Modelling peeling- and pressure-driven propagation of arterial dissection

Area of Science:

• Computational mechanics
• Biomedical engineering
• Cardiovascular research

Background:

• Arterial dissection involves a tear in the vessel wall, creating a false lumen.
• Dissection propagation can be rapid and life-threatening.
• Understanding dissection mechanics is crucial for clinical intervention.

Purpose of the Study:

• To develop and utilize a computational model for simulating arterial dissection propagation.
• To investigate the influence of material properties and tear geometry on dissection progression.
• To correlate computational findings with clinical observations of dissection patterns.

Main Methods:

• Employed the extended finite element method (XFEM) to model the tear.
• Utilized a cohesive traction-separation law to represent tear face behavior.
• Incorporated the anisotropic hyperelastic Holzapfel-Gasser-Ogden material model for arterial wall mechanics.
• Simulated dissection propagation under peeling and pressure-loading conditions.

Main Results:

• Dissection propagation preferentially occurred along material axes of greatest stiffness, dictated by fiber orientation.
• Pressure-driven dissections in a cylindrical model showed buckling of the inner wall for long, shallow tears.
• Buckling patterns observed in simulations closely matched clinical CT scan findings.
• Deeper arterial tears were found to be more prone to propagation.

Conclusions:

• The computational model accurately simulates arterial dissection and propagation patterns.
• Material anisotropy and tear depth significantly influence dissection progression.
• Simulated buckling phenomena provide insights into the biomechanics of dissection observed in patients.