N-terminal pro-B-type natriuretic peptide: reference plasma levels from birth to adolescence. Elevated levels at birth and in infants and children with heart diseases

Aim: Determination of plasma levels of N-terminal pro-B-type natriuretic peptide (N-BNP) in infants and children with and without heart diseases. Methods: Plasma N-BNP was measured in 78 infants and children without heart disease and in 55 infants and children with heart disease causing volume and pressure overload. Heart diseases included chronic dilated cardiomyopathy, acute left ventricular dysfunction, and congenital cardiac anomalies resulting in left and right ventricular volume or pressure overload. The Mann-Whitney rank-sum test and the ANOVA for ranks test were used to compare two or more groups, respectively. Results: N-BNP levels were elevated in the first days of life but were not significantly different in children from 4 mo to 15 y old. The upper limit in children older than 4 mo with no heart disease was 349 pg/ml. In patients with heart disease, N-BNP levels were significantly higher than in control children ( p < 0.0001). Conclusion: N-BNP levels are elevated in the first days of life and are stable from age 4 mo to adolescence. Elevated N-BNP levels reflect cardiac dysfunction in infants and children.