Numerical simulation of compliant artery bypass grafts using fluid-structure interaction framework.

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Fluid Dynamics

Background:

• Traditional artery bypass graft (ABG) research often assumes rigid vessel walls, neglecting crucial wall compliancy.
• This simplification may lead to less realistic hemodynamic parameter assessments.
• Understanding vessel wall mechanics is vital for improving graft design and patient outcomes.

Purpose of the Study:

• To investigate the impact of compliant vessel walls on hemodynamic parameters in artery bypass grafts (ABGs).
• To compare the performance of compliant helical-type ABGs against conventional designs.
• To identify potential risks associated with compliant vessel walls in ABG configurations.

Main Methods:

• A fluid-structure interaction (FSI) study was performed on a complete artery bypass graft (ABG).
• Simulations incorporated the mechanical properties of compliant vessel walls.
• Hemodynamic parameters and vessel wall deformations were analyzed under physiological conditions.

Main Results:

• Compliant vessel walls buffer blood flow by expanding diameter and reducing anastomosis angle, mitigating endothelial cell injury.
• Maximum vessel wall deformation occurred at peak pressure; deformation was negligible during diastole.
• While wall compliance did not quantitatively alter overall flow characteristics compared to rigid models, it highlighted intimal hyperplasia risks in helical ABGs due to geometry and flow asymmetry.

Conclusions:

• Compliant vessel walls offer a protective mechanism against endothelial cell injury in artery bypass grafts.
• The hemodynamic advantages of helical-type ABGs are enhanced with compliant walls.
• Compliant wall analysis reveals that helical ABGs may increase intimal hyperplasia risk at the toe region, necessitating careful design considerations.