Modelling of platelet–fibrin clot formation in flow with a DPD–PDE method

International audience; The paper is devoted to mathematical modelling of clot growth in bloodflow. Great complexity of the hemostatic system dictates the need of usage of themathematical models to understand its functioning in the normal and especially inpathological situations. In this work we investigate the interaction of blood flow,platelet aggregation and plasma coagulation. We develop a hybrid DPD–PDE modelwhere dissipative particle dynamics (DPD) is used to model plasma flow and platelets,while the regulatory network of plasma coagulation is described by a system of partialdifferential equations. Modelling results confirm the potency of the scenario of clotgrowth where at the first stage of clot formation platelets form an aggregate due toweak inter-platelet connections and then due to their activation. This enables the formationof the fibrin net in the centre of the platelet aggregate where the flow velocity issignificantly reduced. The fibrin net reinforces the clot and allows its further growth.When the clot becomes sufficiently large, it stops growing due to the narrowed vesseland the increase of flow shear rate at the surface of the clot. Its outer part is detachedby the flow revealing the inner part covered by fibrin. This fibrin cap does not allownew platelets to attach at the high shear rate, and the clot stops growing. Dependenceof the final clot size on wall shear rate and on other parameters is studied.