Volumen: 17 # Number : 3
Publication Date : Septiembre - Diciembre Year: 2013
Effect of first and second generation LMWH
on thrombin generation parameters
Authors: Duboscq C, Ceresetto J, Stemmelin G, Shanley C,
Rabinovich O, Palmer S, Bullorsky EO
Abstract: The aim of this study is to investigate the effect of enoxaparin
(E), Anti Xa/anti IIa activity ratio: 3.9/1 and bemiparin
(B), Anti Xa/Iia activity ratio: 8/1on the TG test in presence of platelets. Methods: Platelet rich plasma from fifteen blood donors were spiked with increasing concentration
of E and B. Plasma of patients treated with a prophylactic dose of E (n=10) or B (n=10) was obtained between 4 hours post subcutaneous injection. Anti Xa activity in spiked plasma and patient plasmas were measured
with chromogenic assay. For each LMWH a standard
curve with the same drug was performed. TG was measured in platelet rich plasma initiated by recombinant tissue factor 15μM and CaCl2, 10nM. For each sample we determined the index rate of propagation (IR), endogenous
thrombin potential (ETP), the lag phase (tlag), maximum
thrombin concentration (Tmax) and time (tmax) to reach Tmax. Results: In vitro, both anticoagulant decreased
ETP and IR in a concentration depend manner. The IC 50 (concentration, expressed as U anti Xa/ml, that diminished 50 % of each parameter) were: bemiparin (n=15) Tmax= 0.60±0.05; ETP= 0.75 ± 0.06; IR 0.56± 0.03 Enoxaparin: Tmax= 0.42 ± 0.01; ETP= 0.50±0.06; IR=0.41±0.01. All patients showed anti Xa activity for B= 0, 35 ±0.14 U anti Xa /ml and for E=:0.28 ±0.11UI U anti Xa/ml. All sample patients showed a reduction in ETP, IR and Tmax with a lag phase prolonged. Conclusions: In vitro studies B showed lower inhibitory activity towards TG than E according its lower anti IIa activity. However in these few patients samples E and B did not show any difference on TG parameters.
Key words: bemiparin-enoxaparin-thrombin generation
Pages : 231-237
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