| B-type natriuretic peptide is mainly secreted from the cardiac ventricular in response to ventricular volume expansion and pressure overload quickly. Studies show that BNP can best diagnose heart dysfunction with higher sensitivity and specificity than other natriuretic peptides. But reports are less about its application to clinical practices. Objective:One purpose of this study was to explore the relation between blood B-type natriuretic peptide (BNP) concentration and severity of heart dysfunction, which is assessed by New York Heart Association (NYHA) functional classification, parameters of heart function examined by 2-D echocardiography and the distance of 6-minute walking test. The other purpose is to access the value of BNP in short-term prognosis in patients with heart failure. Methods:Eighty two outpatients or inpatients with heart dysfunction were enrolled, 44 men and 38 women, mean age (60.7+12.7 years), average left ventricular ejection fraction(0.44±0.12). Following parameters were measured: BNP from blood samples which acquired in two hours after admission or at out-patient department; Leftventricular (LV) ejection fraction (EF), LV fractional shortening (FS), LV end-diastolic diameter (LVEDD) from 2-D echocardiography; exercise performance from 6-minute walking test (6MWT, meters)(n=66). Blood BNP was measured using the Triage BNP test, which was a fluorescence immunoassay for quantification of the biologically active BNP-32 in whole blood or plasma samples. Patients with NYHA III -IV class(n=40) accepted treatment according to treatment guidline for heart failure for 2 to 26 days. Blood BNP was repeatedly measured during 24 hours before discharge or death. These patients were followed up for one month to investigate the major adverse clinical event, such as cardiac death, re-hospitalization for worsening heart failure. The value of BNP level in short-term prognosis in patients of heart failure was explored. Results:1. With increasing NYHA-class, BNP levels (mean±SD) increased: from 154.2±56.7pg/ml in patients with NYHA-class I to 461.3±149.1pg/ml in patients with NYHA-class II , 722.4±262.9pg/ml in patients with NYHA-class III , 1069.9±252.8pg/ml in patients with NYHA-class IV . There were significant differences between different classes (P<0.05).2. Significantly positive correlations were found between BNP and left ventricular end-diastolic diameter(r=0.592, P<0.01). Furthermore, there were significant inverse correlations between BNP and LVEF(r=-0.642, P<0.01), LVFS(r=-0.600, P<0.01). With increasing LVEDD and decreasing LVEF, BNP levels increased accordingly.3. Patients with NYHA I -III class (n=66) accepted 6MWT. There were significantly negative correlation between BNP level and physical performance(walking distance, meters) assessed by the 6MWT( r =-0.726, P<0.01). With increasing NYHA-class, the walking distance of 6MWT was decreased: from 525.9±79.3m in patients with NYHA-class I to 425.0+105.8m in patients with NYHA-class II, 314.2+ 127.6m in patients with NYHA-class III. There were significant differences between different Glasses (p<0.005).4. During one-month follow-up period, thirteen of the forty patients withNYHAIII-IV class exhibited a major adverse clinical event (MACE), such as cardiac death or re-hospitalization for deteriorating of heart function. Among them, three died during hospital (two died from heart failure, one died from sudden death) whose blood BNP levels greatly increased from 1416±872pg/ml to 3534±907pg/ml (p<0.01), averagely increased 2118pg/ml. Patents with MACE had significantly higher BNP level than those without MACE (1245.3 ± 435.2pg/ml vs. 932.3 ± 309.8pg/ml, P<0.05). After discharge, One patient died from sudden death, nine patients were re-hospitalized for worsening heart failure. Blood BNP concentration of patients without MACE during one month after discharge decreased under treatment(932. 3 + 309.8pg/ml vs. 459.1 ± 154.3pg/ml, P<0.001), averagely decreased 473pg/ml. However, Blood BNP concentration of patients with MACE during one month after discharge decreased slightly under treatment (1007.9 + 266.9pg/ml vs. 749.1 + 214.4pg/ml, P<0.01) and averagely decreased 258pg/ml. There are significant different between the changes of BNP lever. Patients with BNP lever higher than 500pg/ml had higher danger of MACE than those with BNP lever lower than 500pg/ml. There are significant different between the rate of MACE for those two groups (44.44% vs. 10.52%, p<0.05). Conclusion:l.Good correlation is found between BNP level and NYHA class, parameters of heart function measured by 2-D echocardiography and physical performance of the six minutes walking test. This study suggested that BNP has an important value in assessing the severity of heart dysfunction. It can be used to stratify the risk of heart failure.2.The change of BNP level under treatment for heart failure patients can reflect treatment-responsiveness. The increasing lever of BNP suggest higher rate of MACE and poor prognosis. Patients with BNP level decreased greatly have good prognosis than those with BNP level decreased slightly. BNP can be a predictor for short-term prognosis. |
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