Mediation of Multiphase Collateral Status on Functional Outcome by ASPECTS-Based Net Water Uptake in Acute Stroke

Background and Purposes

The Alberta Stroke Program Early CT Score-based net water uptake (ASPECTS-NWU) is a quantitative imaging biomarker used to assess early ischemic changes in acute ischemic stroke patients. ASPECTS-NWU has been investigated in identifying stroke onset time, measuring ischemic tissue edema, and predicting functional outcomes. However, the mediating effect of ASPECTS-NWU and its association with collaterals, infarct volume, and functional outcome still need to be explored. Therefore, we hypothesized that ASPECTS-NWU is a mediator between collateral circulation and infarct volume and investigated their association with outcome.

Methods

There were 201 patients, and 131 of them underwent mechanical thrombectomy. Collaterals were graded using the multiphase Menon score. The mediating effect of ASPECTS-NWU between collaterals and infarct volume was investigated. The association between infarct volume, collaterals, recanalization status, and functional outcome was assessed by univariable and multivariate logistic regression analysis.

Results

Patients with good collaterals displayed higher ASPECTS, lower ASPECTS-NWU, lower National Institute of Health Stroke Scale score at admission (NIHSS_admission), and smaller infarct volume, ischemic tissue volume, and penumbra volume. ASPECTS-NWU was a mediator between collaterals and infarct volume, and the contribution rate of the mediator was 27.9%. In multivariate logistic regression analysis, infarct volume and recanalization status were associated with functional outcomes.

Conclusions

ASPECTS-NWU was a mediator and played a partial role between collaterals and infarct volume. Infarct volume and recanalization status were strong predictors of functional outcome. ASPECTS-NWU and collaterals indirectly influenced functional outcomes by regulating infarct volume.