ABSTRACT NUMBER: ESOC2026A696 MULTIPLEX PROTEOMIC BIOMARKERS FOR ACUTE STROKE SUBTYPE DIFFERENTIATION: AN EXPLORATORY STUDY

Abstract Background and aims Rapid acute stroke triage remains challenging, particularly for early identification of intracerebral hemorrhage (ICH) and large-vessel-occlusion acute ischemic stroke (LVO-AIS). We assessed whether multiplex proteomics can identify biomarker signatures to improve early stroke subtype classification. Methods Exploratory analyses of a prospective cohort of suspected stroke participants presenting <24 hours from onset. Blood samples were collected upon emergency department arrival and plasma analyzed using the Olink Target 96 CVDIII proteomics panel. Differentially expressed proteins (DEPs) were identified for stroke (AIS+ICH) versus stroke mimics (SM) and across four diagnostic categories (LVO-AIS, non-LVO-AIS, ICH, SM) using non-parametric testing with false discovery rate correction (q<0.05). Multivariate LASSO regression with 10-fold cross-validation derived protein panels for binary classification tasks (stroke versus SM, ICH versus non-ICH, and LVO-AIS versus non-LVO). Results Among 175 participants (mean±SD age 71.2±15.7 years; median NIHSS (IQR) 10[4-19]), final diagnoses were 40 ICH, 82 AIS (46 LVO), and 53 SM. Stroke versus SM identified 19 DEPs (FDR<0.05), with strongest signals for NT-proBNP, Notch3, KLK6, MMP-2, and t-PA. Four-group analyses identified 10 significant DEPs (FDR<0.05) (Fig. 1). A LASSO-derived 24-protein panel discriminated stroke from SM with cross-validated AUC 0.68 (95%CI [0.65-0.75]). For ICH detection, a two-protein panel (KLK6, PLC) achieved AUC 0.80 (95%CI [0.75-0.86]). LVO versus non-LVO showed no meaningful discrimination (AUC 0.57(95%CI [0.53-0.62])). Conclusions Multiplex proteomics identifies blood-based signatures distinguishing stroke from SM and detecting ICH. The absence of distinct LVO-specific signatures highlights the need for complementary approaches for early LVO identification. Conflict of interest Julien Paul : nothing to disclose; Catherine Brassard : nothing to disclose; Ralph Nuhay : nothing to disclose; David Chiasson-Ricard : nothing to disclose; Gloria Ortega-Delgado : nothing to disclose; Nathalie Arbour: nothing to disclose; Laura C. Gioia : I declare having current funding from the Heart and Stroke Foundation of Canada. Figure 1 - belongs to Conclusions