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aktualisiert am 17. Mai 2019
978-3-8439-0134-5, Reihe Medizintechnik
Mehdi Johannes Behbahani
Modeling and Simulation of Shear-Dependent Platelet Reactions in Blood Vessels and Blood-Contacting Medical Devices
240 Seiten, Dissertation Rheinisch-Westfälische Technische Hochschule Aachen (2011), Softcover, A5
Thrombosis-related complications are among the main causes leading to the death of patients who depend on medical devices. A mathematical model to describe thrombocyte reactions is presented and validated with respect to selected test cases.
The model is based on a continuum approach in which blood is treated as a single- phase, Newtonian fluid. The distribution of resting and activated platelets as well as of the platelet-activating substance ADP (adenosine diphosphate) is described by an advection- diffusion-reaction approach. The model includes chemical and shear-induced activation of thrombocytes, their aggregation behavior and adhesion of platelets to thrombogenic surfaces. The model is directed towards the prediction of thrombocyte behavior in res ponse to the governing flow conditions as they typically occur in blood vessels and body function assisting medical devices. The presented numerical method and implementation allow for the use of massive parallel computing resources.
The model validation is performed in comparison to experiments with whole blood or platelet rich plasma in a parallel plate chamber, a stagnation point perfusion chamber, a cylindrical gap, and in a replica of a stenotic coronary artery.
Moreover, comprehensive measurement data is presented for the behavior of blood in cylindrical gap flow. Specifically, thrombocyte reactions in Couette and stable Taylor- vortex flow are experimentally and numerically studied. A binding mechanism change from fibrinogen-mediated to VWF-mediated adhesion is detected.
The validation of the model with respect to experimental measurements indicates that the model is able to describe platelet reactions with respect to the governing flow conditions and to reproduce and explain to a certain extent qualitative and quantitative experimental data.