Multiphase cardiovascular haemodynamics: impact of surface roughness and platelet activation

Owen, David Gwyn ORCID: 0000-0002-7774-6084 (2022). Multiphase cardiovascular haemodynamics: impact of surface roughness and platelet activation. University of Birmingham. Ph.D.

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Abstract

With cardiovascular diseases (CVD) being the leading cause of death worldwide, computational fluid dynamics can be used to provide insight into the onset and progression of CVD and to improve the design of medical devices. This thesis develops novel cardiovascular simulations to evaluate how the multiphase rheology of blood impacts CVD and the activation of platelets, with an assessment of haemodialysis catheter design. To date all cardiovascular models assume a smooth artery wall, despite microscopic surface roughness being linked to CVD. A simulation of artery roughness showed a greater range in haemodynamic parameters associated with CVD, compared to a smooth wall, with increased residence time in an ultra low-shear environment (<25 s-1). Stenosed coronary bifurcations were found to exhibit non-Newtonian and multiphase phenomena, with red blood cell residence time in aggregatory low-shear conditions found distal to stenosis. Increased levels of platelet activation and subsequent residence near the plaque highlight the mechanisms of atherothrombosis. Haemodialysis catheters were found to have improved performance with side-holes, however, to ensure long-term patency and reduce the chance of blood clots; the side-holes should be oval shaped, correctly scaled for body diameter, and with an angle-cut profile for optimal surface texture to reduce bio-fouling. Multiphase rheological blood models can be developed to better predict phenomena associated with CVD, yet require additional physical laws governing red blood cell aggregation and near-wall adhesion.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):