Posterior circulation collateral flow modifies the effect of thrombectomy on outcome in acute basilar artery occlusion

So what are you doing about this to still assure 100% recovery for these patients? 

Posterior circulation collateral flow modifies the effect of thrombectomy on outcome in acute basilar artery occlusion

Gabriel Broockshttps://orcid.org/0000-0002-7575-98501, Tobias D Faizyhttps://orcid.org/0000-0002-1631-20201, Lukas Meyer1, Maximilian Groffmann1, Sarah Elsayed1, Helge Kniep1, Fabian Flottmannhttps://orcid.org/0000-0001-8358-80891, Matthias Bechsteinhttps://orcid.org/0000-0002-5652-74991, Thilo Rusche2,3, Gerhard Schön4, Jawed Nawabihttps://orcid.org/0000-0002-1137-06435, Peter Sporns2, Jens Fiehler1, Andre Kemmling6,7, and Uta Hanning1
 

Background

In basilar artery occlusion stroke, the impact of the collateral circulation on infarct progression in the context of endovascular treatment is yet poorly studied.
 

Aim

 

This study investigates the impact of the posterior circulation collateral score (PCCS) on functional outcome according to the extent of early ischemic changes and treatment. We hypothesized that the presence of collaterals, quantified by the PCCS, mediates the effect of endovascular treatment on functional outcome in patients with acute basilar artery occlusion.
 

Methods

 

In this multicenter observational study, patients with basilar artery occlusion and admission computed tomography were analyzed. At baseline, Posterior circulation Acute Stroke Prognosis Early Computed Tomography score (pcASPECTS) was assessed and PCCS was quantified using an established 10-point grading system. Logistic regression analyses were performed to identify factors associated with good functional outcome (modified Rankin Scale scores 0–2 at day 90).
 

Results

 

A total of 151 patients were included, of which 112 patients (74%) underwent endovascular treatment. In patients with a better PCCS (>5), the rate of good outcome was significantly higher (55% vs. 11%; p = 0.001). After adjusting for PCCS, vessel recanalization was significantly associated with improved functional outcome (aOR: 4.53, 95%CI: 1.25–16.4, p = 0.02), while there was no association between recanalization status and outcome in univariable analysis. Patients with low pcASPECTS generally showed very poor outcomes (mean modified Rankin Scale score 5.3, 95%CI: 4.9–5.8).
 

Conclusion

 

PCCS modified the effect of recanalization on functional outcome, particularly in patients with less pronounced ischemic changes in admission computed tomography. These results should be validated to improve patient selection for endovascular treatment in basilar artery occlusion, particularly in uncertain indications, or to triage patients at risk for very poor outcomes.
Keywords
Computed tomography, stroke, thrombectomy, ischemia, infarction
1Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2Department of Neuroradiology, Universitätsspital Basel, Basel, Switzerland
3Department of Clinical Radiology, University of Münster, Münster, Germany
4Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
5Department of Radiology, Charité University Medical Center, Berlin, Germany
6Department of Neuroradiology, University of Marburg, Marburg, Germany
7Department of Neuroradiology, University Medical Center Schleswig-Holstein, Lübeck, Germany
Corresponding author(s):
Gabriel Broocks, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. Email: g.broocks@uke.de

Introduction

The impact of mechanical thrombectomy (MT) on functional outcome in acute ischemic stroke patients with anterior circulation large vessel occlusion is well-established.1,2 For patients with basilar artery occlusion (BAO), evidence is yet sparse, although this population represents approximately 20% of all ischemic strokes.2–6 Recently, published results of randomized controlled trials suffered from loss of clinical equipoise and failed to prove the superiority of endovascular treatment (EVT) in this population.7 Nevertheless, BAO is associated with high rates of mortality and poor functional outcome. Timely neuroimaging triage is required not only to select patients for EVT but also to detect severe complications, such as malignant infarction potentially causing brain stem damage.8,9 The neurological assessment in the cohort of BAO stroke can be challenging due to the high variety of symptoms.10 Lastly, imaging-based evaluation of posterior circulation stroke extent is also relevant to timely recognize complications that require decompressive surgery.11–13 The importance of the collateral status in anterior circulation stroke has been demonstrated thoroughly.14–16 Here, collaterals have been proposed to modify the effect of EVT and its assessment is part of routine admission imaging, and it is even utilized in randomized trials to select patients for MT.15,17–20 In contrast, presence of posterior circulation collaterals in BAO patients is a feature that is yet far from being regularly used in clinical practice. Its impact on the development of malignant cerebellar edema, and its effect on the response to MT is yet unknown.4
The posterior collateral circulation score (PCCS) has been introduced as a semiquantitative 10-point grading system in computed tomography angiography (CTA) and has been associated with functional outcome following posterior circulation stroke. The purpose of this study was to investigate the impact of the PCCS on functional outcome in the context of MT, and particularly analyze how PCCS mediates the effect of MT on functional outcome, depending on early ischemic changes assessed using Posterior circulation Acute Stroke Prognosis Early CT score (pcASPECTS). We hypothesized that PCCS is a mediator of functional outcome in BAO patients undergoing MT.