title: Strong relationship between NT-proXNP levels and cardiac output following cardiac surgery in neonates and infants.
abstract: BACKGROUND
  NT-proXNP, a new natriuretic peptide analyte, incorporates information about the concentrations of both N-terminal pro-atrial and pro-brain natriuretic peptides (NT-proANP, NT-proBNP). We aimed to investigate whether NT-proXNP is a reliable indicator of the cardiac index (CI) and the hemodynamic state in neonates and infants undergoing an open heart surgery.
  
  
  METHODS
  We enrolled 26 children under the age of 1 year into this prospective study. All patients underwent an elective cardiac operation with cardiopulmonary bypass (CPB) to achieve complete biventricular repair. Peri-operative hemodynamic parameters were assessed by transpulmonary thermodilution and natriuretic peptide levels were recorded.
  
  
  RESULTS
  The NT-proXNP level correlated significantly with the simultaneously measured NT-proANP level (r=0.60, P<0.001), but more strongly with the NT-proBNP level (r=0.89, P<0.001) and the arithmetic sum of both (r=0.88, P<0.001). NT-proXNP had a strong correlation with CI (r=-0.85, P<0.001), the stroke volume index (r=-0.80, P<0.001) and the global ejection fraction (r=-0.67, P<0.009) throughout the post-operative period. Conventionally measured parameters such as heart rate, mean arterial pressure and pulse-pressure product exhibited weaker correlations with CI than NT-proXNP. Among laboratory values, creatinine levels correlated significantly with CI (r=-0.77, P<0.001) and NT-proXNP (r=0.76, P<0.001) during the post-operative period. A post-operative NT-proXNP level of 3079 pmol/l was diagnostic for CI <3 l/min/m(2) with 89% sensitivity and 90% specificity (area under the curve: 0.91 +/- 0.05).
  
  
  CONCLUSIONS
  NT-proXNP is a good marker of cardiac output following pediatric cardiac surgery and might be a useful tool in the recognition of a low output state.
authors.affiliation: Department of Pediatric Anesthesia and Intensive Care, Gottsegen György Hungarian Institute of Cardiology, Budapest, Hungary.
authors.forename: T
authors.initials: T
authors.lastname: Breuer
authors.forename: R
authors.initials: R
authors.lastname: Skoumal
authors.forename: F
authors.initials: F
authors.lastname: Horkay
authors.forename: B
authors.initials: B
authors.lastname: Merkely
authors.forename: M
authors.initials: M
authors.lastname: Ala-Kopsala
authors.forename: J
authors.initials: J
authors.lastname: Leppäluoto
authors.forename: O
authors.initials: O
authors.lastname: Vuolteenaho
authors.forename: H
authors.initials: H
authors.lastname: Ruskoaho
authors.forename: M
authors.initials: M
authors.lastname: Tóth
authors.forename: A
authors.initials: A
authors.lastname: Székely
mesh_terms: D015415:Biomarkers; D002302:Cardiac Output / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D003404:Creatinine / Q000097:blood; D004265:DNA Helicases / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006330:Heart Defects, Congenital / Q000601:surgery; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000601:surgery; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism*; D011184:Postoperative Period; D011446:Prospective Studies; D011498:Protein Precursors / Q000378:metabolism; D013318:Stroke Volume / Q000502:physiology; D013815:Thermodilution; D000075924:X-linked Nuclear Protein
chemical_list: D015415:Biomarkers; D009687:Nuclear Proteins; D011498:Protein Precursors; D003404:Creatinine; D004265:DNA Helicases; C092332:ATRX protein, human; D000075924:X-linked Nuclear Protein