Biomedical Engineering Reference
In-Depth Information
sumption of other simulations. The flow fields created by the tissue and mechanical
valves, showed breakdown of vortices into small-scale vortical structures before
peak systole in mechanical heart valves, which is not observed in the bio-prosthetic
heart valves.
Chandran and Vigmostad (2013) discuss several studies suggesting mechanical
stresses induced on the valve leaflets and the abnormal flow development in the as-
cending aorta may be an important factor in the diseases of the valve and the aortic
root. They present details of the computational method in creating a patient-specific
geometry of the normal tri-cuspid and bicuspid valves from real-time 3D ultrasound
images and the dynamic analyses performed to determine the potential effects of
mechanical stresses on the valve leaflet and aortic root pathology. Their preliminary
results are shown in Fig.
9.10c
.
Such high level analysis provides insight and fine details of the flow patterns
which are not easily visualised with in vivo observations. The simulations also re-
veal complex kinematics of the valve leaflets, thus, underscoring the need for pa-
tient-specific simulations of heart valve prosthesis and other cardiac devices, which
can form part of the simulation-based virtual platform discussed in Sect. 9.5.
9.7
Summary
Haemodynamics plays an important role in the development and progression of
cardiovascular disease. Many researchers are at the frontiers of different topics,
and this chapter provides just a sample of the high level research currently being
undertaken. In blood rheology studies, the computational resources being used are
phenomenal reaching teraflops in computing speeds, and accounting for millions
of red blood cells simultaneously. Advanced medical imaging modalities are at a
level where they can complement fluid flow analysis providing insight into, and
validation of the computational model algorithms. This unique method is highly
beneficial for blood flow that is otherwise difficult to replicate in-vivo (unlike for
other fluids) due to its physiological nature. Ventricular devices and artificial heart
valves are also designed based on haemodynamics simulations to ensure the de-
signs produce sufficient shear stress for platelet activation, and reduce the risk of
thrombosis. The discussions in this section provide a basis for understanding the
advanced topics that will continue to push the boundaries of computational model-
ling as new algorithms and computational power become available.
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