O03 Developing an electrical impedance sensor to identify platelet content in acute ischemic stroke clots: results from the ex vivo clotbase international registry

<h3>Introduction</h3> Development of a medical device that uses an electrical impedance signature to identify clot characteristics that influence success of treatment could improve stroke patient outcomes. <h3>Aim of Study</h3> To assess how well electrical impedance platelet signature identified platelet composition of acute ischemic stroke (AIS) clots, which may be negatively associated with successful first-pass effect. <h3>Methods</h3> Blood clots from 423 patients were analysed in the Clotbase International Registry. Impedance measurements were taken following clot retrieval by thrombectomy. Clot samples were fixed in formalin, paraffin-embedded and platelet composition quantified with anti-CD42b antibody in 3 μm sections using immunohistochemistry. Expression was quantified using Orbit Image Analysis and correlated with impedance estimation. Spearman’s correlation coefficient was calculated using a training set of 305 clots. Mann-Whitney U-test assessed statistically significant differences between groups. <h3>Results</h3> Impedance-based platelet estimations correlated well with the platelet content determined by CD42b immunohistochemistry, with a slope of 0.6 and Spearman’s correlation of r=0.5 (p&lt;0.0001). In 221 cases, clot was removed successfully in 1 pass with mTICI 2c or better (FPE). FPE was not achieved in 202 cases (including mTICI 0-2b and clot requiring &gt;1 pass). Platelet content was significantly lower in FPE than non-FPE cases as assessed using histology (p=0.02) and impedance signature (p=0.04). <h3>Conclusion</h3> Electrical impedance estimation of platelet content in AIS clots is consistent with histological findings. Further work will continue to improve the specificity of the impedance signature, advancing development of a medical device that could guide clinical decision making in the stroke acute care setting. <b>Acknowledgments</b>: SFI CÚRAM: 13/RC/2073_P2, SENSOME. <h3>Disclosure of Interest</h3> no.