title: Antithrombin concentrate in pediatric patients requiring unfractionated heparin anticoagulation: a retrospective cohort study.
abstract: OBJECTIVE
  To describe antithrombin levels, altered unfractionated heparin effect (anti-factor Xa activity and activated partial thromboplastin time), and adverse effects post administration of a single high dose of antithrombin concentrate.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  Infants and children with antithrombin levels less than 50% and a subtherapeutic unfractionated heparin effect.
  
  
  METHODS
  Quaternary care children's hospital with a dedicated anticoagulation program.
  
  
  METHODS
  None.
  
  
  RESULTS
  A single high dose of antithrombin concentrate was administered. Antithrombin level, anti-factor Xa, and activated partial thromboplastin times were measured post antithrombin concentrate infusion and daily until stable. One hundred twenty-one patients received 246 doses of antithrombin. Patients were described using two cohorts based on the ability to obtain exact heparin doses. Cohort 1 included all patients between January 2004 and May 2008 when complete heparin dosing was unavailable. Cohort 2 included patients from May 2008 to May 2011 when heparin dose was available. Median age and weight were 3.7 months and 4.1 kg. Mean antithrombin concentrate dose was 222 IU/kg. Mean antithrombin level increased from 0.39 to 1.20 U/mL following antithrombin concentrate administration. In cohort 2, unfractionated heparin doses to achieve a target anti-factor Xa activity pre-post antithrombin concentrate were 28 and 19 U/kg/hr, respectively, for children 12 months old or younger and 25 and 19 U/kg/hr, respectively, for children older than 12 months. There were no hemorrhagic, thrombotic, or allergic events within 1 week of antithrombin concentrate administration.
  
  
  CONCLUSIONS
  This is the largest study of antithrombin concentrate evaluation in children. Administration of antithrombin concentrate increases anti-factor Xa activity with lower administered unfractionated heparin doses.
authors.affiliation: 1Pediatric Critical Care, Stollery Children Hospital, University of Alberta, Edmonton, AB, Canada. 2Pediatric Cardiology-Thrombosis, Stollery Children's Hospital, University of Alberta, Edmonton, AB, Canada. 3Departments of Pediatrics and Obstetrics and Gynaecology, Dalhousie University, Halifax, NS, Canada. 4Department of Hematology, Stollery Children's Hospital, University of Alberta, Edmonton, AB, Canada. 5Pediatric Cardiology-Thrombosis, Stollery Children's Hospital, Edmonton, AB, Canada.
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Ryerson
authors.forename: Mary E
authors.initials: ME
authors.lastname: Bauman
authors.forename: Stefan
authors.initials: S
authors.lastname: Kuhle
authors.forename: Aisha A
authors.initials: AA
authors.lastname: Bruce
authors.forename: M Patricia
authors.initials: MP
authors.lastname: Massicotte
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D000991:Antithrombins / Q000097:blood*; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D065427:Factor Xa Inhibitors / Q000097:blood*; D005260:Female; D006493:Heparin / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010314:Partial Thromboplastin Time; D012189:Retrospective Studies
chemical_list: D000925:Anticoagulants; D000991:Antithrombins; D065427:Factor Xa Inhibitors; D006493:Heparin