Platelet-dependent hemostatic potential in the presence of DOACs

Introduction: Direct oral anticoagulants (DOACs) are the standard care for stroke prevention in non-valvular atrial fibrillation and managing venous thromboembolism. DOACs can cause major bleeding episodes in up to 5% of patients, making DOAC reversal strategies crucial in acute trauma or emergent surgery. Currently, andexanet alfa is the only DOAC reversal option for FXa dependent DOACs. However, major clinical limitations are known, including elimination of physiological anticoagulant protection and triggering prothrombotic adverse reactions. Additionally, its high costs makes provide a drawback. Here, we studied the effects of alternative, DOAC-reversal nanobodies on coagulation under flow. We aim to evaluate the capability of novel DOAC-reversing nanobodies to normalize anticoagulant effects on the platelet clot formation under flow using a novel microfluidic device.

Method: A novel microfluidic blood perfusion system was employed operating at wall shear rate (1000 s^-1) and at 37°C. Platelet-thrombus formation was evaluated from collagen/tissue factor surfaces by automated capturing of brightfield and fluorescence images during clot formation. Healthy donor blood was compared with DOAC-treated blood (300 nM edoxaban or 600 nM rivaroxaban) in presence or absence of nanobodies against specific DOACs (600 nM) or andexanet (600 nM).

Results: Blood treatment with either DOAC did not affect platelet deposition, but decreased thrombus contraction by 20-27% (P<0.05). Simultaneously, both treatments delayed and impaired fibrin formation, reducing fibrin deposition at 10 minutes by 70%-83%, depending on the DOAC used (41 SAC% vs. 8.2-14.5 SAC%, P=0.012-0.049). Each nanobody against the respective DOAC counteracted the inhibitory effects and essentially restored coagulant function (8.2 SAC% vs 41.7-44.5 SAC% fibrin deposition, P=0.009-0.047). Andexanet alfa caused a similar reversal capacity (P=0.016).

Conclusion: This in vitro analysis indicated that the developed nanobodies against rivaroxaban and edoxaban restore the hemostatic process after DOAC treatment, and hence provide a promising strategy to reverse DOAC-dependent bleeding complications.

Publikationsverlauf

Artikel online veröffentlicht:
13. Februar 2025