Change In Early-stage Plasma Nt-probnp Level In Preterm Infants With Patent Ductus Arteriosus And Its Clinical Significance

Objective By analyzing the change of plasma NT-pro BNP level in preterm infants with patent ductus arteriosus(PDA) in their 1st week and its correlation with hemodynamics indexes obtained by ultrasonography, this study aims to explore the clinical application value of plasma NT-pro BNP for diagnosis and treatment of preterm infants with s PDA.Methods We recruited 107 preterm infants with gestational age of 28-32 weeks and birth weight less than 1500 g admitted to the neonatal intensive care unit(NICU) of the First People’s Hospital Hospital from October 2013 to September 2014. All the infants were divided into the PDA group(n=39) and the control group(n=68); infants in the PDA group were classified into the s PDA group and the as PDA group according to whether there were clinical symptoms and significant hemodynamics changes by using ultrasonography on the 4th day of life; the s PDA group was divided into two groups in the light of whether there was drug contraindication, and the treatment group received ibuprofen; according to whether there was complication of BPD, infants were divided into the BPD group and the non-BPD group. Peripheral venous blood of all objects was respectively collected on the 1st, 4th and 7th day of life, and the plasma NT-pro BNP concentrations were determined by using an enzyme immunoassay; echocardiography examination was performed within 30 minutes after collection of blood. Statistical analysis was done to compare the plasma concentration of NT-pro BNP in the different groups and at different time points in the same group, and the correlation between plasma NT-pro BNP levels and hemodynamics indexes was analyzed. Receiver operating characteristic(ROC) curve was generated to select the best cut-off point for detection of s PDA.Results(1)Plasma concentration of NT-pro BNP of s PDA group was higher than that of the control group on the 1st, 4th and 7th day after birth and the as PDA group on the 4th and 7th day after birth(P<0.05); infants in the as PDA group had higher plasma NT-pro BNP levels than those in control group on the 4th day of life(P<0.05).(2)In the control group, the plasma concentration of NT-pro BNP was highest on the 1st day and then progressively declined during day 4-7 after birth, the difference was statistically significant(P<0.05); plasma NT-pro BNP concentrations on the 1st and 4th day after birth of infants in the as PDA group were higher than those on the 7th day after birth(P<0.05); in the s PDA group, plasma level of NT-pro BNP was found to peak on the 4th day after birth, which was obviously higher than that on the 1st and 7th day after birth(P<0.05).(3)Plasma NT-pro BNP levels on day 7 after birth of infants in the treatment group was significantly decreased compared to those on the 4th day after birth(P<0.05); there was no significant difference of the plasma level of NT-pro BNP in the non-treatment group on the 4th and 7th day after birth(P>0.05).(4)The plasma NT-pro BNP concentrations on the 4th day after birth showed significant positive correlation with DA diameter, LA/AO and TDD/LPA(r=0.670、0.498、0.529, respectively; P<0.05) but no correlation with EF and FS(P>0.05).(5)The prevalence of BPD in the s PDA group was 76.47%, which was higher than that in the as PDA group(35.29%), the difference was statistically significant(P<0.05).(6)Infants in the BPD group had higher plasma NT-pro BNP levels than those in the non-BPD group on the 4th and 7th day after birth; there was significant difference between the two groups regarding plasma NT-pro BNP levels on the 4th day after birth(P<0.05), but no statistical difference was observed between the two groups on the 7th day(P>0.05).(7)Area under receiver operating characteristic(ROC) curve for detection of s PDA was 0.969(95%CI 0.938 to 1.000;likelihood ratio 20.66). A cut-off NT-pro BNP on day 4 of 13964pg/ml offered the best predictive values for s PDA with a sensitivity of 95%, specificity of 95.4% and negative predictive value was 98.8%.Conclusions(1)Plasma NT-pro BNP concentrations of as PDA group infants were declined during the first week of life; in the s PDA group, Plasma concentration of NT-pro BNP was found to peak on the 4th day after birth, and was higher than that of as PDA group, but significantly decreased after treatment with ibuprofen.(2)Plasma concentration of NT-pro BNP was closely correlated to DA diameter, LA/AO and TDD/LPA.(3)The higher early-stage plasma NT-pro BNP level of preterm infants with PDA was, the more likely it was to develop BPD.(4)Plasma NT-pro BNP level on day 4 are capable of prediction of s PDA in preterm infants, which may provide a basis for trials of targeted medical treatment.