Urinary NT-proBNP and ductal closure in preterm infants

Objective:to explore the association of urinary n-terminal pro-brain natriuretic peptide (nt-probnp) concentrations and closure of patent ductus arteriosus (pda) in preterm infants.study design:blinded prospective study involving 136 preterm infants (median (interquartile range) gestational age 28 (26 to 30) weeks; birth weight 1030 (780 to 1270) g). nt-probnp was determined in urine collected on day of life (dol) 2, 7, 14 and 28.result:urinary nt-probnp/creatinine ratios declined continuously between dol 2 (74 (17 to 248) μg g−1) and dol 28 (4 (2 to 12) μg g−1) and were significantly elevated in ventilated infants on dol 2, 7 and 14, and in ventilated infants with a hemodynamically significant pda on dol 2. furthermore, urinary nt-probnp/creatinine ratios on day 14 were higher in 14 ventilated infants who did not respond to pharmacological treatment and subsequently required surgical pda closure (247 (214 to 547) μg g−1) than in ventilated infants (n=7) with successful pharmacological pda closure (55 (21 to 114) μg g−1; p<0.05). a cutoff >210 μg g−1 on day 14 had a sensitivity of 75% and specificity of 100% for predicting non-responsiveness to pharmacological treatment.conclusion:measurement of urinary nt-probnp is a new and simple non-invasive test for preterm infants, which may be helpful in guiding pda treatment decisions.