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A hybrid (hydro-numerical) cardiovascular model: application to investigate continuous-flow pump assistance effect

Kozarski M., Ferrari G., Zieliński K., Górczyńska K., Pałko K. J., Fresiello L., Di Molfetta A., Darowski M.

Biocybernetics and Biomedical Engineering

2012

Vol. 32, no. 4

77-91

A hybrid (Hydro-numerical) model of blood circulation developed at the Institute of Biocybernetics and Biomedical Engineering (IBIB) of the Polish Academy of Sciences (PAN) -Warsaw, Poland, in co-operation with the Institute of Clinical Physiology (IFC) of the National Council of Research (CNR) - Rome, Italy, is a basic model of this type solutions commonly accepted by the researchers. It is able to simulate all essential hemodynamic functions of the human cardiovascular system including the heart. During last years, resumption of works on constant-flow non pulsatile rotary pumps to be used as heart support devices is observed because of their small dimensions and easier way of implantation. Control modes of rotary pumps are different and evidently influence heart support effects. The main aim of this paper was to investigate different control systems of rotary pumps in a role of the assist devices. To fulfill this task on the hybrid model, a special computer application was worked out. The investigations included: a) loading characteristics p(q) of the rotary pump assignment at two values of a control voltage - 18V, 24V; b) physiological and pathological states simulation including parallel atrial-aortic assistance by the rotary pump. The results of the simulations obtained on the model treated as a 'virtual patient' are in agreement with the data received in medical conditions.

A FEM study of aortic hemodynamics in the case of stenosis

Rinderu P. L., Rinderu E. T., Gruionu L., Bratianu C.

Acta of Bioengineering and Biomechanics

2003

Vol. 5, nr 2

45-52

In this report we use a real, two-dimensional geometry of a human abdominal aorta with mild stenosis from images obtained with a MR scanner. Finite element method was used for solving the governing equations for two-dimensional, steady, laminar flow of an incompressible, non-Newtonian fluid in that geometry. The accuracy with which the governing equations were solved using the finite element method was not examined quantitatively in the present study due to a lack of published data. Numerical results were found to be in excellent agreement with Womersley theory and with laser Doppler anemometry velocity data obtained for steady flow in a human model. The distributions of the velocity profile, wall shear stress and pressure along vessel during the cardiac cycle are shown. The results were compared to known values, and peaks were found. The shape of velocity distribution is strongly disturbed by the stenosis, and disturbance is clearly evident whatever instant of the cardiac cycle was considered. The general flow features were accurately predicted based on the finite element flow model, which allows the conclusion that computational fluid dynamics can be used to facilitate improvement of the medical research of cardiovascular physiology.