Clot Burden Score and Collateral Status and Their Impact on Functional Outcome in Acute Ischemic Stroke

Area of Science:

• Neurology
• Radiology
• Interventional Neuroradiology

Background:

• Thrombus length and collateral status are known predictors of functional outcome in acute ischemic stroke.
• The interaction between thrombus length and collateral circulation in influencing stroke outcomes requires further investigation.

Purpose of the Study:

• To investigate the individual and combined effects of thrombus length (clot burden score) and collateral status (FLAIR vascular hyperintensity score) on functional outcomes in acute ischemic stroke patients.
• To determine if collateral status modifies the association between thrombus length and functional outcome.

Main Methods:

• Pooled data from ASTER and THRACE trials for anterior circulation large-vessel occlusion stroke patients treated with endovascular thrombectomy.
• Assessed clot burden score and FLAIR vascular hyperintensity score on pre-treatment MR imaging.
• Used logistic regression to analyze the association and interaction between scores and favorable functional outcome (mRS 0-2 at 90 days).

Main Results:

• Favorable outcome was observed in 51% of 326 patients.
• Higher clot burden scores (smaller clots) and FLAIR scores (better collaterals) were associated with improved outcomes.
• The association between clot burden score and functional outcome was significantly stronger in patients with good collaterals (adjusted OR = 6.15).

Conclusions:

• The effect of thrombus length on functional outcome in acute ischemic stroke is influenced by collateral status.
• FLAIR vascular hyperintensity score is a valuable prognostic factor, particularly when contrast-based imaging is unavailable.