Hemodynamics Beyond Ischemic Zone Underlies Early Neurological Deterioration in Minor Stroke with Large Vessel Occlusion.

Early neurological deterioration (END) occurs in a substantial proportion of minor stroke patients with large vessel occlusion or severe stenosis (LVO/SS) and is a strong predictor of poor outcome, yet its underlying mechanisms remain debated. The cerebral blood volume (CBV) index is defined as the ratio of the mean CBV in the hypoperfusion (Tmax>6s) region to the mean CBV in the normal brain tissue, incorporating hemodynamics beyond the ischemic zone into its calculation. In this multicenter retrospective study, we evaluated the predictive value and pathophysiological implications of CBV index for END in patients with anterior circulation LVO/SS and mild symptoms. Among 401 eligible patients, END occurred in 21.7%. Stepwise logistic regression analysis revealed that higher CBV index was independently associated with END (adjusted OR [95% CI]: 3.85 [1.14, 12.96], p = 0.030). Mediation analysis revealed that 27.9% of the effect of CBV index on END was explained by increased hypoperfusion volume (indirect effect: 0.06, 95% CI: [0.02, 0.11], p = 0.007). These findings indicate that although a higher CBV index reflects favorable baseline collaterals, it may also indicate insufficient hemodynamic reserve and vulnerability to hypoperfusion progression, potentially facilitating extension of ischemia and subsequent END.