title: Retrospective evaluation of antithrombin III supplementation in neonates and infants receiving enoxaparin for treatment of thrombosis.
abstract: BACKGROUND
  Thromboembolic events are occurring at increasing rates in neonates and infants. At Children's Mercy Hospitals and Clinics, antithrombin III (AT3) concentrates are often used in combination with enoxaparin to supplement physiologically low AT3 levels. Theoretically, AT3 enhances the anticoagulant activity of enoxaparin and results in decreased time to therapeutic anti-Xa levels. No data exist on use of AT3 for this indication.
  
  
  METHODS
  This retrospective study compared time to therapeutic anti-Xa levels in patients <1 year of age receiving enoxaparin with AT3 (Group 1) and without AT3 (Group 2) for treatment of thrombosis. Primary objective was to compare time to therapeutic anti-Xa levels (0.5-1 U/ml) between groups. Secondary objectives included comparison of the initial and therapeutic dose of enoxaparin, enoxaparin dose changes, AT3 supplementation, and level monitoring. Bleeding events and cost were also evaluated. Statistical tests included Schuirmann's two one-sided tests for equivalence and general linear models/logistic regression for independent effects of age, critical illness, and timing of AT3.
  
  
  RESULTS
  Mean time to therapeutic anti-Xa levels were not equivalent between Groups 1 and 2 (80.7 vs. 65.2 hours; P = 0.28). Initial enoxaparin dose and number of dose changes were equivalent. Group 1 required higher doses of enoxaparin to achieve therapeutic anti-Xa levels. Age, critical illness, and timing of AT3 had no effect on time to therapeutic anti-Xa levels. Bleeding events were not equivalent between Groups 1 and 2 (14.3% vs. 3.9%; P = 0.55).
  
  
  CONCLUSIONS
  Supplementation with AT3 did not decrease time to therapeutic anti-Xa levels, added significant cost, and was associated with increased bleeding events.
authors.affiliation: Centennial Medical Center, Nashville, Tennessee.
authors.forename: Amy
authors.initials: A
authors.lastname: Corder
authors.forename: Kristin
authors.initials: K
authors.lastname: Held
authors.forename: Alexandra
authors.initials: A
authors.lastname: Oschman
mesh_terms: D000367:Age Factors; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D000990:Antithrombin III / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D016638:Critical Illness; D004305:Dose-Response Relationship, Drug; D016527:Drug Costs; D004341:Drug Evaluation; D016903:Drug Monitoring; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D017984:Enoxaparin / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D065427:Factor Xa Inhibitors; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D013927:Thrombosis / Q000188:drug therapy* / Q000517:prevention & control; D013997:Time Factors
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D065427:Factor Xa Inhibitors; D000990:Antithrombin III
keywords: anticoagulation; hematology: hemostasis and thrombosis; intensive care; neonatology; pharmacology; thrombosis