Plasma Levels of Total and Free Tissue Factor Pathway Inhibitor (TFPI) as Individual Pharmacological Parameters of Various Heparins

The release of circulating tissue factor pathway inhibitor (TFPI) into plasma by heparins is thought to contribute to their overall anti-thrombotic activity. In the presented study in healthy volunteers, we measured the heparin-induced increase of circulating total and free TFPI antigen and the aXa- and aIIa activity after subcutaneous (s.c.) injection of 9000 aXa-U of four different heparins: unfractionated heparin (UFH) (13.0 kDa), a medium molecular weight (MW) heparin with a narrow MW range (HF) (10.5 kDa), certoparin (6.0 kDa) and enoxaparin (4.5 kDa). Based on the administration of equi-active aXa doses, certoparin induced the highest increase in total TFPI determined as AUC (p