Elsevier

Thrombosis Research

Volume 127, Issue 3, March 2011, Pages 275-276
Thrombosis Research

Letter to the Editors-in-Chief
The contribution of Tissue Factor Pathway Inhibitor to Thrombin Generation in children receiving Unfractionated Heparin

https://doi.org/10.1016/j.thromres.2010.11.011Get rights and content

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Materials and Methods

This was a prospective, single centre, cohort study. Samples were collected from children up to 16 years of age admitted to inpatient units of the Royal Children's Hospital (RCH), Melbourne, Australia, receiving a continuous infusion of at least 10 IU/kg/hr of UFH. Patients admitted to the paediatric and neonatal intensive care units were not included in this study. Informed consent was obtained from the parents of the children approached for participation. This study was approved by the Royal

Results

Samples were collected from 17 children admitted to the RCH between February and July 2009. Demographic and clinical information of the patients is summarised in Table 1.

Across the overall population, following a continuous IV infusion of UFH, the mean free TFPI concentration was 30.32 ± 7.08 ng/ml and the ETP before adding anti- TFPI antibodies was 122 ± 10 pM.min. Following the inhibition of TFPI, the ETPincreased by 12.0 ± 8.0 percent (p = 0.01) from the ETP recorded before addition of anti-TFPI

Discussion

Although the anticoagulant activity of UFH is significantly influenced by TFPI, no studies to date have investigated the UFH-induced TFPI release in paediatric populations. By measuring free TFPI release in children receiving continuous UFH infusion, this is the first study to demonstrate an AT-independent activity of UFH in the haemostatic system of children.

As expected, due to the anticoagulant activity of UFH, a reduction in the ETP before adding anti- TFPI antibodies, and an increase in

Summary

UFH predominantly acts by binding to and increasing the natural anticoagulant activity of Antithrombin (AT) and Tissue Factor Pathway Inhibitor (TFPI). A number of in vitro and in vivo studies have demonstrated clear differences in the AT-dependent activity of UFH in children compared with adults. However, there are no studies to date, directly observing UFH-dependent TFPI release in children receiving UFH via a continuous intravenous (IV) infusion. The results of our study are in accordance

Conflict of interest statement

None.

Acknowledgements

Mandira Hiremath was supported by the Royal College of Pathologists of Australasia (RCPA) Medical School Scholarship.

References (9)

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