title: Correlation of B-type natriuretic peptide levels and echocardiographic parameters in preterm infants with patent ductus arteriosus.
abstract: OBJECTIVE
  This study aimed to evaluate the correlation, according to postnatal age, between plasma B-type natriuretic peptide (BNP) levels and echocardiographic parameters for the assessment of patent ductus arteriosus (PDA) in preterm infants with respiratory distress.
  
  
  METHODS
  We enrolled 42 preterm infants with respiratory distress who underwent serial echocardiographic evaluation with simultaneous plasma BNP measurements until ductal closure. The correlations between BNP levels and the following 4 representative echocardiographic parameters were studied: diameter of the ductus arteriosus (DA), ratio of the left atrial diameter to the aortic diameter (LA/Ao), ratio of the PDA diameter to the infant's left pulmonary artery diameter (PDA/LPA), and the antegrade diastolic flow of LPA (DFLPA).
  
  
  RESULTS
  BNP levels were significantly correlated to the magnitude of the ductal shunt, comprising the DA diameter, PDA/LPA ratio, LA/Ao ratio, and antegrade DFLPA for the overall study period. The earliest significant correlation, starting from postnatal day 2, was observed between the LA/Ao ratio and BNP levels. The PDA/LPA ratio and the antegrade DFLPA showed significant correlations with BNP levels postnatal day 3 onward, and with the DA diameter, postnatal day 5 onward.
  
  
  CONCLUSIONS
  BNP levels and echocardiographic parameters showed a positive correlation, but the significance of the correlations differed according to the postnatal age, especially during the first few days of life.
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hyun Ah
authors.initials: HA
authors.lastname: Jeong
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Jeonghee
authors.initials: J
authors.lastname: Shin
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Eunji
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Byung Min
authors.initials: BM
authors.lastname: Choi
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Chang Sung
authors.initials: CS
authors.lastname: Son
authors.affiliation: Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.
authors.forename: Joo Won
authors.initials: JW
authors.lastname: Lee
keywords: B-type natriuretic peptide; Echocardiography; Patent ductus arteriosus; Premature infant