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In vivo age dependency of unfractionated heparin in infants and children

Fiona Newall1, Vera Ignjatovic, Robyn Summerhayes

  • 1Department of Pathology, The University of Melbourne, Parkville, VIC 3010. fiona.newall@rch.org.au

Thrombosis Research
|October 3, 2008
PubMed

Insights

Unfractionated Heparin (UFH) dosing in children shows age-dependent effects on anticoagulant response. This study highlights that UFH

Area of Science:

  • Pediatric Pharmacology
  • Thrombosis and Hemostasis
  • Pharmacokinetics and Pharmacodynamics

Background:

  • Unfractionated Heparin (UFH) is widely used in pediatric care, but dosing guidelines are often based on adult data.
  • Existing in vitro studies suggest that current UFH practices may not be optimal for pediatric patients.
  • There is a need to better understand how age influences UFH response in vivo within the pediatric population.

Purpose of the Study:

  • To investigate the impact of patient age on the in vivo response to Unfractionated Heparin (UFH) in pediatric patients.
  • To compare UFH efficacy across different pediatric age groups.
  • To determine if age-related differences in UFH response are linked to Antithrombin levels.

Main Methods:

  • Prospective, observational study in a Pediatric Intensive Care Unit (PICU).
  • Included patients aged 16 years or younger receiving UFH at a minimum dose of 10 U/Kg/hr.
  • Laboratory analyses included Antithrombin, Activated Partial Thromboplastin Time (APTT), Anti-Xa, Anti-IIa, and thrombin generation (Endogenous Thrombin Potential), with results stratified by age groups (<1, 1-5, 6-10, 11-16 years).

Main Results:

  • 85 pediatric patients received UFH for a median of 3 days.
  • Lower Antithrombin levels were observed in children up to 11 years compared to age-related norms.
  • Anti-Xa values showed a trend towards lower activity in younger children, with all infants <1 year falling outside the therapeutic range.
  • Endogenous Thrombin Potential indicated increased inhibition in older children, suggesting age-dependent UFH effects not solely explained by Antithrombin levels.

Conclusions:

  • The in vivo anticoagulant and antithrombotic effects of a standard UFH dose are demonstrably age-dependent in pediatric patients.
  • Observed differences in Anti-Xa, Anti-IIa activity, and thrombin generation inhibition are not exclusively attributable to Antithrombin levels.
  • Further clinical studies are essential to establish optimal UFH dosing strategies tailored to specific pediatric age groups.
Abstract

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