Decreasing ratio of plasma N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide according to age.

BACKGROUND

B-type natriuretic peptide (BNP) and the N-terminal fragment of proBNP (NT-proBNP) seem to be useful diagnostic tools also in children with cardiac disease. Recent data suggest that plasma levels of both peptides show different patterns from infancy to adolescence.

AIM

To investigate the relationship of BNP and NT-proBNP in children and adolescents according to age.

SUBJECTS AND METHODS

In 46 individuals without cardiac disease (22 males, 24 females, aged 0.4-17.5 years) and 30 patients with congenital heart disease (17 males, 13 females, aged 0.2-18.4 years), plasma levels of BNP and NT-proBNP were measured in the same sample (triage BNP assay, Biosite and Elecsys NT-proBNP assay, Roche Diagnostics).

RESULTS

The range of BNP plasma levels was 5-32 pg/ml in individuals without heart disease and 5-1300 pg/ml in the patient group, the range of NT-proBNP was 10-298 pg/ml and 30-18,966 pg/ml, respectively. In both groups, the ratio NT-proBNP/BNP decreased with increasing age (P<0.001).

CONCLUSION

Although proBNP is cleaved into the two fragments NT-proBNP and BNP, there is a decreasing ratio of NT-proBNP/BNP with increasing age caused probably by age-dependent differences in the metabolic clearance of both peptides. This has to be considered in comparison studies on BNP and NT-proBNP regarding their benefit to paediatric cardiology.