B-type natriuretic peptide: prognostic marker in congenital diaphragmatic hernia.

BACKGROUND: B-type natriuretic peptide (BNP) has not been evaluated in newborns with congenital diaphragmatic hernia (CDH). We hypothesized that BNP and severity of pulmonary hypertension (PH) would predict clinical outcome in these infants.

METHODS: We measured BNP levels and assessed severity of PH by echocardiography at 1 d and 1 wk of life. Outcome was classified by status at 56 d (or prior discharge): Good (n = 13) if alive on room air and Poor (n = 14) if expired or receiving respiratory support. We estimated area under the curve (AUC) and 95% confidence interval (CI).

RESULTS: BNP levels were higher at 1 d in newborns with Poor outcome (median 220 pg/ml vs. 55 pg/ml, P < 0.01). At 1 wk, there was no significant difference in BNP level (median 547 pg/ml vs. 364 pg/ml, P = 0.70, for Poor and Good outcomes). At 1 d, BNP level predicted outcome (AUC = 0.91, 95% CI = 0.77-1.0), but this relationship dissipated by 1 wk (AUC = 0.55, 95% CI = 0.31-0.79). Severity of PH did not predict outcome at 1 d (AUC = 0.51, 95% CI = 0.27-0.74), but prediction improved at 1 wk (AUC = 0.80, 95% CI = 0.61-0.99).

CONCLUSION: BNP is a strong predictor of clinical outcome in newborns with CDH at 1 d of life.