Aortic hemodynamic and morphological analysis before and after repair of thoracoabdominal aortic aneurysm using a G-Branch endograft

Figures

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  FIGURE 1. Illustrations of G-branch endografts and four zones in BSGs. (A) Compositions of G-branch endograft. (B) Four zones were plotted in a 3D model. (C) Vessel straightening and definition of four zones. Four zones were divided by five points, (I) the initial site of the BSGs; (II) the branched point; (III) the vessel branch point; (IV) the distal end of BSGs; (V) the bifurcation point. The branched zone between the initial sites of the BSGs (I) and the branched point (II); the bridging zone between the branched point (II) and the vessel branch point (III); the distal sealing zone between the vessel branch point (III) and the distal end of the BSGs (IV); and the native vessel zone between the distal end of the BSGs (IV) and the bifurcation point (V). (D–F) Cross sectional area measurements in BSGs and in renovisceral arteries. BSGs, bridging stent grafts.

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  FIGURE 2. Reconstruction of the three-dimensional model, meshing, and boundary conditions. (A) The inlet flow rate waveform. Five specific time points, namely, systolic acceleration (T1 = 0.10 s), maximum flow rate (T2 = 0.18 s), systolic deceleration (T3 = 0.32 s), minimum flow rate (T4 = 0.44 s), and mid-diastole (T5 = 0.68 s), were chosen to depict hemodynamic changes over a cardiac cycle. (B) Sketches showing mesh generation. (C) Segmentation of the region of interest and three-element Windkessel model applied on each outlet.

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  FIGURE 3. Cross-sectional area of bridging stent grafts and renovisceral arteries. (A) Cross-sectional area of the renovisceral arteries. The symbols show the median and the error bars showed the interquartile range. *p < 0.05; ***p 0.001; ****p < 0.0001; ns, not statistically significant. (B) Cross-sectional area by distance from the initial site of the bridging stent graft in 5-mm increments. The initial site of the bridging stent graft is assigned to zero on the x-axis. The distal sealing zones are shown as gray areas. The gray dotted line indicates the branched point. The areas on the left of the gray dotted line indicate the branched zones. The regions between the gray dotted line and the gray area represent the bridging zones, while the native vessel zones occupy the areas to the right of the gray areas. The black circles indicate stenosis in the vessels or stent grafts. CA, celiac artery; SMA, superior mesenteric artery; LRA, left renal artery; RRA, right renal artery; LCIA, left common iliac artery; RCIA, right common iliac artery.

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  FIGURE 4. Flow rate in outlets. The symbols show the median and the error bars indicate the interquartile range. *p < 0.05; ***p < 0.001; ****p < 0.0001; ns, not statistically significant. CA, celiac artery; SMA, superior mesenteric artery; LRA, left renal artery; RRA, right renal artery; LCIA, left common iliac artery; RCIA, right common iliac artery.

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  FIGURE 5. Velocity path lines in all models (t = 0.18 s, maximum flow rate). A, P, L and R denote the locations of the anterior, posterior, left and right walls, respectively.

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  FIGURE 6. Instantaneous velocity magnitudes of different cross-sectional planes in the right renal artery at five phases of the cardiac cycle. Plane 1 is from the branched zone; Plane 2 is from the bridging zone; Plane 3 is from the distal sealing zone; Plane 4 is from the native vessel zone. A and P denote the locations of the anterior and posterior walls, respectively.

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  FIGURE 7. Detailed velocity vector before and after surgery.

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  FIGURE 8. Distribution of time-averaged wall shear stress at four positions before and after surgery.

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  FIGURE 9. Distribution of relative resident time at four positions before and after surgery.

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  FIGURE 10. Scalar hemodynamic parameters before and after surgery.