N-terminal probrain natriuretic peptide and patent ductus arteriosus in preterm infants

Objective: To determine whether plasma N-terminal probrain natriuretic peptide (NT-proBNP) in premature infants could identify hemodynamically significant patent ductus arteriosus (HsPDA) and to determine the correlation between serial plasma NT-proBNP and echocardiographic assessment of ductal shunting. Study Design: An observational study involving 35 preterm infants who underwent echocardiographic assessment for PDA on day 2, 4 and 7 of life with simultaneous blood sampling for determination of NT-proBNP concentrations. HsPDA was diagnosed by left-to-right ductal shunt on color Doppler, measuring diameter >1.5 mm on two-dimensional echocardiography plus ≤2 clinical features of PDA. Result: Plasma NT-proNBP levels on day 2 in the HsPDA group (n=12) were significantly higher than in non-HsPDA group (n=23) with a median of 16353 pgml^-1 (interquartile range (IQR), 12360-33459; range, 10316-104998) vs 3914 pgml^-1 (IQR, 2601-5782; range, 1535-19516) (P<0.001), respectively. Eight infants (67%) in the HsPDA group responded to an initial course of indomethacin or ibuprofen and their NT-proBNP levels significantly decreased within 48h after treatment compared with non-responders (P=0.007). NT-proBNP concentrations were significantly correlated with left atrial to aortic root ratio. A cut-off NT-proBNP on day 2 of 10180 pgml^-1 offered the best predictive values for HsPDA with a sensitivity of 100% and a specificity of 91%. Conclusion: Plasma NT-proBNP on day 2 was found as a sensitive marker for predicting HsPDA in preterm infants. Successful closure of PDA was also correspondent with the decline in plasma NT-proBNP.