The area under the ROC curve of serum NT-proBNP 3d postnatal diagnosis PDA is 0.949 (95% CI: 0.892 ~ 1.000, P <0.001), the critical value 6411pg / mL, sensitivity of 92.3% and a specificity of 92.9% (Fig.1). Here, NPPB is linked to Patent ductus arteriosus.