Collateral grade of the Willis' circle predicts outcomes of acute intracranial internal carotid artery occlusion before thrombectomy.

Hongchen Zhao,Baolin Wang,Ganggang Xu,Yi Dong,Qiang Dong,Wenjie Cao

doi:10.1002/brb3.1452

Abstract

Background and PurposeEndovascular mechanical thrombectomy (EVMT) shows significant promise in improving acute ischemic stroke (AIS) with proximal artery occlusion, but outcomes have been variable. We explored the patients treated by thrombectomy to investigate the association between a favorable clinical outcome of EVMT in intracranial internal carotid artery occlusion (iICAO) and a set of predictors.MethodsA total of 38 iICAO patients treated by EVMTs were analyzed. Primary collateral grades (PCG) at baseline based on the integrity of Willis' circle were categorized into three degrees. The favorable outcomes, measured by modified Rankin scale (mRS), were defined as ≤2 at 90 days. The reperfusion was one of the most important confounders, defined as modified thrombolysis in cerebral infarction (mTICI) ≥ 2b. The other risk factors included demographic characteristics, vascular risk factors, stroke severity, procedural EVMT, and PCG at baseline was adjusted to reveal the association with favorable outcomes.ResultsOf 38 iICAO patients, 65.8% (25 in 38) achieved reperfusion. However, only 31.6% (12/38) achieved favorable outcomes at 90 days. With a PCG3, 61.5% of them achieved favorable outcomes, while only 37.5% of those with PCG2 and PCG1 achieved favorable outcomes (p = .003). In multivariable logistic regression, PCG was revealed as a predictor for favorable outcomes (OR 5.278, p = .019) after adjusting the reperfusion and other factors.ConclusionsThe PCG based on the integrity of Willis' circle might be an underlying predictor of the prognosis of AIS in patients with iICAO after EVMT. The function of intact anterior communicating artery (AcoA) and ipsilateral posterior communicating artery (PcoA) in favoring prognosis of the iICAO patients might need to be validation in future study.

Highlights

Endovascular mechanical thrombectomy (EVMT) is proven benefit in patients with acute ischemic stroke (AIS) with anterior circulation large vessel occlusion
In the SWIFT PRIME trial (Jadhav et al, 2017), MR CLEAN trial (Berkhemer et al, 2016) and ESCAPE trial (Goyal et al, 2015), pial collateral status according to CTA, were found to positively relate with favorable functional outcomes of AIS with anterior circulation LVO
We established a strategy to evaluate the integrity of Willis' circle by categorizing it into primary collateral grades (PCG) in AIS patients with intracranial internal carotid artery occlusion (iICAO) and investigated the association between Primary collateral grades (PCG) and prognosis in patients treated with EVMT

Summary

| INTRODUCTION

Endovascular mechanical thrombectomy (EVMT) is proven benefit in patients with acute ischemic stroke (AIS) with anterior circulation large vessel occlusion. Several factors, including National Institutes of Health Stroke scale (NIHSS) onset, occlusion type and occlusion level, have been reported to be associated with favorable functional outcomes, while others, such as poor initial status, unsuc‐ cessful recanalization, cardioembolism, and supraclinoid‐terminal occlusion, are associated with poor outcomes of AIS with internal carotid artery occlusion (Kwak et al, 2014). Collateral is another important factor that may potentially impact prognosis. We established a strategy to evaluate the integrity of Willis' circle by categorizing it into primary collateral grades (PCG) in AIS patients with iICAO and investigated the association between PCG and prognosis in patients treated with EVMT

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