Immersed-boundary-type models of intravascular platelet aggregation

The formation of platelet aggregates during blood clotting is modeled on two scales using ideas motivated by Peskin’s immersed boundary method. The microscopic scale models track individual platelets, their mechanical interactions with one another and the surrounding fluid, their detection of and response to chemical activators, and the formation of cohesive and adhesive ‘links’ between platelets and between platelets and the vascular wall. These models allow inclusion of detailed mechanisms of binding–unbinding, platelet stimulus-response, and chemistry on the platelets’ surfaces. The macroscopic scale models treat the same interactions in terms of concentrations of platelets and distributions of cohesive and adhesive links, and can be used to study platelet aggregation in vessels of clinical interest including the coronary and cerebral arteries. In both types of model, the development of platelet aggregates affects the fluid motion only through an evolving fluid force density, and consequently, Cartesian grid methods are effective in solving the model equations.