Abstract: Objective: To explore the change in the cerebral natriuretic peptide (BNP) levels in the premature infants with hemodynamically significant patent dectus arteriosus (hsPDA) and its relationship with hemodynamics, and to further clarify the clinical significance of BNP in the judgement of illness condition and treatment in the premature infants with hsPDA.Methods: A total of 106 cases of premature infants within 6 h of birth whose gestational age was no more than 32 weeks were selected and divided into hsPDA group (43 cases) and PDA with no hemodynamic significance group (nhsPDA group, 27 cases) and no PDA group (nPDA group, 36 cases).The patients in HsPDA group were divided into hsPDA treatment group(33 cases) and hsPDA non-treatment group(10 cases) according to whether ibuprofen was administrated or not. Echocardiography was performed in the patients in hsPDA treatment group,7 d after oral ibuprofen administration, and the patients in hsPDA treatment group were divided into hsPDA close group(15 cases) and hsPDA non-close group(18cases). The left atrium (LA)/aortic root diameter (VO) value, diameter of patent arterial duct, left ventricular ejection fraction(LVEF), shortening fraction, left ventricular end-diastolic diameter(LVEDD) and left ventricular end-systolic diameter(LVESD) were recorded at 1, 3, 7 d after birth of the premature infants in various groups with echocardiography.The level of BNP in plasma was determined by electrochemiluminescence. The correlation analysis was performed between the hemodynamic indexes of echocardiography and the level of BNP in plasma.Results: Compared with nhsPDA group, the LA/VO value, arterial catheter diameter and LVEDD were significantly increased (P<0.05).The plasma BNP levels of premature infants in hsPDA close and non-close groups at 1 and 3 d after birth were significantly higher than those in nPDA group (P<0.05); the plasma BNP level of the premature infants in hsPDA close group at 7 d after birth was significantly lower than that at 3 d after birth (P<0.05).Compared with hsPDA non-treatment group, the LA/VO value, arterial catheter diameter,LEVDD and the plasma BNP level of the premature infants in hsPDA treatment group at 7 d after birth were significantly decreased (P<0.05). The plasma BNP level was positively correlated with the LA/VO value and arterial catheter diameter (r=0.727,P<0.05;r=0.780, P<0.05) of the premature infants in hsPDA group at 3 d after birth.Conclusion: The level of plasma BNP of premature infants 3 d after birth is positively correlated with the hemodynamic indexes, and the detection of the changes of the plasma BNP levels is helpful to judge the condition of preterm infants with hsPDA and to provide basis for its diagnosis.

Key words: hemodynamics, patent ductus arteriosus, premature infant, brain natriuretic peptide