Risk of rupture analysis for advanced level of AAA under combined physiological and physical conditions

Abstract

The risk of rupture for advanced level of aneurysm is very much investigated by medical practitioners and researchers. Numerical modelers have also been contributing to the prediction of this rupture. In this study, the effect of various physiological and physical conditions to the increased of the risk rupture is investigated. This study uses simplified model of aneurysm based on actual shape for the advanced level of aneurysm. Three-dimensional model was used and various flow situations representing various physical conditions were evaluated. Both normal blood pressure (NBP) and high blood pressure (HBP) effect were studied in this case. This study shows that a person with advanced level of aneurysm is observed to have vortex formation as the flow reaches late systole, in the distal region under both resting and exercise conditions. This phenomenon will increase the risk of rupture due to the high fluctuation of wall shear stress in this area. Lower risk of rupture is also observed in the proximal area with the presence of weak vortex. The results also show that high blood pressure under exercise conditions exhibits approximately double the risk for rupture as compared to normal blood pressure under resting condition.