[The relationship between plasma BNP level and the left ventricular dysfunction parameters in patients with acute myocardial infarction and it's value in diagonosing heart failure.].

OBJECTIVE: To explore the correlation between plasma BNP level and left ventricular dysfunction parameters in patients with acute myocardial infarction (AMI). METHODS: Plasma BNP level was determined in 230 consecutive inpatients with AMI and 111 normal controls. Patients were grouped according Killip grades, LVEF and LVEDd, respectively. BNP was transformed into lnBNP for the normal distribution. The receiver operator characteristic curve (ROC curve) was drawn to determine the best threshold and criteria for diagnosing heart failure. RESULTS: After AMI, lnBNP levels increased significantly in proportion with increasing Killip grades (I-III), and decreasing LVEF (all P < 0.05). lnBNP level was significantly higher in LVEDd > 55 mm group than in the LVEDd < 55 mm group (P < 0.01). lnBNP, LVEDd and LVEF all linearly correlated with Killip grades (P < 0.05) and the best correlation was shown between lnBNP and Killip grades (r = 0.53, P < 0.05). lnBNP also positively correlated with LVEDd (r = 0.17, P < 0.05) and negatively correlated with LVEF (r = -0.41, P < 0.01). Among the parameters, lnBNP level presented the largest AUC in their ROC curves (P < 0.01) for diagnosing decompensated heart failure and cardiogenic shock. The sensitivity, specifiticity and accuracy rates for diagnosing decompensated heart failure were 84.9%, 45.0% and 70.0% respectively by lnBNP at the cut point of 140 ng/L. The sensitivity, negative predicting value and accuracy rate for diagnosing cardiac shock were 82.8%, 66.7% and 67.4% respectively by BNP at the cut point of 400 ng/L. CONCLUSION: lnBNP level in hospitalized patients with AMI was positively correlated with Killip grades and LVEDd, negatively correlated with LVEF and could serve as a parameter for diagnosing the decompensated heart failure and excluding the cardiac shock.

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

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 = 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% (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% 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.