research paper: Clinical use of unfractionated heparin therapy in children: time for change?
Article first published online: 2 SEP 2010
© 2010 Blackwell Publishing Ltd
British Journal of Haematology
Volume 150, Issue 6, pages 674–678, September 2010
How to Cite
Newall, F., Ignjatovic, V., Johnston, L., Summerhayes, R., Lane, G., Cranswick, N. and Monagle, P. (2010), research paper: Clinical use of unfractionated heparin therapy in children: time for change?. British Journal of Haematology, 150: 674–678. doi: 10.1111/j.1365-2141.2010.08302.x
- Issue published online: 2 SEP 2010
- Article first published online: 2 SEP 2010
- Received 21 April 2010; accepted for publication 1 June 2010
- inter-assay correlation;
- paediatrics; therapeutic ranges;
- unfractionated heparin
Paediatric recommendations for unfractionated heparin (UFH) management are extrapolated from adult trials, a practice that may contribute to the inferior UFH-related outcomes in children compared to adults. This is the first study to determine UFH concentration in a population of children and correlated UFH concentration with measures of UFH effect. Correlation coefficients between protamine titration (concentration) and activated partial thromboplastin time (APTT), anti- activated factor X (Xa) assay and thrombin clotting time (effect) were 0·59, 0·46 and 0·52 respectively. A protamine titration level of 0·2–0·4 iu/ml in children was not equivalent to an anti-Xa assay of 0·35–0·7 iu/ml but to an anti-Xa assay 0·17–0·85 iu/ml. In addition, use of the anti-Xa or protamine titration assays to establish an APTT therapeutic range resulted in upper limits of APTT ranges exceeding 200 s. Existing methods for determining therapeutic ranges for UFH in adult populations do not produce equivalent ranges in children. As a result, paediatric clinical guidelines that state a therapeutic range for UFH can be determined using a protamine titration assay of 0·2–0·4 iu/ml or an anti-Xa assay of 0·35–0·7 iu/ml are not based on appropriate evidence. There is an urgent need for change in our approach to the use of UFH in children.