Influence of Edoxaban on Coagulability and Thrombin Generation: An in Vitro Study Focusing on Thrombelastography

Experimental protocol 1. On the day of experiment blood samples will be collected in 3.2% citrate tubes. 2. One citrated blood tube will be centrifuged to collect plasma for biomarker measurements (C-reactive protein (CRP), fibrinogen, von Willebrand factor (vWF), interleukin (IL)-6, p-selectin, plasminogen activator inhibitor (PAI)-1, matrix metalloproteinase (MMP)-9). 3. Blood samples will be incubated with different concentrations of edoxaban (no edoxaban, subtherapeutic range - 30 nM, therapeutic range -300 nM, and supratherapeutic range- 900 nM) (3). A) Cora® Hemostasis Analyzer System (Cora®) will be used to assess qualitative and quantitative assessment of the hemostatic properties of a blood sample in the presence or absence of edoxaban. The CORA is an integrated computer module with Ethernet connection capability and provides continuous resonance-frequency viscoelasticity measurements using a disposable four-channel microfluidic cartridge to determine simultaneous maximal platelet-fibrin clot strength, fibrin clot strength, and response to antiplatelet agents or anticoagulants. The cartridge has four channels - citrated Kaolin (CK) channel that measures platelet-fibrin clot strength, anti-Xa channel, DTI channel and FFC channel that measures contribution of functional fibrinogen. In addition, using the V-curve software, the following parameters of thrombin generation kinetics will be evaluated from the CK channel- R - Period of time of latency from the time that the blood was placed in the TEG® analyzer until the initial fibrin formation. This represents the enzymatic portion of coagulation. K - K time is a measure of the speed to reach a certain level of clot strength. This represents clot kinetics. alpha - measures the rapidity of fibrin build-up and cross-linking (clot strengthening). This represents fibrinogen level. MA - Maximum Amplitude is a direct function of the maximum dynamic properties of fibrin and platelet bonding via GPIIb/IIIa and represents the ultimate strength of the fibrin clot. This represents platelet function/aggregation. TMRTG - Time to maximum rate of thrombus generation. MRTG - Maximum rate of thrombus generation. TG - Total thrombus generated. TMRL - Time to maximum rate of lysis MRL - Maximum rate of lysis L - Total lysis D - Delta is the difference between R time and the time of initial split point (SP, mins) of the TEG tracing (R - SP), representing the time interval of greatest clot growth secondary to peak thrombin generation. B) Calibrated Automated Thrombogram® (CAT) System: Lag time, peak thrombin production, mean velocity rate index and endogenous thrombin potential (ETP) will be assessed by calibrated automated thrombogram in platelet poor plasma (Thrombinoscope by Stago).