Plasma levels of natriuretic peptides and hemodynamic assessment of patentductus arteriosus in preterm infants

The main purpose of this study was to investigate whether circulating natri uretic peptides in premature infants reflect the hemodynamic significance o f a patent ductus arteriosus (PDA). The study comprises 120 examinations in 55 premature infants with a mean gestational age of 27.2 wk and a mean bir thweight of 933 g. Based on clinical and echocardiographic findings, the he modynamic influence of ductal shunting was classified as small, moderate or large. Blood samples for N-terminal proatrial natriuretic peptide (Nt-proA NP) and brain natriuretic peptide (BNP) were analysed after completion of t he clinical part of the study. Linear regression indicated a very strong as sociation between Nt-proANP and BNP (adjusted R-2 = 0.89). The mean levels of Nt-proANP and BNP increased with the size of the shunt through a PDA, an d peptide values followed hemodynamic alterations. The size of PDA accounte d for 50% and 47% of the total variation in the plasma values of Nt-proANP and BNP, respectively. In detecting an echocardiographically significant PD A, the area under a ROC curve was 0.94 for Nt-proANP and 0.90 for BNP. Conclusion: The magnitude of shunting through a PDA is the main determinant of plasma levels of natriuretic peptides in premature infants. Nt-proANP a nd BNP seem to have the same pattern of secretion. Our findings indicate th at measurements of natriuretic peptides may provide clinically relevant inf ormation in the hemodynamic assessment of premature infants.