A Method for Patient-specific Assessment of Abdominal Aortic Aneurysm Rupture Risk Based on Geometric Biomechanics Factors. Clinical Validation Test

摘要

Abdominal aortic aneurysms (AAAs) rupture is one of the main causes of death in the world. This is a very complex phenomenon that usually occurs "without previous warning". Currently, criteria to assess the aneurysm rupture risk (peak diameter and growth rate) cannot be considered as reliable indicators. In order to improve the predicting of AAA rupture risk, it had been developed a simple method, where the main geometric parameters of aneurysms have been linked into six biomechanical factors, which have been combined to obtain a dimensionless rupture risk index, RI(t). Based on the initial results of the validation tests of this method a broader prospective randomized control study with two hundred and one patients at the Clinic Hospital of Valladolid-Spain using a new set of weighted coefficient values for each biomechanical factor has been carried out in this work. The outcomes of the present work have shown that it is possible to implement a clinical assessment of the AAA rupture risk through its geometric parameters. Defined quantitative indicator is easy to understand. It allows estimating the aneurysms rupture risks and is able to identify the ones that ruptures even when its peak diameter is less than the threshold value. It also identifies those cases where the rupture should not occur regardless the maximum diameter is greater than the rupture threshold value and consequently avoids the patients to be submitted to surgical procedure. According to the results, the most relevant geometric biomechanical factors are the deformation rate and the growth rate. Beside these ones, but less important, resulted the saccular index.