Stent Porosity Efficiency in Treating Wide-Neck Saccular Renal Artery Aneurysm

Renal arteries are the arteries that supply blood to the kidneys. Renal arteries are the arteries that supply blood to the kidneys. Renal artery aneurysm (RAA) is the second most common visceral aneurysm to occur, which accounts for 22% of the visceral aneurysm. In general population, RAA rate of occurrence was only 0.1%. However, due to the extensive used of angiography technique, RAA has been discovered more frequently. Some claimed that the previous rate of incidence should be higher now because of the capability of angiography. The rupture of this aneurysm could result in haemorrhage, kidney lost and mortality. The size of the renal artery which is different compared to other types of arteries such as the abdominal aorta could produce different flow condition when the artery is inflicted with RAA condition. Thus, a thorough analysis is desired as RAA studies are very limited compared to other aneurysm conditions. In this study, the efficiency of the stent porosity was investigated in treating the RAA. Fluid-structure interaction (FSI) simulations and particle image velocimetry (PIV) experiments were the approaches taken to investigate the flow patterns of the blood when the stent of different porosities was placed in the aneurysm entrance. The effect of wall shear stress (WSS), the deformation of the artery and von Mises stress were also observed in determining the possibility of aneurysm rupture. The study found that the placement of stent of different porosities succeeds in providing an obstruction to the blood from circulating inside the aneurysm sac. This in turns reduced the WSS experienced by the aneurysm sac up a significant value of 96%. This reduction is crucial in order to prevent the aneurysm from rupture. Moreover, the placement of the stent provided support to the renal artery and preventing it from experiencing buckling failure. The maximum deformation of the artery reduced by 42% with stent was placed in the renal artery. In fact, the von Mises stress decreased below the threshold limit of 0.5 MPa with the presence of the stent. In addition, the study found that the stent of porosity 80% has a similar impact to the stent of lower porosity in the case of RAA at main renal artery.