Introduction 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.

Aim of Study 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.

Methods 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.

Results 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<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 >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).

Conclusion 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.

Acknowledgments: SFI CÚRAM: 13/RC/2073_P2, SENSOME.

Disclosure of Interest no.