N末端B型利钠肽原在陈旧性心肌梗死患者中诊断心力衰竭的价值

目的 评价血浆N末端B型利钠肽原(NT-proBNP)在陈旧性心肌梗死(OMI)患者中诊断失代偿性心力衰竭(心衰)的价值.方法 连续检测586例OMI患者入院时的血浆NT-proBNP浓度.依据NYHA心功能分级标准评价患者的心功能.心衰组为NYHA心功能Ⅱ级、Ⅲ级和Ⅳ级的患者,非心衰组为NYHA心功能I级的患者.通过ROC曲线下面积评价血浆NT-proBNP浓度诊断失代偿性心衰、左心室收缩功能不全和左心室扩大的价值,并找出其诊断失代偿性心衰的切点.结果586例 OMI患者中,男性占80％,年龄25～83岁,平均(58±11)岁.NYHA Ⅰ级374例、Ⅱ级99例、Ⅲ级82例、Ⅳ级31例,其血浆NT-proBNP浓度[中位数(第25百分位数,第75百分位数)]分别为[484.7(381.6,647.8)pmol/L、907.6(516.6,1290.3)pmol/L、1420.2(879.5,2336.2)pmol/L2442.6(1695.4,3670.7)pmol/L,P＜0.01].心衰组(212例)血浆NT-proBNP浓度显著高于非心衰组(374例)[分别为1148.2(707.9,2145.3)pmol/L和484.7(381.6,647.8)pmol/L,P＜0.01].60岁以上的OMI患者的血浆NT-proBNP显著高于＜60岁的患者[分别为702.3(472.4,1208.5)pmol/L和526.6(392.1,855.6)pmol/L,P＜0.01].男女性别间比较差异无统计学意义.血浆NT-proBNP诊断失代偿性心衰的ROC曲线下面积是0.844(95％ CI:0.809～0.880,P＜0.01).根据ROC曲线,将NT-proBNP诊断失代偿性心衰的切点值定为700 pmol/L,大于或等于此值时诊断心衰的敏感性、特异性和准确性分别是75.9％、79.9％和78.3％,阳性预测值和阴性预测值分别为67.9％和85.3％.对于＜60岁患者,该切点值以600 pmol/L最佳,对于≥60岁患者,该切点值以800pmol/L为最佳.结论 血浆NT-proBNP是OMI患者中诊断失代偿性心衰的可靠指标.对≥60岁和＜60岁的患者应采取不同的诊断切点.

Value of plasma NT-proBNP for diagnosing heart failure in patients with previous myocardial infarction

Objective The study aimed to evaluate the value of plasma NT-proBNP in diagnosing heart failure in patients with previous myocardial infarction.Methods Plasma concentration of NT-proBNP was measured in patients with previous myocardial infarction by ELISA method at admission.Patients were divided into non heart failure group(NYHA class I)and heart failure group(NYHA class Ⅱ-Ⅳ).The NT-proBNP levels were compared between NYHA class Ⅰ,Ⅱ,Ⅲ and Ⅳ,and between heart failure group and non heart failure grou.ROC analyses were performed to evaluate the diagnosing value of plasma NT-proBNP for heart failure and to identify the optimal cut-off point for diagnosing heart failure patients.Results Total 586 patients[aged from 25-83(58 ± 11)years,80％ male]with previous myocardial inffarction were enrolled in his study(n =374 of NYHA class Ⅰ,n =99 of NYHA classes Ⅱ,n =82 of NYHA class]Ⅲ,n =31 of NYHA class Ⅳ).Plasma NT-proBNP levels in these four NYHA classes were 484.7(381.6,647.8)pmol/L,907.6(516.6,1290.3)pmol/L,1420.2(879.5,2336.2)pmol/L,2442.6(1695.4,3670.7)pmol/L,respectively(P ＜0.01).The plasma NT-proBNP level in heart failure group wassignificantly higher than in non heart failure group[1148.2(707.9,2145.3)pmol/L vs.484.7(381.6,647.8)pmol/L,P ＜0.01].Plasma NT-proBNP level in patients with age≥60 years was significantly higher than patients with age ＜ 60 years[702.3(472.4,1208.5)pmol/L vs.526.6(392.1,855.6)pmol/L,P＜0.01].ROC analysis showed that the area under the curve(AUC)for diagnosing heart failure was 0.844(95％ CI: 0.809-0.880,P ＜ 0.0l),the optimal plasma NT-proBNP cut-off point for diagnosing heart failure was 700 pmol/L with a sensitivity of 75.9％,a specificity of 79.9％,an accuracy of 78.3％,a positive predictive value of 67.9％ and a negative predictive value of 85.3％.The optimal plasma NT proBNP cut-off point was 600 pmol/L for patients ≥60 years old and 800 pmol/L for patients ＜ 60 years old.Conclusion Plasma NT-proBNP level is a valuable parameter for diagnosing hemt failure in patients with previous myocardial infarction.