Stress and strain behaviour modelling of the carotid bifurcation

The aim of this study is to investigate the biomechanical stress and strain behaviour within the wall of the artery and its influence on plaque formation and rupture using computational fluid dynamics (CFD).

A three-dimensional finite-element model of the carotid bifurcation was generated to analyse the wall stress and strain behaviour. Both single-layer and multilayer models were created and structural analysis was compared between these two types of models. Systolic pressure of 180 mm Hg (~24 kPa) was applied in the inner boundary of the carotid bifurcation, and CFD analysis was performed to show the wall shear stress and pressure.

The highest wall stress was found at the carotid bifurcation. When a high blood pressure (280 mm Hg) was applied to the carotid CFD model, the results showed that the stress at the carotid bifurcation may reach the rupture value. The multilayer carotid bifurcation model behaved differently from the equivalent single-layer model, with peak stress (Von-Mises) being higher in the multilayer model.

The peak stress and strain was located at the origins of the internal and external carotid arteries. Significant shearing occurred between the layers in the wall of the artery at the bifurcation. Intramural shear stress in the CFD multilayer model has potential for intramural vascular injury. This may be responsible for plaque formation, plaque rupture and an injury/healing cycle.