ABSTRACT
Computational models of aortic dissection can provide novel insights into possible mechanisms by which this potentially lethal condition develops and propagates. We present results from a phase-field based finite element simulation of a classical experiment that had not previously been understood. Initial simulations agreed qualitatively and quantitatively with the experimental findings, but because of the complexity of the boundary value problem it was still difficult to build intuition. Hence, simplified analytical models were extended to gain further insight. Together, the simplified models and phase-field simulations revealed a power-law-based relation between the pressure required to initiate an intramural tear and key geometric and mechanical factors – area of the initial insult, stiffness of the wall, and characteristic energy of tearing. The degree of axial stretch and luminal pressure similarly influenced the value of the tearing pressure, which was ∼70 kPa for a healthy aorta having a sub-millimeter-sized initial insult but even lower for larger tear sizes. Finally, the simulations showed that the direction a tear propagates can be altered by focal regions of weakening or strengthening, which can drive the tear towards the lumen (re-entry) or adventitia (rupture). Additional data are needed, however, on aortas having different predisposing disease conditions.
Competing Interest Statement
The authors have declared no competing interest.