Clinical Study Of The Relationship Between Blood B-type Natriuretic Peptide Level And Heart Dysfunction

B-type natriuretic peptide (BNP) is a neurohormone mainly secreted by ventricular myocytes. Increase of ventricular burden and wall tension can stimulate release of BNP. BNP level can reflect the severity of left and right ventricular dysfunction. A randomized clinical trial abroad demonstrated that BNP test can be used to diagnosis the heart failure, and it's sensitivity and specificity is higher than the other natriuretic peptides. Up to now, clinical studies about the relationship of BNP level and severity of heart dysfunction are lacking in our country.OBJECTIVES1. To evaluate the value of BNP in diagnosis of heart failure.2. To evaluate the value of BNP in prognosis of patients with heart failure by studying the correlation between blood BNP level and severity of heart dysfunction which was assessed by New York Heart Association(NYHA) functional classification, and cardiothoracic ratio (CTR).METHODS1. 97 patients with acute dyspnea were enrolled, 58 men and 39 women. According to case history, symptom, physical examination and auxiliary examination, the patients were divided into two groups: group A (dyspnea caused by heart dysfunction , 65 patients) and group B (dyspnea not caused by heart dysfunction, 32 patients). Blood BNP was measured by fluorescence immunoassay within 2 hours after admission or at out-patient department; left ventricular ejection fraction (LVEF) were measured by echocardiography; cardiothoracic ratio (CTR) were measured by chest film.2. 65 patients in group A were divided into three groups by NYHAII -IV, then accepted treatment according to guidline for heart failure. Blood BNP, LVEF and CTR were measured before treat, one month after treat and three months after treat, to evaluate the value of BNP level in short-term prognosis in patients of heart failure.RESULTS1. BNP levels in group A and group B were 692.48±339.18ng/l and 67.29±16.41 ng/l respectively. Compared with group B, BNP levels in group A increased significantly (P<0.05).2. There were difference between NYHA-class II, NYHA-class III and NYHA-class IV(P<0.05), BNP levels were 225.34±68.53 ng/l, 578.45±108.98 ng/l and 1093.67±233.65 ng/l in patients with NYHA-classII, III and IV.3. BNP level significantly inverse correlations with LVEF in group A (r=-0.610, p<0.05).4. In group A, 3 patients died during hospital, 62 patients relieved. During three-month follow-up period, BNP levels, LVEF and CTR were observed , Blood BNP concentration decreased from 692.48±339.18ng/l to 489.23±102.56 ng/l in one month and 236.34±27.84 ng/l in three months (p<0.05).CONCLUSIONS1. Blood BNP is useful index in diagnosis of heart dysfunction in acute dyspnea.2. Good correlation was found between BNP level and NYHA class, parameters of heart function, cardiothoracic ratio. This study suggested that BNP played an important role in assessing the severity of heart dysfunction.3. The change of blood BNP level after treatment can reflect treatment-responsiveness in heart failure patients, increase of BNP level suggested poor prognosis. Patients with BNP level decreased greatly had good prognosis than those with BNP level decreased slightly. BNP can be a predictor for short-term prognosis.