined points to1800ng/L in the older group as a diagnostic, the totalcoincidence rate to diagnosis of heart failure is the highest rate (79.6%), thecorresponding sensitivity, specificity, positive predictive value, negative predictivevalue were90.6%,70.9%,75.0%,88.6%; to1200ng/L in the younger group as adiagnostic, the total coincidence rate to diagnosis of heart failure is the highestrate(86.1%), the corresponding sensitivity, specificity, positive predictive value,negative predictive values were95.4%,72.1%,83.8%,91.2%. In all cases, plasmaNT-proBNP level in patients with heart failure was significantly higher than it in thepatients without heart failure (p <0.001).In different class of NYHA, NT-proBNPlevel is significant difference (p <0.001), between groups comparison there are alsostatistically significant difference (p <0.05). the difference between the NT-proBNPlevel in male group and female group is no significant different (p=0.627); oldergroup and younger group of NT-proBNP level is no significant difference (p=0.155).NT-proBNP and LVEDD (r=0.650), serum uric acid (r=0.649), heart rate (r=0.585),serum creatinine (r=0.449), unconjugated bilirubin (r=0.367), blood urea nitrogen(r=0.345), total bilirubin (r=0.339), age (r=0.268) were positively correlated; withLVEF (r=-0.794), systolic blood pressure (r=-0.292), diastolic blood pressure (r=-0.190), hemoglobin (r=-0.152) was negatively correlated.Conclusion：The dignosis value of plasma NT-proBNP level in heart failure patientswith acute dyspnea is obvious, stratified for age, its diagnostic value has been furtherimproved. Plasma NT-proBNP level in heart failure patients is significantly elevated,Plasma NT-proBNP level and age is positively correlated, It also correlate with manyother heart failure-related clinical factors.