Usefulness of B-type Natriuretic Peptide Assay in Predicting Symptomatic Patent Ductus Arteriosus in Preterm Infants

PURPOSE: Earlier and accurate identification of preterm infants who are likely to develop hemodynamically significant patent ductus arteriosus (hsPDA) would allow for early prophylaxis and thus minimize the risk of neurologic and respiratory morbidity. The purpose of this study is to clarify the usefulness of plasma B-type natriuretic peptide (BNP) as an early biochemical predictive marker of subsequent symptomatic PDA (sPDA) in preterm infants. METHODS: Clinical and echocardiographic findings of PDA were evaluated at 24 and 48 hours of age in 69 infants ranging from 25 to 34 gestational weeks of age. Plasma BNP concentrations were simultaneously measured with a Triage(R) BNP test kit (Biosite Diagnositics, San Diego, California, U.S.A.). When two or more clinical symptoms of PDA and large ductal shunt from echocardiographic findings were found, sPDA was diagnosed and treated with indomethacin. RESULTS: The mean BNP level in sPDA group (N=22) was significantly higher than that of control group (N=47) at 24 and 48 hours. BNP levels were significantly correlated with the magnitudes of the ductal shunt, such as the ratio of left atrial to aortic root diameter and the diastolic flow velocity of the left pulmonary artery. At 24 hours of age, a cutoff BNP value of 468.5 pg/mL had a sensitivity of 90.9%, a specificity of 74.5% and a positive predictive value of 95.2% for prediction of sPDA (area under ROC curve: 0.908, P<0.001, 95% CI: 0.840 to 0.977). CONCLUSION: Rapid BNP assay allows early prediction of subsequent sPDA that may require treatment in preterm infants.

Reliability of Diastolic Flow Velocity of the Left Pulmonary Artery for the Diagnosis of Patent Ductus Arteriosus in Preterm Infants

PURPOSE: Diagnosis of a hemodynamically significant patent ductus arteriosus (PDA) that should be treated is difficult to determine by clinical and echocardiographic examination. The purpose of this study is to clarify the usefulness of diastolic flow velocity (DFV) of the left pulmonary artery (LPA) determined by echocardiography in the assessment of significant PDA in preterm infants. METHODS: Clinical and echocardiographic findings, including DFV in LPA, of PDA were evaluated at 24 hours, 48-72 hours of age and after indomethacin treatment in thirty-nine infants ranging from 25 to 34 gestational weeks of age. DFVs of the study group (N=13) with significant PDA were compared with those of healthy control group (N=26) without significant PDA. RESULTS: DFVs in healthy preterm infants were high in the first few days and were significantly decreased after spontaneous ductal closure. DFVs in preterm infants with significant PDA who underwent indomethacin treatment were significantly higher than that of healthy control infants. After indomethacin treatment, DFVs in this study group remained high with continuing significant PDA and markedly decreased with disappearance of significant PDA. Until ductus arteriosus closed, DFVs showed a significant correlation with the magnitudes of ductal shunt. A cutoff value for DFV of 30 cm/sec showed a sensitivity of 77% and a specificity of 92% as a predictor of significnat PDA in preterm infants. CONCLUSION: Measurement of DFV in LPA by echocardiography is a useful method for assessing the significnat PDA which may require treatment in preterm infants.