Dacron graft as replacement to dissected aorta: A three-dimensional fluid-structure-interaction analysis

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Research

Background:

• Aortic dissection (AD) is a life-threatening condition requiring aortic repair.
• Dacron grafts are commonly used for aortic replacement surgery.
• Understanding the biomechanical response of these composite structures is crucial for patient outcomes.

Purpose of the Study:

• To investigate the fluid-structure interaction (FSI) in a composite human aortic segment-Dacron graft model.
• To analyze stress and strain profiles within the aortic wall layers and the graft under pulsatile, turbulent blood flow.
• To compare the predictive accuracy and computational cost of different material models (elastic vs. hyperelastic, isotropic vs. anisotropic).

Main Methods:

• Utilized three-dimensional FSI simulations in Abaqus.
• Employed elastic and hyperelastic material models, including the Holzapfel-Gasser-Ogden (HGO) model for anisotropic behavior.
• Simulated Newtonian, incompressible, pulsatile, and turbulent blood flow.

Main Results:

• Von Mises stress at the aorta-Dacron interface remained below the aorta's ultimate strength across all models.
• No significant radial displacement changes were observed at the material interface due to blood flow.
• The hyperelastic-anisotropic model (HGO) exhibited approximately three times the computational cost of the elastic-isotropic model.

Conclusions:

• The simulated Dacron graft demonstrates biomechanical stability at the aorta interface under physiological blood flow conditions.
• A trade-off exists between the accuracy of advanced material models (e.g., HGO) and computational expense.
• Careful consideration of model complexity versus computational resources is necessary for effective simulation of aortic graft performance.