Possibility of Worsening Flow Diversion Effect Due to Morphological Changes of a Stented Artery With Multiple Overlapping Stents for Partially Thrombosed Vertebral Artery Aneurysms

Abstract

Background: Morphological changes of a stented artery can cause a flow diversion effect to reduce intra-aneurysmal flow; however, there is a potential for the negative effect of increased intra-aneurysmal flow. We present cases with multiple overlapping stents for a partially thrombosed vertebral artery aneurysm and characterize the hemodynamic properties of a recurrent case by focusing on the morphological changes of the stented artery.Methods: Between October 2017 and April 2019, four consecutive cases of symptomatic unruptured large and giant partially thrombosed vertebral artery aneurysms were treated with multiple overlapping low-profile visualized intraluminal support stents and no coils. Both angiographic and clinical outcomes were assessed. Computational fluid dynamics analysis was performed to clarify hemodynamic features. The degree of pressure elevation was calculated as the pressure difference (Pd). Wall shear stress (WSS) was also calculated.Results: In three of the four cases, successful flow reduction was achieved with no morphological change of the stented arteries. The patients' symptoms were gradually improved. The remaining case required additional stents after the initial treatment. In the recurrent case, Pd was noticeably elevated at the aneurysm neck after treatment, and WSS was generally increased in the area due to altered blood flow into the aneurysm dome caused by morphological changes of the stented artery.Conclusion: Overlapping stents can be used for the treatment of large and giant thrombosed vertebral artery aneurysms with flow diversion effect; however, morphological changes of the stented artery requires careful attention as it may lead to an increase in the intra-aneurysmal flow, causing negative outcomes.

Progressive volume reduction and long-term aneurysmal collapse following flow diversion treatment of giant and symptomatic cerebral aneurysms

“…Similar findings and expectations have been suggested by Carneiro et al, according to their experience with FD and extremely large and giant intracranial aneurysms ( 35 ). Transient sac increase after flow-diversion for giant aneurysms is a well-recognized scenario ( 17 , 27 , 36 , 37 ). Post-treatment, substantial aneurysmal enlargement in our cohort occurred in nine patients.…”

Flow Redirection Endoluminal Device Flow Diverter Placement for Recurrent Dolichoectatic Vertebrobasilar Artery Aneurysm Treated with Multiple Low-Profile Visualized Intraluminal Support Stents: A Case Study

“…Suzuki et al reported on the possibility of worsening flow diverting effects due to morphological changes in vessels with overlapping stents placed for partially thrombosed vertebral artery aneurysms using computational fluid dynamics analysis. 23) Similarly in the present case, the overlapping stents may have worsened the flow diverter effect in the vessel, resulting in residual leakage of the contrast medium outside the stent.…”

Therapeutic dilemmas regarding giant aneurysms of the intracranial vertebral artery causing medulla oblongata compression

“…A total of 45 articles containing 53 patients (53 aneurysms) were identified. 3–47 In addition to the 53 patients identified in the literature, we also included two typical cases for illustration which were not included in the final analysis (Figures 2, 3 and 4).…”

“…Giant aneurysms of the intracranial VA are rare intracranial lesions, and only 53 reported cases were identified in this review. 3–47 The intracranial segment of the VA runs along the anterolateral aspect of the medulla oblongata. Aneurysms originating from the intracranial segment of VA are rare and often dissecting aneurysms, 48 and most of them are stable and do not rupture.…”