EVALUATING DESIGN OF ABDOMINAL AORTIC ANEURYSM ENDOGRAFTS IN A PATIENT-SPECIFIC MODEL USING COMPUTATIONAL FLUID DYNAMICS

摘要

Design and evaluation of implantable medical devices often relies on benchtop testing using physical models and animal studies. Although both methods are needed, they can be costly to implement and unable to represent patient-specific physiologic conditions. Computer simulations of blood flow in patient-specific anatomies offer an attractive alternative [1]. Abdominal aortic aneurysms (AAAs) are the 13th leading cause of death for males in the United States, with endovascular aneurysm repair (EVAR) becoming a popular alternative to traditional, open surgical repair. Although EVAR offers faster recovery times and the ability to treat patients who may otherwise not be eligible for open repair, endografts may shift in position over time. The shift in endograft position is attributed to the pulsatile nature of blood flow and the resulting forces [2]. There are several FDA-approved endografts currently available in the U.S. market. A key feature of each endograft's geometry is the location at which its body bifurcates into two limbs, which then extend into the iliac arteries. In this study, we use CFD to evaluated three device designs in a patient-specific model built using 3D segmentation techniques. The first model (Proximal Bifurcation) featured an entirely double lumen design. The second model (Mid Bifurcation) was created with a bifurcation point mid-way between the renal arteries and the aortic bifurcation. The last model (Distal Bifurcation) divided into its two limbs at the aortic bifurcation. The displacement forces on the device in all three models were calculated.