Computer Modeling of Clot Retrieval-Circle of Willis.

Thanh G Phan,Matthew Sinnott,Velandai Srikanth,Richard Beare,Henry Ma,James Hilton,Mayank Goyal

doi:10.3389/fneur.2020.00773

Abstract

Endovascular clot retrieval, often referred to as mechanical thrombectomy, has transformed the treatment of patients with ischemic stroke based on an underlying large cerebral vessel occlusion, ranging from the extracranial internal carotid artery (ICA) to the M1 (proximal) segment of the middle cerebral artery (MCA). The aim of this study was to evaluate the effect of a progressive occlusion of the extracranial portion of the ICA on the cerebral blood flow either with a conventional guiding catheter or a balloon-guiding catheter, which enables the operator to completely occlude the parent artery by inflating the balloon around the tip of this type of guiding catheter. We evaluated the impact of flow reduction in the ICA in the setting of ipsilateral MCA occlusion given the different configurations of the circle of Willis (CoW). The computer model of cerebral arteries was based on anatomical works by Rhoton (1) and van der Eecken (2). The interactive experimental results are available on the web at https://gntem3.shinyapps.io/ecrsim. In the setting of left MCA occlusion, compensation from the anterior and posterior communicating artery preserved the flow in the left anterior cerebral artery (ACA) but not the left MCA branches. Under selected CoW configurations, such as classic, missing Acom, or missing A1 segment of the ACA and concurrent right ICA occlusion, there was a progressive decrease of flow in the left ACA to a minimum of 78% when the simulated catheter fully occluded the left ICA. Flow collapsed (<10%) in the left ACA and MCA branches under CoW configurations, such as bilateral fetal PCA. In summary, compensatory flow collapsed under certain clot retrieval scenarios and unusual configurations of CoW.

Highlights

Endovascular clot retrieval (ECR) or mechanical thrombectomy transformed treatment of patients with large vessel occlusion (LVO) [3,4,5,6,7,8]
We have utilized the capability of a computer model of the cerebral arteries to explore the effect of advancing a catheter for clot retrieval under different hypothetical LVO scenarios
The simulations show that, under selected configurations of circle of Willis (CoW), there is potential for a collapse of cerebral blood flow

Summary

Introduction

Endovascular clot retrieval (ECR) or mechanical thrombectomy transformed treatment of patients with large vessel occlusion (LVO) [3,4,5,6,7,8]. Patients with LVO involving the internal carotid artery (ICA) and middle cerebral artery (MCA) or combined lesions have been successfully treated in these trials. There are still several unanswered questions with clot retrieval: safety of advancing catheter along ICA in setting of ipsilateral MCA occlusion, given the concomitant occlusion of Computer Modeling of Clot Retrieval the contralateral ICA. In this setting, there is a hypothetical possibility that the cross-flow across anterior communicating artery (Acom) and the partial protection provided by leptomeningeal anastomoses (LAs) would be insufficient. This study uses a computer model, based on the anatomical works of Rhoton [1] and van der Eecken [2], which was created in our earlier work [9]

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Conclusion