Abstract WP152: Changes In Thrombus Fibrin Content By Time In Patients Undergoing Thrombectomy

Introduction: Understanding clot composition and associated genomic, epigenomic, and proteomic signatures could provide insight into thrombus biology and etiology, and aid in prognosis in stroke. We report preliminary analysis of histology evaluations in subjects enrolled in the INSIGHT Registry, a multicentered ‘multi-omic’ analysis of thrombi associated with acute hemorrhagic and ischemic stroke this multi-omic clot collection registry. Our aim was to determine potential histology differences in thrombi as a consequence of infarct time (time from last known normal to thrombectomy). Material and Methods: Subjects age ≥18 years, treated frontline with the Penumbra System for thrombectomy are included in this analysis. Patient demographics, medical history, radiographic, and procedural information are collected in conjunction with extracted clot and concurrent extracranial arterial blood. Enrollment, data collection, and data monitoring are ongoing for the INSIGHT registry. While the protocol includes analysis for proteomics and transcriptomics, for this analysis we used automated histology. An MSB Trichrome stain was used to evaluate the tissue. Composition was determined by automated pixel analysis, with the values representing ratios of the overall clot. Results: Samples from 60 subjects who were enrolled from 10 sites between 02/2021 and 07/2021. Analysis of the thrombi successfully determined the relative portions of fibrin, red blood cells (RBCs), and platelets (PLT). The median percentage of fibrin in the thrombi was 44.0% (IQR 29.0 - 57.6; N=60). The median time interval from Last Known Well to recanalization was 4.0 hours (IQR 2.9-12.8 hours; N=55). There was no correlation between the time interval of stroke and the percent of fibrin in the thrombus (Pearson correlation coefficient -0.01, p 0.94). Conclusion: These preliminary results demonstrate a lack of relationship between time interval of the stroke and clot histology composition with relation to fibrin. Thrombus fibrin composition is likely more related to other factors, and not predominantly related to time. We are currently investigating potential relationships to demographics and co-morbidities.