Thromb Haemost 1994; 71(03): 300-304
DOI: 10.1055/s-0038-1642434
Original Article
Schattauer GmbH Stuttgart

Ex-Vivo and In-Vitro Evidence that Low Molecular Weight Heparins Exhibit Less Binding to Plasma Proteins than Unfractionated Heparin

Edward Young
1  The Hamilton Civic Hospitals Research Centre and the Department of Pathology, McMaster University, Hamilton, Canada
,
Philip Wells
2  The Hamilton Civic Hospitals Research Centre and the Department of Medicine, McMaster University, Hamilton, Canada
,
Scott Holloway
3  The Dept. of Clinical Research and Development, Wyeth-Ayerst, Philadelphia, USA
,
Jeffrey Weitz
2  The Hamilton Civic Hospitals Research Centre and the Department of Medicine, McMaster University, Hamilton, Canada
,
Jack Hirsh
2  The Hamilton Civic Hospitals Research Centre and the Department of Medicine, McMaster University, Hamilton, Canada
› Author Affiliations
Further Information

Publication History

Received: 17 June 1993

Accepted after revision 09 December 1993

Publication Date:
06 July 2018 (online)

Summary

We have compared the non-specific binding of unfractionated heparin (UFH) with that of low molecular weight heparin (LMWFl) to plasma proteins both ex vivo and in vitro. Non specific binding to plas ma proteins was assessed by comparing the heparin levels measured as anti-factor Xa activity before and after the addition of low affinity heparin, which is essentially devoid of anti-factor Xa activity, in order to displace heparin bound to plasma proteins. For the ex-vivo studies, we compared the recovery of UFH and a LMWH (ardeparin) from the plasma of patients participating in a randomized trial of post operative venous thrombosis prophylaxis. For the in-vitro studies, we compared the recovery of UFH and 4 different LMWHs when added to the plasma from healthy volunteers and from patients with suspected venous thromboembolic disease. The results indicate that the recovery of LMWH is much less affected by nonspecific binding to plasma proteins both ex-vivo and in-vitro. In addition, there are differences between the LMWHs with respect to their plasma protein-binding.