Computational Simulation of Platelet Deposition and Activation: II. Results for Poiseuille Flow over Collagen

Abstract

We have previously described the development of a two-dimensional computational model of platelet deposition onto biomaterials from flowing blood (Sorensen et al., Ann. Biomed. Eng. 27:436-448, 1999). The model requires estimation of four parameters to fit it to experimental data: shear-dependent platelet diffusivity and three platelet-deposition-related reaction rate constants. These parameters are estimated for platelet deposition onto a collagen substrate for simple parallel-plate flow of whole blood in both the presence and absence of thrombin. One set of experimental results is used as a benchmark for model-fitting purposes. The "trained" model is then validated by applying it to additional test cases from the literature for parallel-plate Poiseuille flow over collagen at both higher and lower wall shear rates, and in the presence of various anticoagulants. The predicted values agree very well with the experimental results for the training cases, and good reproduction of deposition trends and magnitudes is obtained for the heparin, but not the citrate, validation cases. The model is formulated to be easily extended to synthetic biomaterials, as well as to more complex flows.

Mechanical Platelet Activation Potential in Abdominal Aortic Aneurysms

“…In the medium to large arteries, tens of millions to billions of platelets can pass through the artery each second [39], making direct tracking of physiological platelet counts computationally infeasible in such domains. Instead, some researchers have utilized an Eulerian framework, in which concentrations of activated platelets are tracked as a continuum quantity [40][41][42][43][44]. To date, these Eulerian frameworks have been applied to the biochemical activation of platelets, and use of such methods to investigate biomechanical activation has been less explored.…”

A Model Incorporating Some of the Mechanical and Biochemical Factors Underlying Clot Formation and Dissolution in Flowing Blood

“…For instance, the experimental results of Sorensen et al (1999b) for Poiseuille flow of human blood over collagen can also be captured using this model by suitably modifying the parameters governing the platelet-surface reactivity (the corresponding flux boundary condition). Experimental data is also available that reports the distribution of thrombi along the length of collagen coated surfaces (Hubbell and McIntire, 1986;Wagner and Hubbell, 1990), and these too can be simulated by the model when the boundary conditions are specified appropriately, and a suitable numerical scheme is adopted for simulations involving two spatial dimensions.…”

Dynamics of Thrombin Generation and Flux from Clots during Whole Human Blood Flow over Collagen/Tissue Factor Surfaces

“…The kinetics of the extrinsic tenase (TF/FVIIa), the intrinsic tenase (FIXa/FVIIIa), and prothrombinase (FXa/FVa) have been extensively measured (7)(8)(9) and kinetically modeled for plasma (10 -13) or purified enzymes with added lipid (14 -16) and platelet-rich plasma (17)(18)(19)(20). These prior kinetic studies explore rate processes in a closed and isotropic context (i.e.…”