Investigation of the Relationship Between Abdominal Aortic Aneurysm Rupture and\ud Mechanical Stress

The factors that cause abdominal aortic aneurysm rupture were investigated. Included\ud in this study were aneurysm volume, thrombus thickness, lumen area, thrombus area,\ud the average stress acting on the aorta, and the maximum stress on the aorta. The\ud geometric values were obtained by tracing a series of computerized axial tomography\ud (CT) scans for each patient to obtain a series of cross sections of the lumen and the\ud thrombus. The cross sections were then put through a program that found a best fit\ud surface for both the lumen and the thrombus. These meshes were analyzed to obtain\ud the geometric information. The stress data were calculated by using the meshes to\ud make an ADINA file programmed with average human values for outlet pressure,\ud flow rate of blood, and load pressure. This resulted in a model of each patient’s aorta\ud with the stress values included. A binomial logistic regression analysis revealed that\ud none of the parameters investigated here were able to predict a rupture with a high\ud degree of confidence (p