To investigate the clinical value of serum brain natriuretic peptide (BNP) levels and N-terminal pronatriuretic peptide (NT-proBNP) levels in myocardial injury in neonates after asphyxia.

Subjects were selected from 106 neonatal asphyxia patients admitted to Department of Neonatology, according to the number organized in chronological order every other case. According to the diagnostic criteria of myocardial injury, these cases were divided into myocardial injury group (n=46) and non-cardiac injury group (n=60). The control group of 63 neonates was admitted in the same period without asphyxia or neonatal cardiovascular disease. Neonates with water and electrolyte balance disorders and kidney dysfunction were excluded from the controls. Blood sample was drawn from patients within 2 h of admission to hospital and again on day 14. The serum was prepared for the detection of serum BNP, creatine kinase isoenzyme (CK-MB), serum sodium and calcium.

Within 2 h after admission, the serum BNP level in the myocardial injury group was significantly higher than in the non-cardiac injury group (log transformed, respectively, P=0.030, P=0.001) and the control group (P=0.020). After treatment, serum BNP and NT-proBNP levels at 14th day after admission were decreased significantly compared to 2 h within admission (P=0.001). When the Cut-off value of BNP for children with myocardial injury was 108.05 pg/ml, the area under the receiver operating characteristic (ROC) curve was 0.754, with a sensitivity of 75.2%, a specificity of 64.6%, positive predictive value of 56.5% and negative predictive value of 72.4%. When the Cut-off value of NT-proBNP for children with myocardial injury was 3 615.5 pg/ml, the area under the ROC curve was 0.810, P=0.001, with a sensitivity of 83.4%, a specificity of 80.6%, positive predictive value of 82.9% and negative predictive value of 79.5%. Serum BNP and CK-MB levels were positively correlated in asphyxia patients (r=0.212, P=0.030). Serum NT-proBNP and CK-MB levels were positively correlated in asphyxia patients (r=0.406, P=0.007).

Serum BNP and NT-proBNP levels can reflect myocardial injury in neonates with asphyxia and can be used for early diagnosis of myocardial injury, but NT-proBNP level has a higher specificity and sensitivity.

Natriuretic peptide; Asphyxia neonatorum; Myocardial injury