Angiographic collateral status predicts functional outcome and early neurological deterioration in large-vessel occlusion stroke treated with endovascular therapy

 Why are you incompetently? predicting failure to recover than delivering recovery?

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Angiographic collateral status predicts functional outcome and early neurological deterioration in large-vessel occlusion stroke treated with endovascular therapy

Junying Li 1,2†

L

Lei Chen 1†

Z

Zhongjiao Lu 3

Y

Yanhui Li 2

Y

Yaling Wang 2



Lanying He 1

D

Dan Yang 1*

• 1. Department of Neurology, West China School of Medicine, Sichuan University, Sichuan University affiliated Chengdu Second People’s Hospital, Chengdu Second People’s Hospital, Chengdu, Sichuan, China

• 2. Bai Lian chi Community Health Center, Chengdu, Sichuan, China

Abstract

Background: 

Despite successful recanalization with endovascular treatment (EVT) for acute ischemic stroke (AIS), many patients experience poor outcomes. While collateral circulation is a known prognostic factor, its dynamic assessment via digital subtraction angiography (DSA) and its relationship to outcomes post-EVT require further investigation.

Methods: 

This single-center retrospective study analyzed 185 consecutive AIS patients with large vessel occlusion treated with EVT. Collateral status was graded on pre-treatment DSA using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale and categorized as poor, fair, or good. The primary outcome was functional independence (modified Rankin Scale [mRS] score 0–2) at 90 days. Secondary outcomes included early neurological deterioration (END) within 7 days and 90-day mortality.

Results: 

Patients with good collaterals had significantly higher rates of functional independence (66.1%) compared to those with fair (45.9%) and poor collaterals (13.2%). Conversely, the incidences of END (1.8% vs. 8.2% vs. 23.5%) and 90-day mortality (1.8% vs. 11.5% vs. 27.9%) were progressively higher in the good, fair, and poor collateral groups, respectively. Multivariable logistic regression confirmed that a higher collateral score was an independent predictor of good functional outcome and was independently associated with a lower risk of END and mortality.

Conclusion: 

DSA-assessed collateral status is a strong independent predictor of 90-day functional outcome, END, and mortality in AIS patients following EVT. Robust pretreatment collaterals are associated with markedly improved recovery and survival, highlighting the critical prognostic value of collateral assessment in guiding treatment and patient management.

Introduction

Endovascular treatment (EVT) is now established as the standard therapy for acute ischemic stroke (AIS) caused by large-vessel occlusion (LVO) within 24 h (1, 2), with multiple randomized trials demonstrating substantial reductions in disability and mortality (3). However, even after technically successful recanalization, nearly half of patients fail to achieve functional independence at 3 months (4). Notably, considerable outcome variability persists among patients with similar occlusion sites, baseline characteristics, and reperfusion success. This highlights the need for reliable, imaging-based biomarkers to refine treatment selection and improve prognostic precision in EVT population.

Collateral circulation is recognized as one of the most critical determinants of ischemic tissue fate (5, 6). Robust collaterals maintain residual perfusion to the penumbra, slow infarct progression, preserve metabolic viability, and enhance the likelihood of favorable neurological recovery (7, 8). Despite this recognized importance, the extent to which collateral integrity continues to influence outcomes after successful EVT remains incompletely understood. Existing studies have yielded conflicting results, with some demonstrating a strong association between good collaterals and improved outcomes (9, 10), while others reported no significant relationship (11, 12).

Emerging evidence further suggests that collateral status may modulate the time dependence of EVT efficacy. Patients with poor collaterals experience substantial declines in outcome with prolonged onset-to-reperfusion times, whereas those with robust collaterals show relative resistance to ischemic delay (13). Although collateral enhancement has been proposed as a therapeutic target, the clinical impact remains uncertain, partly due to heterogeneous collateral assessment methods and variable patient responses (14). Most prior studies have relied on computed tomography angiography (CTA) for collateral evaluation, where CTA-based grading has shown predictive value for post-EVT outcomes (15–17). However, CTA provides only a static snapshot of vascular filling, whereas digital subtraction angiography (DSA) offers dynamic, higher-resolution assessment of collateral flow. Despite these advantages, the prognostic implications of DSA-based collateral grading remain insufficiently explored. Existing evidence is limited, often restricted to either anterior or posterior circulation strokes, and prior studies have reported mixed findings regarding the strength and consistency of these associations (18, 19).

To address these knowledge gaps, the present study systematically evaluated the relationship between DSA-determined collateral status and short-term functional outcomes in AIS patients with LVO undergoing EVT. In addition, we examined the interaction between collateral status and reperfusion success, along with other clinical and imaging predictors of outcome. This work aims to clarify the prognostic value of angiographic collaterals and provide more precise insights into their role in EVT-treated AIS.