Seal Zone Stability in Endovascular Repairs

• In traditional invasive open aortic surgery, a polymer tube graft is sutured to the aorta.
• In EVAR and TEVAR, the endograft and aorta are held together simply by adhesive forces over a short region of the repair called the seal zone.
• Seal zone failure can lead to endoleaks where blood flows in between the endograft and aorta.
• Endoleaks lead to repeat re-pressurization of the weakened aortic wall and increases the risk of aortic rupture and patient death.

Our hypothesis: geometric incompatibility dictates interfacial stability

• There is a competition between destabilizing displacement forces and loads acting on the endograft and stabilizing fixation forces.
• We apply fracture mechanics with a cohesive zone model for FEM to describe seal zone failure.
• Loss of seal correlates with the appearance of high stress in the aortic neck.
• The elasto-adhesive seal model balances the available elastic energy in the aortic neck with the interfacial energy.