The Change Of Concentration Of Plasma B-type Natriuretic Peptide Before And After Cardiac Load Test And Its Clinical Significance

Objective:The concentration of plasma B-type natriuretic peptide(BNP) before and after cardiac load test will be measured.The correlation of coronary artery process, metabolic equivalents(METS),age,blood pressure and body weight index with B-type n-atriuretic peptide changes(△BNP) is observed,so as to judge whether the accuracy of treadmill exercise testing diagnosis can be enhanced by the concentration detection of plasma B-type natriuretic peptide.Method:From June 2006 to June 2007,a total of 88 patients with suspected coronary heart disease were referred for treadmill exercise testing and detect of plasma BNP before and after treadmill exercise testing,26 healthy volunteers were enrolled.All the patients were divided into two groups according to arterial stenosis after coronary arteriography:Coronary heart disease group(Group A 46 patients) had above 50% arterial stenosis and no coronary heart disease group(Group B 42 patients) below 50%, with the group of 26 healthy volunteers as the control group(Group C 26 subjects).The testing result was processed with SPSS13.0 statistical software.Result:(1) Plasma B-type natriuretic peptide concentration after treadmill exercise testing increased significantly compared to that before flat plate movement test,with P＜0.001.(2)△BNP of Group A was obviously higher than that of Group B and C,with P＜0.001.(3)△BNP of Group A showed positive correlation with coronary stenosis, metabolic equivalents(METS),diabetes,chest complaint(r=0.645,0.297,0.326,0.361 P＜0.0005,P=0.047,0.026,0.001).△BNP of Group B and C showed positive correlation withmetabolicequivalents(METS)(r=0.341,0.358,P=0.018,0.002). (4) Cut-off point of△BNP concentration of Group A and Group B patients was set by 0.5 pg/ml to make the ROC curve.Area under curve(AUC) was measured in non-parametric method.When△BNP level was set at 10.0pg/ml,the sensibility to coronary artery disease diagnosis was 73.9%,and specificity was 64.2%.When△BNP level at 8.5pg/ml,the sensibility to coronary artery disease diagnosis was 93.5%, specificity 57.1%,positive predictive value 70.5%,negative predictive value 70.5%. And AUC was 0.815.95%confidence interval 0.768～0.896. Conclusion:(1) The concentration of plasma B-type natriuretic peptide after treadmill exercise testing increased obviously.The increases of BNP(△BNP) of Group A was obviously higher than that of Group B and C.(2)△BNP showed positive correlation with metabolic equivalents(METS) and the degree of coronary artery stenosis.(3)△BNP set 8.5pg/ml in treadmill exercise testing had high sensitivity and specificity with coronary artery stenosis diagnosis.(4) Detection of concentration of plasma B-type natriuretic peptide in treadmill exercise testing enhanced the accuracy of concentration diagnosis of plasma B-type natriuretic peptide.