ABSTRACT NUMBER: ESOC2026A1711 HISTOPATHOLOGICAL AND PROTEOMIC CHARACTERIZATION OF MECHANICAL THROMBECTOMY RETRIEVED CLOTS IN ACUTE ISCHEMIC STROKE PATIENTS WITH LARGE VESSEL OCCLUSION

Abstract Background and aims Acute ischemic stroke (AIS) due to large vessel occlusion (LVO) remains a major cause of disability and mortality. Although mechanical thrombectomy (MT) has substantially improved recanalization rates, heterogeneity in thrombus composition may contribute to variability in procedural success and clinical outcomes. Increasing evidence suggests that macroscopic thrombus phenotype and molecular composition reflect stroke etiology and fibrinolytic resistance. Methods This observational, discovery-phase study aims to characterize the histopathological and proteomic features of thrombi retrieved during MT in AIS-LVO patients. The study plans to enrol 40 patients with cardioembolic and large artery atherosclerosis strokesubtypes, along with 40 age-, sex-, and risk-factor-matched healthy controls. To date, thrombi from 12 patients have been collected. The cohort has a mean age of 50.4±15.9 years, with 7 males and 5 females. Macroscopic assessment identified 7-red thrombi and 5-white thrombi, with a mean clot dimension of 0.29 × 0.21 × 0.15 cm. Retrieved thrombi are divided for histopathological analysis using hematoxylin and eosin staining and for proteomic profiling using liquid chromatography–tandem mass spectrometry (LC-MS/MS). Molecular findings will be correlated with thrombus phenotype, recanalization status, functional outcome assessed by the modified Rankin Scale, and haemorrhagic transformation. Results The study is designed to identify associations between macroscopic thrombus phenotype, histological architecture, and proteomic signatures across stroke subtypes. Preliminary data demonstrate the feasibility of standardized clot collection and downstream molecular analyses. Conclusions Integrated assessment of thrombus colour, size, histopathology, and proteomic composition may enhance understanding of clot biology in AIS-LVO and support the development of etiology-specific, precision-based therapeutic strategies. Conflict of interest Poorvi Tangri: nothing to disclose