**7. Conclusions**

102 Aneurysm

**6. General** 

approach.

up to 75% of all cases;

4. Solution of unknown nodal displacements: The global balance equation is modified to take into account the boundary conditions of the problem and to obtain algebraic

5. Calculation of stresses and strains of the elements: Knowing the nodal displacements resulting from the previous stage, it could be calculated the stresses and strains using

6. Evaluation of results: the stresses solutions are obtained (and displacements in some models) along theaneurysm. It is possible to locate the exact point of the aneurysm where it produces the maximum stress and the value thereof. Figure 8, shows the surface distribution of stresses. The red color indicates the region with higher values of

equations where the unknowns are nodal displacements.

the corresponding mechanical equations.

stress and therefore, with greater risk of rupture.

**Figure 8.** Stress distribution in the arterial wall obtained by finite element simulation.

At this point, it is important to highlight two aspects. The first one is that the accumulation of knowledge around the topic of accurate prediction of AAA rupture is large enough and significant advances have been achieved in last years although the physicians continue using the same criteria. The second one is related to the growing consensus that it is possible to improve the reliability of the AAA rupture assessment by means of the biomechanical

Despite the growing interest for the behaviour of all these factors, many physicians question its clinical utility advocating the difficulties in its assessing during the everyday clinical practice. Often, these procedures require sophisticated software, very specific and accurate correlations and highly qualified personnel. This feeling appears clearly reflected in a survey carried out among vascular surgeons [85], whose outcomes are summarized in:

90% of the institutions rely their rupture risk estimation on the maximum diameter and the

40% of the institutions think that using their criteria, the rupture risk of AAAs is reliable in

expansion rate, whereas only 15% use the high mechanical stress criteria;

Aneurysmal disease and its progression is a very complex multifactorial process and its statistics are of great concern. The biomechanical approach here developed and substantiated can predict the rupture potential of a patient-specific AAA in any stage of evolution with sufficient accuracy to be clinically relevant. This predictive model is conceived by the integration of biological, morphological and structural information and can constitute a significant step in the clinical management of patients with aneurysm. Nowadays, we are developing a broader validation test of the proposed model by establishing its statistical signicance with a large enough number of AAA cases.
