Continuum Models of Platelet Aggregation: Formulation and Mechanical Properties

Platelet aggregation is an important component of the blood’s clotting response, and is associated as well with many forms of cardiovascular disease. A new class of continuum models of platelet aggregation is presented. The models describe interactions among a viscous, incompressible fluid and populations of nonactivated (nonsticky) and activated (sticky) platelets suspended in this fluid. Cohesion between activated platelets can profoundly influence the motion of the suspending fluid. A platelet-activating chemical triggers a platelet’s transition from nonactivated to activated status, and induces the secretion of more of the same chemical. Investigation of the mechanical properties of the fluid-platelet system in the absence of new activation shows that platelet cohesion can generate extra pressure and extra viscous and elastic stresses. The last is sufficient to maintain the integrity of an aggregate that is subject to substantial external stress.