Currently, abdominal aortic aneurysms (AAAs), which are a permanent dilation of the aorta, are treated surgically
when the maximum transverse diameter surpasses 5.5cm. AAA rupture occurs when the locally acting wall stress
exceeds the locally acting wall strength. There is a need to review the current diameter-based criterion, and so it may be
clinically useful to develop an additional tool to aid the surgical decision-making process. A Finite Element Analysis Rupture
Index (FEARI) was developed.
Ten patient-specific AAAs were reconstructed, and the corresponding wall stress computed. Previous experimental work
on determination of ultimate tensile strengths (UTS) from AAA tissue samples was implemented in this study. By combining
peak wall stress along with average regional UTS, a new approach to the estimation of patient-specific rupture risk
has been developed.
Ten cases were studied, all of which were awaiting or had previously undergone surgical AAA repair. A detailed examination
of these ten cases utilising the FEARI analysis suggested that there was a possibility that some of the AAAs may
have been less prone to rupture than previously considered.
It is proposed that FEARI, used alongside other rupture risk factors, may improve the current surgical decision-making
process. The use of FEARI as an additional tool for rupture prediction may provide a useful adjunct to the diameter-based
approach in surgical decision-making.