FLOW-INDUCED WALL PRESSURE UNDER AVERAGE RESTING HEMODYNAMIC CONDITIONS FOR PATIENT-SPECIFIC ABDOMINAL AORTIC ANEURYSMS

摘要

Abdominal Aortic Aneurysms (AAAs) are characterized by a continuous dilation of the infrarenal segment of the abdominal aorta. Despite significant improvements in surgical procedures and imaging techniques, the mortality and morbidity rates associated with untreated ruptured AAAs are still outrageously high. AAA disease is a health risk of significant importance since this kind of aneurysm is mostly asymptomatic until its rupture, which is frequently a lethal event with an overall mortality rate in the 80% to 90% range. From a purely biomechanical viewpoint, aneurysm rupture is a phenomenon that occurs when the mechanical stress acting on the dilating inner wall exceeds its failure strength. Since the internal mechanical forces are maintained by the dynamic action of blood flowing in the aorta, the quantification of the hemodynamics of AAAs is essential for the characterization of their biomechanical environment. We have recently reported pulsatile blood flow patterns and shear stresses in a patient-specific AAA model and performed a comparison between its hemodynamic pressure and wall stress distribution. The purpose of this work is to address the hypothesis that hemodynamic pressure does not vary significantly along the inner AAA wall, and that its magnitude and distribution is dependent on the shape and size of an aneurysm. To achieve this objective, we numerically estimated flow-induced wall pressure in two patient-specific AAA models and compared the results.