title: Copeptin as a marker of relative arginine vasopressin deficiency after pediatric cardiac surgery.
abstract: OBJECTIVE
  Relative arginine vasopressin (AVP) deficiency after pediatric cardiac surgery has recently been described. Copeptin, a more stable and easily measured product of pro-AVP processing, may be a means of identifying these patients. We aimed to determine if copeptin was correlated with AVP in these children and whether it can be a surrogate marker of relative AVP deficiency.
  
  
  METHODS
  Patients <6 years of age with basic Aristotle scores ≥7 requiring surgery with cardiopulmonary bypass were prospectively enrolled. Plasma AVP and copeptin concentrations were measured pre-cardiopulmonary bypass and 4 and 24 h post-cardiopulmonary bypass. Relative AVP deficiency was defined a priori based on our previous work as AVP <9.2 pg/ml at 4 h post-cardiopulmonary bypass.
  
  
  RESULTS
  Of 41 children enrolled, relative AVP deficiency was present in 13 (32 %). AVP and copeptin concentrations were significantly lower in these 13 children at 4 h post-cardiopulmonary bypass as compared to the other 28 patients. A significant positive association between plasma AVP and copeptin concentrations over time was determined. Based on log-transformed analyses, a 1 % increase in plasma AVP led to a 0.19 % increase in copeptin. Further, copeptin <1.12 ng/ml at 4 h post-cardiopulmonary bypass had a sensitivity of 92 % and a negative predictive value of 95 % for relative AVP deficiency.
  
  
  CONCLUSIONS
  Plasma AVP and copeptin are positively associated in children undergoing cardiac surgery. Copeptin may represent a useful means of identifying relative AVP deficiency in these patients.
authors.affiliation: Department of Pediatrics, Wayne State University, Detroit, MI, USA. cmastrop@med.wayne.edu
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Mastropietro
authors.forename: Meredith
authors.initials: M
authors.lastname: Mahan
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Valentine
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Clark
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Hines
authors.forename: Henry L
authors.initials: HL
authors.lastname: Walters
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Delius
authors.forename: Ashok P
authors.initials: AP
authors.lastname: Sarnaik
authors.forename: Noreen F
authors.initials: NF
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D001127:Arginine Vasopressin / Q000172:deficiency* / Q000627:therapeutic use; D015415:Biomarkers; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006020:Glycopeptides / Q000097:blood*; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008297:Male; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D006020:Glycopeptides; C048197:copeptins; D001127:Arginine Vasopressin