Role of brain-type natriuretic peptide in rapid diagnosis and prognosis of persistent pulmonary hypertension of the newborn

Abstract

Objective The diagnosis of persistent pulmonary hypertension of the newborn (PPHN) can often be difficult to make, especially in a clinical setting in which pediatric echocardiography is not readily available. This study aims at investigating the value of plasma brain-type natriuretic peptide (BNP) level as a noninvasive test in the diagnosis, prognosis, and differentiation of PPHN from other respiratory diseases in newborns with respiratory distress (RD). Patients and methods We used a prospective cohort study with three groups. One group was diagnosed with PPHN by clinical and echocardiographic criteria (PPHN group: n=20). The second group had been diagnosed with respiratory disease; however, PPHN was ruled out by having no evidence of elevated pulmonary pressure by echocardiography (RD group: n=20). The third group had no respiratory disease and was breathing room air (RA group: n=20). Plasma BNP levels were measured by Ray Bio BNP Enzyme Immunoassay Kit at study entry for all groups and upon recovery for PPHN cases. Results There was no difference between groups regarding gestational age, postnatal age, sex, birth weight, and mode of delivery. Initial BNP levels (pg/ml) were significantly elevated in the PPHN group relative to both the RA and RD groups. There was no difference in the initial plasma BNP level between the RD and RA groups. Plasma BNP levels declined significantly in the PPHN group upon recovery. Plasma BNP levels correlated with the gradient of the tricuspid regurgitation jet and the mean pulmonary artery pressure. Plasma BNP levels were higher, although insignificant, in PPHN because of underdevelopment. The mean plasma BNP level in septic babies was higher; however, this was insignificant, still the number of cases was low (two cases). Conclusion Plasma BNP levels were elevated in infants with PPHN but not in infants with other forms of RD. Follow-up plasma BNP level showed significant decline after recovery of PPHN cases. Elevated plasma BNP levels in term or near-term infants with RD should increase the suspicion of PPHN.