ABSTRACT NUMBER: ESOC2026A1779 FROM PENUMBRA TO CORE: NEUTROPHIL-TO-LYMPHOCYTE RATIO AS AN INDICATOR OF RAPID PROGRESSION IN ACUTE ISCHEMIC STROKE

Abstract Background and aims Systemic inflammatory indices have been associated with clinical outcomes in stroke. However, their relationship with the velocity of ischemic core expansion remains unclear. We investigated the association between systemic inflammatory markers and infarct growth rate (IGR) in patients with acute anterior large-vessel occlusion (LVO) ischemic stroke (IS). Methods We conducted a single-center retrospective observational study including consecutive patients admitted with acute anterior LVO IS, within 24 hours from known symptom onset, between January 2023 and August 2025. Ischemic core volume (CBF <30%) and IGR (core volume/onset-to-CT time) were calculated for each patient. Admission systemic inflammatory indices included: neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI). The primary outcome was the fast ischemic core progression, defined as IGR ≥10 mL/h. Secondary outcomes included continuous associations with IGR and relationships with ischemic progression phenotypes (slow, intermediate, fast). Results Among 120 patients included, 77 (64.2%) were classified as fast progressors. Admission NLR was independently associated with rapid ischemic core progression (OR 2.13; 95%CI 1.22–3.70; p = 0.007). Ordinal regression analysis confirmed that higher NLR (OR 1.90; 95%CI 1.19–3.03; p = 0.006) and PLR (OR 1.02; 95%CI 1.01–1.03; p = 0.050) were independently associated with faster ischemic progression phenotypes. In contrast, no significant association was observed between continuous NLR values and IGR. Conclusions Elevated admission NLR independently predicts faster ischemic core progression in anterior circulation LVO stroke, highlighting a pathophysiological link between systemic inflammation and accelerated infarct evolution. Conflict of interest Marco Andrighetti: nothing to disclose.