Diagnostic role of plasma BNP levels in neonates with signs of congenital heart disease

Abstract

Background: Only a few studies have examined the relationship of plasma BNP levels and congenital heart disease (CHD) in neonates and these mainly concern preterm neonates with patent ductus arteriosus. We aimed to investigate the diagnostic role of plasma BNP in neonates admitted in the neonatal intensive care unit, (NICU), with signs of congenital heart disease (CHD).

Methods: Prospective assessment of plasma BNP levels in 75 consecutive neonates with suspected CHD (heart murmur, respiratory distress, or cyanosis), admitted in the NICU of our university hospital. The final diagnosis was done with echocardiography.

Results: Haemodynamically significant Left to Right shunts, (hsLtR), were found in 29 neonates, insignificant LtR shunts in 22, no heart disease in 15 and cyanotic heart disease in 9. BNP levels were significantly higher in neonates with hsLtR shunts vs. all other groups (logBNP 2.9 ± 0.5 pg/ml vs. 1.5 ± 0.4 pg/ml vs. 1.5 ± 0.3 pg/ml vs. 1.6 ± 0.2 pg/ml, p < 0.0001). Plasma BNP levels > 132.5 pg/ml had 93.1% sensitivity and 100% specificity for diagnosing hsLtR shunts (accuracy 99.6%).

Conclusions: Plasma BNP is a reliable test for diagnosing hsLtR shunts in the NICU. This will alert the neonatologist for ordering an echocardiographic examination, or if the latter is not available, for transferring the neonate to an appropriate tertiary centre with neonatal-paediatric cardiology facilities. Normal BNP levels imply the absence of a significant LtR shunt, but may not exclude cyanotic heart disease.