Optimization of porous stents for endovascular repair of abdominal aortic aneurysms

Abstract

This study presents a simulation‐based methodology to design porous stents to induce suitable hemodynamic environments inside abdominal aortic aneurysm (AAA) sacs. In the proposed methodology, an optimization algorithm iteratively modifies the porosity distribution of the stent and executes a computational fluid dynamics (CFD) simulation to determine the effect of these changes on the hemodynamic conditions inside the aneurysm sac. The optimization iterations proceed until relevant hemodynamic parameters are within ranges prescribed a priori by the user as desirable to control the progression of the AAA. The resulting porosity distribution uniquely describes the porous stent design that can control the hemodynamic environment (eg, shear stress at the aneurysm wall, pressure distribution, residence time), reducing AAA rupture risks and improving treatment efficacy. To demonstrate its potential, the proposed methodology is applied to idealized AAA geometry under steady‐state flow conditions, though it may be easily applied to more complex AAA geometries under transient, pulsatile flow conditions. The proposed methodology has the potential to enable the design of a new generation of porous stents tailored to patient‐specific geometries and flow conditions, to improve patient outcomes.

Systematic Review of the Application of Computational Fluid Dynamics for Adult Aortic Diseases

“…This, coupled with peak systolic pressure load, was 18.56-23.8% higher in the dilated segment of the aorta, indicating that the combina-tion of lower WSS and higher pressure could contribute to increased risk for further expansion and aortic aneurysm rupture [28]. This association between lower WSS and higher pressure with aortic rupture has been supported by multiple other studies, in which lower WSS or time averaged WSS (TWSS), with higher oscillatory shear index (OSI), were more prone to expansion, dissection or rupture [29,30,39,40], compared to normal areas. However, most of these studies were limited by being comparative in nature, and only focusing on fluid dynamics indicators for specific patient groups, leading to selection biases.…”