Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization

Abstract

Background Straightening of parent vessels happens for stent-assisted coiling embolization (SACE) treatment of intracranial aneurysms. This study aims to investigate aneurysmal hemodynamic modifications caused by stent-induced vessel straightening. Methods Stent and coil deployments of a SACE-treated distal bifurcation aneurysm by finite element method were performed first with the preoperative (not straightened, NS) and postoperative (straightened, S) vessel models respectively. Computational fluid dynamics were then performed for eight models, including (I) NS only model, (II) NS+stent model, (III) NS+coils model, (IV) NS+stent+coils model, (V) S only model, (VI) S+stent model, (VII) S+coils model, and (VIII) S+stent+coils model. Finally, changes in aneurysmal flow velocity, isovelocity surface and wall shear stress (WSS) were analyzed qualitatively and quantitatively. Results The flow was less in the S models than that in the corresponding NS models. Coils blocked most of the flow into the aneurysm sac in both NS models and S models and vessel straightening had more profound effect on the high aneurysmal flow volume reduction than coiling, while stenting generated adverse effect on flow reduction. Taking the NS only model as baseline (100%), the sac-averaged velocities of models II to VIII were 112%, 36%, 42%, 45%, 39%, 12%, 13%, and high flow volumes were 119%, 21%, 30%, 10%, 8%, 3%, 3%, while the sac-averaged WSSs were 106%, 37%, 44%, 41%, 35%, 17% and 24%, respectively. Conclusions Stent-induced vessel straightening combined coil embolization has the best performance in hemodynamic modifications and may reduce the recurrence rate, whereas stenting may generate adverse effect on hemodynamic alterations.

Procedural outcome following and Hemodynamic imaging analysis for anterior communicating artery wide-necked aneurysms by four different stents assisted coil embolization

“…Stents were initially used in EVT to prevent the coils from slipping out but were found in clinical trials to straighten the parent artery and cause a corresponding change in the aneurysm sac, thereby altering aneurysm hemodynamics [24]. In sidewall aneurysms, the use of stents has previously been shown to block the inflow of flow and thereby reduce the corresponding hemodynamics [25], but in bifurcation aneurysms, it has been argued that stents may produce a greater inertial force resulting from narrowed inflow jet, which enhances flow into the aneurysms [26].…”

How does the recurrence-related morphology characteristics of the Pcom aneurysms correlated with hemodynamics?

“…Kim et al ( 30 ) reported an outer curve aneurysm with lower vascular tortuosity was more similar to a bifurcation aneurysm and more likely to recur. Leng et al ( 31 ) and Wan et al ( 32 ) both pointed out that better hemodynamic changes can be achieved by using stents to straighten blood vessels. The risk of recurrence can be reduced by weakening the hemodynamic characteristics of bifurcation aneurysms, which was also consistent with our research.…”

Hemodynamic Effects of Stent-Induced Straightening of Parent Artery vs. Stent Struts for Intracranial Bifurcation Aneurysms

“…In the end, the surface-based aneurysm and vessel geometry model with the 3D representation of the stent were used for the subsequent CFD analysis. The exact method can be referenced in our previous study ( 7 ). The FEM simulations matched the actual stent-deployment images, including the parent artery straightening ( Figure 2 ).…”

“…However, the stent has a scaffold function and can induce angular deformation of parent arteries in the intracranial bifurcation aneurysms (2)(3)(4). It can migrate the flow impingement away from the aneurysm neck to decrease recurrence (5)(6)(7). Meanwhile, a stent with its mesh has a flow diverter effect by reducing the WSS and velocity of the aneurysm sac (8).…”