Biomedical Engineering Reference
In-Depth Information
An optimal shape for idealized bypass graft geometry was obtained using a
genetic search built around a developed finite element solver and adding routines
evaluating objective functions. The solution exhibits the benefits of numerical shape
optimization in achieving grafts inducing small gradient hemodynamic flows and
minimizing reversed flow and residence times.
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Concluding Remarks
A computational finite element model for simulating blood flow in arteries is
presented. Blood flow is described by the incompressible Navier-Stokes equations
and the simulation is carried out under steady and pulsatile conditions. The accuracy
and efficiency of the blood simulation is tested considering two examples. In
the first example the finite element method is used to simulate blood flow in a
carotid artery bifurcation. Calculations of the flow field for the carotid artery are
in good agreement with those reported previously in the literature. The model was
able to simulate complex flow patterns in the carotid sinus like time-dependent
stagnation and reversed flow along the outer sinus wall where flow separation occurs
throughout the systolic deceleration phase.
The second example represents a step towards developing a formal optimization
procedure for surgery design. An optimal shape for an idealized bypass is proposed.
A major limitation of this study is the use of cylindrical models whereas param-
eterizations of patient specific models present significant challenges. Future work
should also consider the influence of compliant walls and the effect of uncertainties
in simulation parameters. Robust optimization that accounts for uncertainties could
identify solutions that are less sensitive to small changes in design parameters, thus
allowing a hospital surgical implementation.
Further studies will consider experimental data collected in clinical practice.
Acknowledgments
This work was partially done in the scope of project PTDC/SAU-
BEB/102547/2008, “Blood flow simulation in arterial networks towards application at hospital”,
financially supported by
FCT - Funda¸ao para a Ciencia e a Tecnologia
from Portugal.
References
1. Pedrizzetti G, Perktold K (2003) Cardiovascular fluid mechanics. Springer, New York
2. Su CM, Lee D, Tran-Son-Tay R, Shyy W (2005) Fluid flow structure in arterial bypass
anastomosis. J Biomech Eng 127:611-618
3. Maurits NM, Loots GE, Veldman AEP (2007) The influence of vessel elaticity and peripheral
resistance on the carotid artery flow wave form: a CFD model compared to in vivo ultrasound
measurements. J Biomech 40:427-436
4. De Santis G, Mortier P, De Beule M, Segers P, Verdonck P, Verhegghe B (2010) Patient-specific
computational fluid dynamics: structured mesh generation from coronary angiography. Med
Biol Eng Comput 48(4):371-380
