INTRODUCTION: N-terminal pro–brain natriuretic peptide (NT-proBNP) in adults has been reported to be a diagnostic marker of ventricular enlargement and volume overload. However, clinical studies using NT-proBNP in premature infants have been very limited.
OBJECTIVE: We sought to determine whether plasma NT-proBNP in premature infants can identify hemodynamically significant patent ductus arteriosus (hsPDA) and determine the correlation between serial plasma NT-proBNP level and echocardiographic assessment of PDA.
METHODS: Thirty-nine preterm infants underwent clinical and echocardiographic examinations for PDA on days-of-life 2, 4, and 7 and simultaneous blood sampling to measure plasma NT-proBNP concentrations. When ≥2 clinical features of PDA were detected along with left-to-right ductal shunting demonstrated by echocardiogram, hsPDA was diagnosed and the patient treated with indomethacin or ibuprofen.
RESULTS: On day 2, the mean NT-proBNP concentration in the hsPDA group (n = 12) was significantly higher than that in the non-hsPDA group (n = 23) (3160.3 ± 3104.9 vs 618.1 ± 490.7 pmol/L; P ≤ .05). Eight infants (72%) in the hsPDA group became asymptomatic after an initial course of indomethacin or ibuprofen, and their NT-proBNP levels concomitantly declined. NT-proBNP concentrations were significantly correlated with the magnitudes of the ductal shunt, such as left-atrium/aorta ratio and left-atrium volume index (r = 0.753 and 0.596, respectively). The cutoff of NT-proBNP concentration at 1204 pmol/L on day 2 gave the best predictive values for hsPDA with 100% sensitivity, 91% specificity, 86.7% positive predictive value, 100% negative predictive value, and a likelihood ratio of 11.5.
CONCLUSIONS: The plasma NT-proBNP level on day-of-life 2 is a sensitive marker for predicting hsPDA in preterm infants. Successful closure of PDA corresponds with a decline in plasma levels of NT-proBNP.