Computational Comparison Between a Classic Bifurcated Endograft and a Customized Model With "Dog Bone"-Shaped Limbs

Area of Science:

• Biomedical Engineering
• Medical Device Design
• Computational Fluid Dynamics

Background:

• Endovascular aneurysm repair (EVAR) is a common treatment for abdominal aortic aneurysms.
• Stent-graft design modifications aim to improve device performance and patient outcomes.
• The
• dog bone
• -shaped (DB) endograft is a novel design for challenging anatomies.

Purpose of the Study:

• To compare the hemodynamic characteristics of a classic bifurcated stent-graft with a DB endograft design.
• To analyze flow patterns, wall shear stress, and displacement forces using computational simulations.

Main Methods:

• 3D modeling and computational fluid dynamics (CFD) analysis were employed.
• Models simulated blood flow, comparing DB and classic bifurcated endografts of equal length.
• Key hemodynamic parameters quantified included time-averaged wall shear stress, oscillatory shear index (OSI), relative residence time (RRT), displacement forces, and maximum wall shear stress (WSS).

Main Results:

• The DB design exhibited higher displacement forces in the main body compared to the classic configuration.
• Maximum wall shear stress was highest at the iliac limbs for both designs, with the DB model showing higher peak values.
• The stenotic segments of the DB model displayed high stress but low OSI and very low RRT.

Conclusions:

• The DB endograft design is associated with increased displacement forces in the main body and elevated stresses in the iliac limbs.
• Regular imaging follow-up is crucial to evaluate the mid- and long-term clinical performance of the DB design.