Hemodynamic Performance of Multilayer Stents in the Treatment of Aneurysms with a Branch Attached

Abstract

Although multilayer stents (MSs) can be used to treat aneurysm effectively, for some aneurysms with branches attached, the hemodynamic mechanisms are still unclear. In this work, we modeled five cases that involve 1–4-layer stents implanted in aneurysms with side branches, and the numerical approach was used. Case 1 corresponds to an aneurysm without a stent, and cases 2–5 represent 1–4-layer stents being employed within aneurysms, respectively. The results showed that the velocity within the sac declined dramatically and the eddies’ intensity weakened with increased number of stent layers, time-averaged wall shear stress (TAWSS), and nitric oxide production rate (TAR NO ) dropped linearly with increase in stent porosity, and oscillatory shear index (OSI) and relative residence time (RRT) increased evidently with MS intervention. Moreover, the MSs had a slight effect on the patency of the side branch; its flow rate was still above the normal case than without aneurysm. It can be concluded that MSs are helpful in promoting the growth of thrombus within the aneurysm through an isolated hemodynamic environment and keeping the branch unobstructed, but more clinical evidences are required.

Packing Technique with or without Remodeling for Endovascular Coil Embolization of Renal Artery Aneurysms: Safety, Efficacy and Mid-Term Outcomes

“…In one patient, we used a Leo intracranial stent, which is a nitinol self-expanding braided stent that is well suited for aneurysms on small tortuous arteries. Finally, stent grafts and flow diverters can be useful to preserve distal vascularization [ 16 , 17 , 18 , 19 ]. Initially, coronary stent grafts were used because of their high flexibility [ 43 ].…”

“…Nevertheless, the consistency of the data with a very high success rate and both recurrences successfully treated by endovascular techniques support this treatment method for patients with RAAs [ 52 ]. Few experimental in vitro and/or in vivo studies are reported regarding the use of numerical simulation and laboratory modelling to assess the different endovascular techniques available for the treatment of renal artery aneurysms [ 16 , 17 , 53 ]. Evaluation of functionality and biological response of those models would be of major interest and needs further studies.…”

“…More recently, flexible stent grafts and flow diverters have been introduced. Since their approval as an innovative stent system for peripheral aneurysm management, multilayer stents have been applied in several clinical cases [ 16 , 17 ]. The unique design of multilayer stents decreases mean velocity and vorticity within the aneurysm sac immediately and causes thrombus to form, resulting in physiological exclusion of the aneurysm from the circulation, whereas branches and collaterals sprouting from the aneurysm remain patent [ 17 ].…”

A systematic review and meta‐analysis of the performance of flow‐diverting stents in the treatment of peripheral and visceral artery aneurysms

“…Zhang et al observed a “special flow path” reserved inside the thrombosed aneurysm sac for the runoff of branches in such scenarios 16 . Other hemodynamic studies also demonstrated that the blood flow of collateral arteries was not compromised by the placement of FDS 29,30 …”

The hemodynamic effect of eccentricity in visceral branched aneurysms with multilayer stents

“…It is capable of remodeling vessel walls, initiating a self-healing thrombus formation and thereby degenerating aneurysm as well as allowing blood flow through its mesh, so we can reach a good compromise between TAAAs repair and the maintenance of patency in visceral vessels. [7][8][9] It has been documented that MS has become a promising therapeutic alternative for the repair of complex TAAAs cases due to its low-cost, off-the-shelf nature, compared to a custom-made chimney, fenestrated or branched EVAR. [10][11][12] Recently, many studies have engaged in uncovering the potential role of MS in aneurysm treatment.…”