Effect of Geometric Accuracy at the Proximal Landing Zone on Simulation Results for Thoracic Endovascular Repair Patients.
PURPOSE
Existing hemodynamic studies on aortic dissection after thoracic endovascular aortic repair (TEVAR) apply geometric simplifications. This study aims to evaluate the necessity of more accurate geometries at the proximal landing zone in computational fluid dynamic (CFD) studies.


METHODS
Three patient-specific 3D aortic dissection models with different geometric accuracies at the proximal landing zone were manually fabricated for CFD simulations: (i) model 1 without the stent graft (SG), (ii) model 2 with the metal stent, and (iii) model 3 with the SG. The flow distribution, flow pattern, and wall shear stress (WSS)-related indicators in these three models were compared.


RESULTS
The flow distributions were quite similar for the three models, with a maximum absolute difference of 0.27% at the left suclavian artery (LSA) between models 1 and 3 because of partial coverage. A more chaotic flow pattern was observed at the proximal landing zone in model 3, with significant regional differences in the WSS-related indicator distributions. The upstream and downstream WSS-related indicator distributions were quite similar for the three models.


CONCLUSIONS
The flow pattern and hemodynamic parameter distributions were affected by the geometric accuracy only in a small region near the proximal landing zone. The flow split was hardly affected by the LSA partial coverage, indicating that the coverage may have slight effects on short-term blood perfusion. However, this conclusion needs to be verified in future studies with larger sample sizes.
['Qiu|Yue|Y|', 'Dong|Shiming|S|', 'Liu|Zhan|Z|', 'Yuan|Ding|D|', 'Zheng|Tinghui|T|0000-0002-0597-3245']
D000784:Aneurysm, Dissecting D001013:Aorta, Thoracic D017545:Aortic Aneurysm, Thoracic D001027:Aortography D001807:Blood Vessel Prosthesis D019917:Blood Vessel Prosthesis Implantation D000072226:Computed Tomography Angiography D016208:Databases, Factual D057510:Endovascular Procedures D006439:Hemodynamics D006801:Humans D057446:Hydrodynamics D008955:Models, Cardiovascular D066230:Patient-Specific Modeling D011474:Prosthesis Design D012039:Regional Blood Flow D012189:Retrospective Studies D015607:Stents
Proximal landing zone Thoracic endovascular aortic repair (TEVAR) Blood flow Computational fluid dynamic (CFD) simulation Left subclavian artery coverage