Abstract: PO0504
Effects of Smoothing Methods on Hemodynamic Assessment of a Human Arteriovenous Graft
Session Information
- Bioengineering: Organoids and Organs-on-a-Chip
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Bioengineering
- 300 Bioengineering
Authors
- Fairbourn, Brayden, The University of Utah, Salt Lake City, Utah, United States
- Northrup, Hannah M., The University of Utah, Salt Lake City, Utah, United States
- Le, Ha D.H., The University of Utah, Salt Lake City, Utah, United States
- Shiu, Yan-Ting Elizabeth, The University of Utah, Salt Lake City, Utah, United States
- Cheung, Alfred K., The University of Utah, Salt Lake City, Utah, United States
Background
Aberrant hemodynamics contribute to the formation of neointimal hyperplasia in arteriovenous grafts (AVG) for hemodialysis, but the detailed hemodynamic environment in an AVG is unclear. Computational fluid dynamics (CFD), while a useful tool for hemodynamic analysis, is influenced by lumen geometry. 3D vascular lumens reconstructed from medical images must be smoothed to remove surface deformities and improve their uniformity before being used in CFD. We investigated whether different smoothing methods may cause different hemodynamic analysis results.
Methods
MRI scans were performed on a dialysis patient’s AVG and then used to reconstruct a 3D AVG lumen, on which four smoothing methods were applied that vary in their uses of interpolation, unconstrained smoothing, and additional surface smoothing (Fig 1A, B). The four smoothed lumens were used in the same CFD protocol to calculate velocity, wall shear stress (WSS), and oscillatory shear index (OSI). Results from different methods were compared using standard deviation (SD) and relative standard deviation (RSD = SD/mean x 100%)(Fig 1C).
Results
All methods give similar AVG lumen areas (RSD<3%). Although velocity has RSDs of 6-9%, their SDs are <0.1 m/s, and thus the differences are not considered biologically significant. Along the same line, all methods do not give biologically significant differences in OSI, as the SDs are <0.01. However, different smoothing methods give very different WSS, with RSD >12% and large SDs.
Conclusion
A variety of smoothing methods can be used to create AVG lumen reconstructions for CFD and hemodynamic analysis. These different methods can lead to significantly different WSS values. Therefore, researchers should consider the smoothing techniques used to characterize the hemodynamic environment in an AVG.
Funding
- NIDDK Support