Stroke progression index as a dynamic metric is associated with functional outcome in progressive ischemic stroke with large vessel occlusion

Objective: Current evaluation of progressive ischemic stroke (PIS) with large vessel occlusion (LVO) relies on static clinical or imaging measures and lacks quantitative assessment of dynamic neurological deterioration. We proposed a novel metric, stroke progression index (SPI), to assess its association with clinical outcomes and benefit from endovascular treatment (EVT), and to explore its potential clinical relevance. Methods: We retrospectively enrolled consecutive LVO-PIS patients treated at our center between January 2022 and June 2025, limited to those with large-artery atherosclerosis. SPI was derived from National Institutes of Health Stroke Scale (NIHSS) change and progression time using a mathematically adjusted ratio. The primary endpoint was poor outcome at 90 days (mRS 3-6). We analyzed the association between SPI and outcomes, evaluated the effect of EVT, and explored relationships between SPI and disease course-related factors. Results: = 0.023). In treatment-effect analyses, lower SPI was associated with greater absolute benefit from EVT. Absolute risk reduction (ARR) was approximately 30% at SPI ≈11 and 10% at SPI ≈ 20. Exploratory analyses showed overall higher SPI in early than delayed progression, with poor outcomes being more common in patients with high SPI and poor collateral status. Conclusion: SPI is an independent prognostic risk factor in LVO-PIS that captures disease dynamics. The benefit of EVT varied across different SPI levels, suggesting that SPI may help inform clinical decision-making. These findings require further validation in larger, multicenter studies.