Background: The plasma concentrations of brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) can reflect cardiac function and therefore can be used for the diagnosis of congestive heart failure (CHF) and the evaluation of cardiac function. However, few studies focused on BNP and NT-proBNP in pediatric patients with congenital heart defects. The aim of this study was to assess the value of NT-proBNP in the diagnosis of patients with ventricular septal defect (VSD) and congestive heart failure.

Methods: Fifty-one children with VSD aged from 2 months to 2 years (mean 7.9 months) were enrolled in this study. According to the modified Ross Score, they were divided into 3 groups: 20 patients without CHF (score 0-2), 18 patients with mild CHF (score 3-6), and 13 patients with moderate to severe CHF (score 7-12). A group of 15 age-matched healthy children served as controls. The levels of plasma NT-proBNP were determined with an enzyme immunoassay. All participants were subjected to complete echocardiographic examination for measuring left ventricular end diastolic volume index (LVEDVI), left ventricular end systolic wall stress (LVESWS), heart rate-corrected mean velocity of circumferential fibre shortening (mVcFc), left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), and contractility index (Con). The correlation of plasma NT-proBNP with the modified Ross Score and functional indices measured echocardiographically was analyzed. The sensitivity, specificity and the receiver operating characteristic (ROC) curve for NT-proBNP as a diagnostic marker of CHF were calculated.

Results: The levels of plasma NT-proBNP were positively correlated with the modified Ross Score (r=0.75, P<0.01). The levels were significantly higher in patients with moderate to severe CHF (2061±908 fmol/ml) than in those with mild CHF (810±335 fmol/ml), but in the latter the levels were significantly higher than in patients without CHF (309±68 fmol/ml). In 97% of the patients without CHF and healthy controls, the plasma levels were below 400 fmol/ml. In 83% of the patients with mild CHF, the levels ranged from 400 to 1400 fmol/ml, whereas in 85% of the patients with moderate to severe CHF the levels of plasma NT-proBNP were above 1400 fmol/ml. Plasma NT-proBNP was positively correlated with LVEDVI and LVESWS, but it was not correlated with mVcFc, LVEF, LVFS and Con. When plasma NT-proBNP ≥400 fmol/ml was used as cut-off point for diagnosing CHF, the sensitivity was 89.3%, the specificity was 91.2%, and the area under the ROC curve was 0.944.

Conclusion: Plasma NT-proBNP can be used to evaluate cardiac function and diagnose CHF in pediatric patients with VSD.