Mechanism of Action and Biology of Flow Diverters in the Treatment of Intracranial Aneurysms

Ravindran, Krishnan; Casabella, Amanda M.; Cebral, Juan R.; Brinjikji, Waleed; Kallmes, David F.; Kadirvel, R

doi:10.1093/neuros/nyz324

Cited by 79 publications

(54 citation statements)

References 62 publications

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“…21,22 Immediately after the device is placed, endothelialization gradually progresses from the side of the parent artery to the aneurysm neck. 23,24 In particular, endothelialization of the aneurysm neck requires adhesion of smooth muscle cells to the neck to form a scaffold.…”

Section: Discussionmentioning

confidence: 99%

Outcome of flow diverter placement for intracranial aneurysm with dual antiplatelet therapy and oral anticoagulant therapy

et al. 2020

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Purpose Antiplatelet therapy initiated before flow diverter placement is effective for the prevention of ischemic complications. However, the effectiveness of oral anticoagulant treatment is unclear. This retrospective study evaluated the complications and obliteration rates after flow diverter placement in patients taking anticoagulants. Methods A total of 155 cases were treated by Pipeline Flex placement for unruptured large and giant cerebral aneurysms in our hospital between October 2015 and June 2019. The groups of 8 patients taking anticoagulants before operation and 147 patients not taking anticoagulants were compared. Results Clopidogrel oral dose ( P = 0.002) was significantly lower in the anticoagulant group. Delayed aneurysm rupture ( P = 0.002) and additional treatment ( P = 0.009) rates were significantly higher and complete obliteration rate ( P = 0.011) was lower in the anticoagulant group. Conclusions Additional oral anticoagulant administration before flow diverter placement does not reduce ischemic complications compared to dual antiplatelet therapy, but does increase hemorrhagic complications, especially delayed aneurysm rupture. Complete obliteration of the cerebral aneurysm is difficult to achieve in patients taking anticoagulants.

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Section: Discussionmentioning

confidence: 99%

Outcome of flow diverter placement for intracranial aneurysm with dual antiplatelet therapy and oral anticoagulant therapy

et al. 2020

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“…We focused on the flow diversion efficacy of the PED stent and techniques used to improve the local stent porosity, e.g., the push-pull technique 41 , or wall apposition were not considered. A porosity of 70% at the neck is reported to be optimal for aneurysm occlusion 42,43 . This is not achievable in practice due to oversizing, device deformation, manipulation or aneurysm location 40,42 .…”

Section: Methodsmentioning

confidence: 99%

In-silico trial of intracranial flow diverters replicates and expands insights from conventional clinical trials

et al. 2021

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The cost of clinical trials is ever-increasing. In-silico trials rely on virtual populations and interventions simulated using patient-specific models and may offer a solution to lower these costs. We present the flow diverter performance assessment (FD-PASS) in-silico trial, which models the treatment of intracranial aneurysms in 164 virtual patients with 82 distinct anatomies with a flow-diverting stent, using computational fluid dynamics to quantify post-treatment flow reduction. The predicted FD-PASS flow-diversion success rates replicate the values previously reported in three clinical trials. The in-silico approach allows broader investigation of factors associated with insufficient flow reduction than feasible in a conventional trial. Our findings demonstrate that in-silico trials of endovascular medical devices can: (i) replicate findings of conventional clinical trials, and (ii) perform virtual experiments and sub-group analyses that are difficult or impossible in conventional trials to discover new insights on treatment failure, e.g. in the presence of side-branches or hypertension.

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“…Recently, FDs have been widely used for the treatment of cerebral aneurysms (10,11). The effectiveness of FDs for large and giant thrombosed aneurysms has been reported, with curative thrombosis of the aneurysm sac caused by reducing flow, without the use of coils (12). Posterior circulation thrombosed aneurysms are particularly difficult to treat because of the high rate of recanalization and compression of the brainstem, which coil embolization has the potential risk of worsening (13,14).…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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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.

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Mechanism of Action and Biology of Flow Diverters in the Treatment of Intracranial Aneurysms

Cited by 79 publications

References 62 publications

Outcome of flow diverter placement for intracranial aneurysm with dual antiplatelet therapy and oral anticoagulant therapy

Outcome of flow diverter placement for intracranial aneurysm with dual antiplatelet therapy and oral anticoagulant therapy

In-silico trial of intracranial flow diverters replicates and expands insights from conventional clinical trials

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

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