Brain atrophy and endovascular treatment effect in acute ischemic stroke: a secondary analysis of the MR CLEAN trial

 I could figure out nothing from this. Does EVT create brain atrophy? Or does existing brain atrophy change the success of EVT?

Brain atrophy and endovascular treatment effect in acute ischemic stroke: a secondary analysis of the MR CLEAN trial

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Sven PR Luijten, Kars CJ Compagne, Adriaan CGM van Es, ...

First Published October 28, 2021 Research Article 

https://doi.org/10.1177/17474930211054964

Article information

Abstract

Background

Brain atrophy is suggested to impair the potential for functional recovery after acute ischemic stroke. We assessed whether the effect of endovascular treatment is modified by brain atrophy in patients with acute ischemic stroke due to large vessel occlusion.

Methods

We used data from MR CLEAN, a multicenter trial including patients with acute ischemic stroke due to anterior circulation large vessel occlusion randomized to endovascular treatment plus medical care (intervention) versus medical care alone (control). We segmented total brain volume (TBV) and intracranial volume (ICV) on baseline non-contrast computed tomography (n = 410). Next, we determined the degree of atrophy as the proportion of brain volume in relation to head size (1 − TBV/ICV) × 100%, analyzed as continuous variable and in tertiles. The primary outcome was a shift towards better functional outcome on the modified Rankin Scale expressed as adjusted common odds ratio. Treatment effect modification was tested using an interaction term between brain atrophy (as continuous variable) and treatment allocation.

Results

We found that brain atrophy significantly modified the effect of endovascular treatment on functional outcome (P for interaction = 0.04). Endovascular treatment led to larger shifts towards better functional outcome in the higher compared to the lower range of atrophy (adjusted common odds ratio, 1.86 [95% CI: 0.97–3.56] in the lowest tertile vs. 1.97 [95% CI: 1.03–3.74] in the middle tertile vs. 3.15 [95% CI: 1.59–6.24] in the highest tertile).

Conclusion

Benefit of endovascular treatment is larger in the higher compared to the lower range of atrophy, demonstrating that advanced atrophy should not be used as an argument to withhold endovascular treatment.

Keywords

Ischemic stroke, acute stroke therapy, CT scan

Introduction

Benefit of endovascular treatment (EVT) for acute ischemic stroke (AIS) due to large vessel occlusion (LVO) in the anterior cerebral circulation has been demonstrated among a diverse variety of patient subgroups including older adults over age 80.¹ This group currently makes up 25% of the stroke population receiving EVT in daily clinical practice.² In these patients, brain atrophy is a common finding on diagnostic stroke imaging at hospital admission.³ Whether brain atrophy influences the effect of EVT, however, is undetermined.

Previous studies showed that in patients receiving EVT brain atrophy is independently associated with poor functional outcome,^4,5 but modification of the effect of EVT by brain atrophy in clinical controlled trials has not been reported. Given that the age distribution of EVT-eligible patients is shifting towards older ages^2,6 and will continue to do so over the next years due to aging of the population,^7,8 atrophy will be encountered more frequently.^9,10 This may be relevant for optimizing patient selection as brain atrophy may provide more individualized estimates of expected treatment benefit and clinical outcome as opposed to age.

Therefore, we investigated whether brain atrophy modifies the effect of EVT in patients with AIS due to LVO, and particularly, whether treatment benefit is uniform across the entire range of brain atrophy.