FEM Modeling of Patient-Specific AAA Treated With Endografts

Abdominal aortic aneurysm (AAA) rupture occurs when wall stress exceeds wall strength. Endografts aim to prevent rupture by reducing wall stress. However, after implantation, AAA may shrink, grow, or stabilize in diameter, even in the absence of apparent flow into the sac or pressurization. This may result in graft failure through loss of seal, kinking, or component separation. Insight from models of treated AAA could provide insight into treatment methods/limitations and for device design. The nature of the stress reduction in AAA by endograft treatment was modeled using FEM in two patients followed at three time points each (pre-treatment, early follow-up, and late follow-up) — one with a “stable” aneurysm and one with a “shrinking” aneurysm.