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J Surg Res. 2004 Feb;116(2):305-13.
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Computational fluid dynamic study of flow optimization in
realistic models of the total cavopulmonary connections.
Hsia TY, Migliavacca F, Pittaccio S, Radaelli A, Dubini G, Pennati G, de
Leval M.
Bioengineering and Structural Engineering Department, Politecnico di Milano,
Milan, Italy. [email protected]
OBJECTIVES AND BACKGROUND: In the Fontan circulation, pulmonary
and systemic vascular resistances are in series. The influence of various
inferior vena cava to pulmonary artery connections in this unique circulatory
arrangement was evaluated using computation fluid dynamics methods.
METHODS: Realistic three-dimensional models of total cavopulmonary
connections were created from angiographic measurements to include the
hepatic vein, superior vena cava, and branches of the pulmonary arteries.
Steady-state finite volume analyses were performed using identical in vivo
boundary conditions. Computational solutions calculated the percent hydraulic
power dissipation and left-to-right pulmonary arterial flow distribution.
RESULTS: Simulations of the lateral tunnel, intra-atrial tube, extracardiac
conduit with left and right pulmonary artery anastomosis demonstrated
extracardiac conduit with left pulmonary artery anastomosis having the lowest
energy loss. Varying the extracardiac conduit from 10 to 30 mm resulted in the
least energy dissipation at 20 mm. Serial dilation of the lateral tunnel pathway
showed a small incremental worsening of energy loss. CONCLUSIONS:
Maximizing energy conservation in a low-energy flow domain, such as the
Fontan circulation, can be significant to its fluid dynamic performance.
Although computational modeling cannot predict postoperative failure or
functional outcome, this study confirms the importance of local geometry of
the surgically created pathway in the total cavopulmonary connection.
J Biomech Eng. 2003 Dec;125(6):805-13.
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Computational fluid dynamics simulations in realistic 3-D
geometries of the total cavopulmonary anastomosis: the influence
of the inferior caval anastomosis.
Migliavacca F, Dubini G, Bove EL, de Leval MR.
Laboratory of Biological Structure Mechanics, Dept. of Bioengineering and
Dept. of Structural Engineering, Politecnico di Milano, Milano, Italy.
[email protected]
Fluid dynamics of Total Cavo-Pulmonary Connection (TCPC) were studied in
3-D models based on real dimensions obtained by Magnetic Resonance (MR)
images. Models differ in terms of shape (intra- or extra-cardiac conduit) and
cross section (with or without patch enlargement) of the inferior caval (IVC)
anastomosis connection. Realistic pulsatile flows were submitted to both the
venae cavae, while porous portions were added at the end of the pulmonary
arteries to reproduce the pulmonary afterload. The dissipated power and the
flow distribution into the lungs were calculated at different values of
pulmonary arteriolar resistances (PAR). The most important results are: i)
power dissipation in different TCPC designs is influenced by the actual cross
sectional area of the IVC anastomosis and ii) the inclusion of a patch
minimizes the dissipated power (range 4-13 mW vs. 14-56 mW). Results also
show that the perfusion of the right lung is between 15% and 30% of the
whole IVC blood flow when the PAR are evenly distributed between the right
and the left lung.