ABSTRACT NUMBER: ESOC2026A2020 COMPARISON OF HISTOLOGICAL COMPOSITION OF ACUTE ISCHEMIC STROKE (AIS) THROMBUS REMOVED BY ASPIRATION OR STENTRIEVER

Abstract Background and aims To investigate the association between mechanical thrombectomy and retrieved clot characteristics, we assessed the difference in histological composition of AIS clots retrieved by aspiration catheter and those retrieved by stentriever in single and multiple pass procedures. Methods We analysed 1013 clots collected per-pass from four hospitals in the RESTORE registry. The clots were stained with Martius Scarlet Blue, digital images were captured and main components (red blood cells, fibrin, platelet/other, white blood cells, collagen were quantified using Orbit Image analysis. The Wilcoxon rank sum test was used to assess statistically significant differences among the groups. Results 460 out of the 1013 cases analysed required a single pass for clot removal; in 553 cases, multiple passes were necessary. In single pass procedures, clots retrieved with stentriever were significantly poorer in red blood cells (RBC) (38% versus 52%, P<0.001) and richer in fibrin (33% versus 25%, P<0.001) than those retrieved with aspiration. In multiple pass procedures, we found differences in composition only for the first 3 passes, where clots retrieved with stentriever were significantly more fibrin-rich than those retrieved with aspiration, which were richer in RBCs. For clots retrieved after pass 4, no significant difference in composition was found between aspiration and stentriever removed clots. Conclusions Clots retrieved by stentrievers are richer in fibrin and those retrieved by aspiration are richer in RBCs. While a clear association is demonstrated, better understanding of device interaction and clot characteristics is needed to inform targeted thrombectomy device choice in the clinic. Conflict of interest Amanda Forde: nothing to disclose, Rosanna Rossi: nothing to disclose, Yingjuan Zhang: nothing to disclose, Emma Holian: nothing to disclose, Istvan Szikora: nothing to disclose, Klearchos Psychogios: nothing to disclose, Sarah Power: nothing to disclose, Katarina Jood: nothing to disclose, Alexandros Rentzos: nothing to disclose, Karen Doyle: nothing to disclose