Effects of Microporous Stent Graft on the Descending Aortic Aneurysm: A Patient-Specific Computational Fluid Dynamics Study

Thoracic endovascular aortic repair (TEVAR) method is an alternative treatment for thoracic aortic aneurysm (TAA) compared to open surgery. It is believed that stent graft implantation can potentially reduce the risk of aneurysm rupture by altering the associated blood flow disturbances within an aneurysm. To investigate the hemodynamics changes of TEVAR intervention to the TAA, three models, namely healthy, aneurysm before treatment, and aneurysm after stent graft implantation models were built. These three models were presented and compared in terms of their flow patterns, time-averaged wall shear stress (TAWSS), oscillating shear index (OSI), and relative residence time (RRT). Reduced TAWSS and OSI with altered flow pattern were found on the aneurysm wall after the deployment of the microporous stent graft. Elevated RRT on the aneurysm sac indicated that red blood cells and platelets tended to stay longer in the aneurysm sac after implantation of the microporous stent graft. The alteration of flow patterns caused by the microporous stent graft revealed its potential to create a beneficial hemodynamic environment, which promotes platelet activation within the aneurysm and elicits localization of thrombus formation that ultimately lead to the recovery of an aortic aneurysm.