Performance of urinary NT-proBNP in ambulatory settings

Background: NT-proBNP (N-terminal prohormone of brain natriuretic peptide) has been established as a useful biomarker in plasma for children with congenital heart disease (CHD). Plasma values were shown to correlate well with urinary values. We designed a study to investigate the general utility of urinary NT-proBNP in children with and without CHD in an ambulatory setting. Material and methods: 202 children (mean age 93 months (1-225 months)) were included in the analysis. We investigated the performance of urinary NT-proBNP values determined from spot urine as a diagnostic tool for different forms of congenital heart disease. Results: Urinary NT-proBNP is a good diagnostic tool for children with congenital heart disease (ROC area under the curve 0.807). Combining these values with the Ross-classification further improves the diagnostic power (ROC area under the curve 0.831) Analysis also showed significant differences between Lg(10) urinary NT-proBNP values of healthy controls and those of children after corrective surgery. Furthermore, children who have completed the stages of Fontan palliation showed higher values than age matched controls. Conclusions: Urinary NT-proBNP can be used in an ambulatory setting to discriminate between relevant and nonrelevant CHD and might be valuable as a follow up parameter for children after biventricular repair or univentricular palliation. Age dependant urinary NT-proBNP normal values for children could be an easy-to-use tool for general practitioners as well as specialised clinics.