TITLE:
Hemodynamic Forces Effective in Reshaping Vascular Geometry
AUTHORS:
Erhan Kızıltan
KEYWORDS:
Patient Specific Simulation, Computational Hemodynamics, Wall Shear Stress, Shear Rate
JOURNAL NAME:
Open Access Library Journal,
Vol.2 No.7,
July
16,
2015
ABSTRACT: Besides the medical education, simulations became an attractive
diagnostic method in some clinical cases. Recent advances in computerized image
processing bring new practices entitled as “patient specific simulation” to the
agenda. One of the successful applications which examines hemodynamic forces as
a result of the interaction between blood flow and vessel wall constitutes the
topic of this study. In this study, the terms and laws which provided a
theoretical basis for the hemodynamic forces in circulatory system were
evaluated from the biophysical point of view. With this perspective, the concepts
of fluid viscosity and blood flow in elastic vessel were emphasized. The
impacts of height and vessel diameter differences on flow conditions were
discussed in terms of Bernoulli and continuity laws. Viscosity effect and the
other factors that may impede the fluid flow were discussed in accordance with
Poiseuille’s law. The relation between transmural pressure and dilatation in
elastic vessel was evaluated considering Laplace law. Then, the dynamic forces
in radial and axial directions occurring during fluid flow were defined. Clinically,
it is important to know the interactions between blood and vessel wall
endothelia. Current in-vivo methods
are not suitable for the measurements of spatial and temporal patterns of these
interactions. However, classical engineering method of computational fluid
dynamics, recently, took place in medical simulations that made it possible to
calculate the hemodynamic parameters for every volume element defined in
three-dimensional anatomically realistic vessel model. Patient specific
simulations that are believed to be the core of the future project of “clinical
diagnostic expert systems” will be an important tool in prescribing patient
specific treatment and in the assessment of complication risks. With this
perspective in this paper, we discussed the theoretical background and
elucidated the role of hemodynamic forces in vascular pathologies.