Abstract|Stroke 3| Volume 357, SUPPLEMENT 1, e105, October 15, 2015

Thrombus histology and cryptogenic stroke — a different approach to determine etiology

      Objective: Ischemic stroke of undetermined cause is considered to be a major health issue and therefore recommended to be a top research focus in the field. Histopathological analysis of human “in-vivo”, mechanically extracted thrombi of patients with large vessel occlusion may contain additional “in-depth” information concerning the underlying pathology. Aim of this study was to elucidate the clinical problem of cryptogenic stroke by use of a multiparametric approach, analyzing histological, interventional and clinical outcome data of stroke patients.
      Methods: Thrombi of 145 consecutive patients with large vessel occlusion were collected during mechanical recanalization. The HE-stained specimen was analyzed concerning overall appearance and relative quantitative component fractions of erythrocytes, fibrin/thrombocytes and leucocytes. Detailed clinical and interventional data were obtained. Statistical analysis was performed searching for significant differences or pattern similarities in different stroke subtypes, defined by the international TOAST criteria. IRB and patient approval has been obtained.
      Results: In a consistent and conclusive overall pattern, arterio-embolic and TOAST 4 (mostly dissections) differ significantly from cardio-embolic and cryptogenic stroke subtype in histological parameters (e.g. lower erythrocyte fraction in cardio-embolic and cryptogenic groups, p = 0.038), interventional (e.g. higher number of maneuvers in cardio-embolic and cryptogenic groups, p = 0.012) and outcome (e.g. higher mRS in cardio-embolic and cryptogenic groups, p = 0.011) data. Cardio-embolic and cryptogenic subtype show matchable thrombus structure and similar clinical and interventional characteristics.
      Interpretation: The findings of this multiparametric approach strongly support the hypothesis of predominantly cardio-embolic mechanisms accounting for the majority of cryptogenic strokes.