title: Antithrombin Concentrate Use in Children Receiving Unfractionated Heparin for Acute Thrombosis.
abstract: OBJECTIVE
  To characterize features of antithrombin concentrate (ATC) use in children receiving unfractionated heparin (UFH) therapy for acute thrombosis.
  
  
  METHODS
  All pediatric patients at Texas Children's Hospital who received ATC in the context of UFH therapy for acute thrombosis during February 2011 to May 2013 were analyzed.
  
  
  RESULTS
  Fifty-one children received ATC during UFH therapy for acute thrombosis. Median age was 3 months (IQR 1 to 18 months). Clinical indications included venous (53%), arterial (37%), venous and arterial (6%), and intracardiac (4%) thrombosis. Median baseline antithrombin (AT) level was 61% and UFH dose was 26 U/kg/h. The median dose of ATC was 49.9 IU/kg (IQR 32.6 to 50.0 IU/kg). Although most patients (86%) did not undergo a change in UFH dose, there was a significant increase in both AT and anti-factor Xa level after the first dose of ATC (P < .001 for both). There was no correlation between ATC dose or increment in AT level above baseline and the achievement of targeted anticoagulation by anti-factor X activity level. Adverse bleeding events occurred in 10% of patients.
  
  
  CONCLUSIONS
  There was a significant change in AT and anti-factor Xa activity level after a single dose of ATC despite little to no change in dose of UFH. ATC appears to facilitate anticoagulation with UFH in some children with acute thrombosis but the degree of response is variable and dependent on factors identified in this study. Bleeding and other theoretical risks must be carefully considered.
authors.affiliation: Texas Children's Hospital, Houston, TX. Electronic address: Rxdiaz@txch.org.
authors.forename: Rosa
authors.initials: R
authors.lastname: Diaz
authors.affiliation: Texas Children's Hospital, Houston, TX.
authors.forename: Brady S
authors.initials: BS
authors.lastname: Moffett
authors.affiliation: Texas Children's Hospital, Houston, TX.
authors.forename: Shaina
authors.initials: S
authors.lastname: Karabinas
authors.affiliation: Baylor College of Medicine, Houston, TX.
authors.forename: Danielle
authors.initials: D
authors.lastname: Guffrey
authors.affiliation: Texas Children's Hospital, Houston, TX.
authors.forename: Donald H
authors.initials: DH
authors.lastname: Mahoney
authors.affiliation: Texas Children's Hospital, Houston, TX.
authors.forename: Donald L
authors.initials: DL
authors.lastname: Yee
mesh_terms: D000208:Acute Disease; D000925:Anticoagulants / Q000627:therapeutic use*; D000990:Antithrombin III / Q000627:therapeutic use*; D000991:Antithrombins / Q000097:blood; D004305:Dose-Response Relationship, Drug; D065427:Factor Xa Inhibitors / Q000097:blood; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010314:Partial Thromboplastin Time; D013927:Thrombosis / Q000188:drug therapy*
chemical_list: D000925:Anticoagulants; D000991:Antithrombins; D065427:Factor Xa Inhibitors; D000990:Antithrombin III; D006493:Heparin