法洛氏四重症術後之肺動脈流場型態 分析 Analysis of flow patterns in pulmonary artery after repair of Tetralogy of Fallot Hung-Lin Wang June 14, 2006

Outlines Introduction & research motivations Governing equations Mesh design and boundary setup Analysis of flow patterns Results & discussion Conclusions National Taiwan University of Science and Technology

What is Tetralogy of Fallot (TOF)? This group includes: Pulmonary stenosis A ventricular septal defect Overriding aorta (the main blood vessel from the heart to the entire body is somewhat displaced) Right ventricular hypertrophy

Tetralogy of Fallot (problem) National Taiwan University of Science and Technology

Fundamental assumptions A fluid in the pulmonary artery is blood, but a fluid in this study is considered to be Newtonian and incompressible. The gravitational effect is neglected. No heat source and heat transfer in the flow field. National Taiwan University of Science and Technology

Governing Equations Continuity equation : Navier-Stokes equation : National Taiwan University of Science and Technology

Boundary Setup National Taiwan University of Science and Technology inlet outlet 0 T systolicdiastolic ρ = 1060 kg ‧ m -3 μ= kg ‧ m -1 ‧ s -1 LPA MPA RPA outlet b/f = Q b /Q f Q b : Backward volume in a cycle Q f : Forward volume in a cycle Tang, T., Chiu, I.S., Chen, H.C., Cheng, K.Y. and Chen, S.J., 2001, Comparison of pulmonary aterial flow phenomena in spiral and Lecompte models by computational fluid dynamics. The Journal of Thoracic and CardiovascularSurgery 122, pp

Mesh Design National Taiwan University of Science and Technology Mesh Number : Solid-Works TM CFD GEOM CFD ACE Model design Mesh design Boundary setup

National Taiwan University of Science and Technology Analysis of flow patterns

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b/f = 0.009b/f = 0.26

National Taiwan University of Science and Technology The flow patterns at different diameters of LPA when b/f = 0.522

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b/f = D L = 10 mmD L = 6 mm

National Taiwan University of Science and Technology Analysis of 3D streamlines

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Results and discussion

National Taiwan University of Science and Technology The results of b/f

The difference of netflow between LPA and RPA National Taiwan University of Science and Technology LPA angle(θ) = 107 o LPA angle(θ) = 95 o

National Taiwan University of Science and Technology Effects of angle between LPA and MPA

National Taiwan University of Science and Technology Variation of LPA and RPA b/f ratio with b/f of MPA N : number of patients b i : mesured value p i : predicted value

National Taiwan University of Science and Technology The relation of b/f in MPA and RPA

National Taiwan University of Science and Technology The relation of b/f in MPA and LPA

Conclusions (1) National Taiwan University of Science and Technology We use predicted flow patterns to explain why the b/f of LPA is higher than RPA. It is because the duration of regurgitation in LPA is longer than RPA. We can know if the b/f of MPA increases, so will b/fs of LPA and RPA. The difference of netflow between LPA and RPA is tiny when the b/f of MPA is low. On the contrast, the difference of netflow between LPA and RPA will increase if the b/f of MPA is raised.

The b/f of LPA is higher than RPA both in this study and the mesured data of the hospital. The b/f of LPA will decrease if the angle between LPA and MPA increased. The variation of b/f ratio of LPA and RPA is not obvious when the b/f of MPA is greater than 0.2. Conclusions (2) National Taiwan University of Science and Technology

Thanks for your patience National Taiwan University of Science and Technology