B型利钠肽在诊断左心衰竭中的价值

The clinical value of B-type natriuretic peptide in the diagnosis of left heart failure

目的 评价B型利钠肽（BNP）在左心衰竭患者中的诊断价值。方法 对243例左心衰竭患者和111例正常人，以荧光免疫的方法测定静脉全血BNP。左心衰竭患者再分为左室射血分数（LVEF）≤40％（n=111）和〉4JD％组（n=132）；心衰代偿组（NYHAⅠ～Ⅱ级，n=110）和失代偿组（NYHAⅢ～Ⅳ，n=133）。比较各组BNP的水平，评价其对左室收缩性心力衰竭的诊断价值。结果 BNP在左心衰竭组显著高于正常组（292．0ng／L vs 17．9ng／L，P〈0．001），在LVEF≤40％组明显高于LVEF〉40％组（471．0ng／L vs 138．5ng／L，P〈0．001），在心衰失代偿组明显高于心衰代偿组（579．0ng／L vs 84．8ng／L，P〈0．001）。BNP在诊断左心衰竭组受试者工作特性曲线下面积（AUC）=0．927、LVEF≤40％组（AUC=0．989）、心衰失代偿组（AUC=0．991）以及区分代偿与失代偿组（AUC=0．941）时的AUC最高，诊断准确性好。以90．0ng／L为阈值点时，诊断有无左心衰、LVEF≤40％和失代偿心衰的阳性预测值分别为98．9％、98．1％和98．5％，阴性预测值分别为64．5％、94．0％和96．5％。以50．0ng／L为阈值点时，诊断LVEF〉40％及代偿心衰的阳性预测值分别为88．0％和84．7％，阴性预测值为72．6％和72．1％。结论 BNP对LVEF严重受损及失代偿性心力衰竭有重要诊断价值。建议临床采用90．0ns／L作为左心衰竭、LVEF≤40％及心衰失代偿患者的诊断阈值；采用50．0ns／L做为LVEF〉40％及代偿心衰的诊断阈值。

Objective To evaluate the diagnostic value of B-type natriuretic peptide （BNP） in the diagnosis of left heart failure （HF） or left ventricular systolic dysfunction. Methods Samples of peripheral venous blood were collected from 243 consecutive patients with left HF and 111 normal controls （ control group, CG） to measured BNP level with fluorescence immunoassay method. The patients with left HF were divided into 2 groups： those with the left ventricular ejection fraction （LVEF）≤40% （n = 111 ） and those with the LVEF〉40% （n = 132） according to the level of LVEF; or into 2 groups： compensated heart failure group （CHF group, at NYHA grade Ⅰ -Ⅱ, n = 110） and decompensated heart failure group （DHF group, at NYHA grade Ⅲ-Ⅳ, n = 133） according to the New York Heart Association （NYHA） functional class. Results The plasma level of BNP of the left HF group was 292.0 ng/L , significantly higher than that of the CG（ 17. 9 ng/L, P 〈 0.001 ）. The plasma BNP of the group with the LVEF≤40% was 471.0 ng/L, significantly than that of the group with the LVEF 〉 40% （ 138. 5 ng/L, P 〈 0. 001 ）. The plasma BNP of the DHF group was 579. 0 ng/L, significantly higher than that of the of the CHF group （ 84. 8 ng/L, P 〈 0.001 ）. The values of area under the curve （AUC） of receiver operator characteristic curve were all 〉 0.9 in the diagnosis of presence of HF（ AUC = 0. 927 ）, HF with the LVEF ≤〈40% （ AUC = 0. 989）, and DHF （AUC =0.991）, and in the differential diagnosis between CHF and DHF （AUC =0.941）. When 90.0 pg/ml was used as cutoff value to diagnose left HF, heart failure with the LVEF≤40% , and decompensation, the positive predictive value （PPV） were 98. 9% , 98. 1% , and 98. 5% respectively, and the negative predictive value （NPV） were 64.5% , 94.0% , and 96.5% respectively. When 50.0 pg/ml was used as the cutoff value to diagnose HF with the LVEF 〉 40% and compensated heart failure, the PPV were 88.0% and 84.7%, the NPV were 72.6% and 72.1% respectively. Conclusion The diagnostic value of BNP is high for the diagnosis of more severely impaired LVEF and decompensated heart failure with 90.0 pg/ml as the cutoff value, and if 50.0 pg/ml is used as the cutoff value, the value is also good for the diagnosis of HF with the LVEF 〉40% and compensated heart failure.