Mechanical Evaluation of Stenting for Saccular Abdominal Aortic Aneurysm Using Fluid Structure Interaction Analysis: A Study on Stent Size

Abstract

We previously analyzed a saccular abdominal aortic aneurysm model and elucidated that saccular abdominal aortic aneurysms manifest abnormal hemodynamic factors from an early stage and that stenting improves hemodynamic factors. We analyzed a model of a saccular abdominal aortic aneurysm implanted with stents of different diameters and lengths to examine the optimal stent size to improve hemodynamic factors in this study. The stent diameter was set using three patterns as follows: 24 mm, the same as the aortic diameter; 26.4 mm, 10% increase; and 28.8 mm, +20% increase. The stent length was extended 10 mm vertically from the 28-mm length of the aneurysmal portion to 50 mm and 70 mm in two patterns, for a total of six types. The analysis revealed that all hemodynamic factors improved in all sizes compared with those prior to stenting. Streamlines entering the aneurysm were reduced with larger stent diameters; however, no difference in length was observed. Moreover, no clear differences in the mean flow velocity within the aneurysm, maximum shear stress, or pressure loss coefficient between the models were observed. The implanted stent was sufficient in terms of efficacy if it adhered to the aortic wall and covered the saccular aneurysm area.