Abstract Number: Esoc2026a1479 Infarct Core Growth Rate Predicts Outcome in Intracranial Atherosclerotic Disease

Abstract Background and aims Large vessel occlusion (LVO) acute ischemic stroke due to intracranial atherosclerotic disease (ICAD) may experience better clinical outcomes compared to non-ICAD-LVO patients. This study aimed to assess the impact of core growth rate (CGR) on the relationship between ICAD and stroke outcomes. Methods We analysed LVO patients who received endovascular thrombectomy (EVT) from the International Stroke Perfusion Imaging Registry (INSPIRE). ICAD was defined by the presence of residual stenosis in the target intracranial artery following successful EVT. CGR was calculated as acute core volume divided by the time from stroke onset to CT Perfusion, dichotomised into slow-CGR (≤5mL/hr) vs. non-slow-CGR (5mL/hr). Causal mediation analysis was used to evaluate the relationship between CGR and ICAD on poor outcomes (mRS 5–6 at 3-month). Results 1056 patients were included: 247 ICAD and 809 non-ICAD. The ICAD group had a lower rate of poor outcomes (17% vs. 32%, p0.001), and a higher prevalence of slow-CGR (78% vs. 47%, p0.001) compared to non-ICAD group. Mediation analysis revealed that ICAD decreased the probability of poor outcome by 15% (unadjusted), with slow-CGR accounting for 34% of this total effect. After adjusting for age, sex, baseline-NIHSS, ICA-occlusion, collateral, hypertension, diabetes, and thrombolysis, ICAD still reduced the probability of poor outcome by 13% (total effect=-0.13, 95% CI-0.20, -0.07, p0.001), with slow-CGR mediating 27% of this effect (natural-indirect-effect=-0.04, 95% CI-0.7, -0.01, p=0.023). Conclusions ICAD patients have slower core growth rate and better outcomes. Slow-CGR is a key mechanism accounting for better outcomes in ICAD patients. Conflict of interest Yueming Wang, Chushuang Chen, Mark William Parsons, Carlos Garcia-Esperon, Gang Li, Jian Wu, and Longting Lin: nothing to disclose.