title: Thrombus composition in acute ischemic stroke: a histopathological study of thrombus extracted by endovascular retrieval.
abstract: OBJECTIVE
  The composition of occlusive thrombus in acute ischemic stroke may affect treatment success. Neuroimaging characteristics may correlate with thrombus composition. In this study we aimed to investigate the relationship between the hyperdense artery sign (HAS) on imaging and thrombus composition.
  
  
  METHODS
  Acute ischemic stroke patients who underwent endovascular thrombus retrieval from 2010-2012 were prospectively recruited. One blinded pathologist prepared the histology sections of retrieved thrombi whereby staining with haematoxylin and eosin and CD34 immunostain were performed. Histology sections were categorised into 4 phases of thrombus formation: red blood cell (RBC) dominant, RBC proportion equal to fibrin, fibrin dominant and organised fibrin. Computed tomography (CT) brain scans were assessed for HAS. Fisher's exact test was performed to identify an association between HAS and thrombus composition.
  
  
  RESULTS
  Forty patients were included. The mean age was 65.6±12.9 years and 67.5% were male. Atrial fibrillation was detected in 19 (47.5%) patients, diabetes mellitus in 6 (15.0%), hypercholesterolaemia in 11 (27.5%), hypertension in 20 (50.0%) and previous stroke or transient ischemic attack in 8 (20.0%) patients. Of the retrieved thrombi, 11 (27.5%) were RBC dominant, 11 (27.5%) RBC proportion was equal to fibrin, 7 (17.5%) fibrin dominant and 11 (27.5%) organised fibrin pathology. HAS was present in 29 (72.5%) patients and was significantly associated with thrombus early phase pathology (P<0.05).
  
  
  CONCLUSIONS
  HAS was significantly associated with early phase thrombus composition. This may enable the prediction of thrombus composition and allow for targeted selection of therapeutic modality.
authors.affiliation: Melbourne Brain Centre, Level 4, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
authors.forename: Natasha
authors.initials: N
authors.lastname: Simons
authors.affiliation: Neurointervention Service, Department of Radiology, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Mitchell
authors.affiliation: Neurointervention Service, Department of Radiology, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Dowling
authors.affiliation: Department of Histopathology, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Gonzales
authors.affiliation: Melbourne Brain Centre, Level 4, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia; Neurointervention Service, Department of Radiology, Royal Melbourne Hospital, Parkville, Victoria 3050, Australia. Electronic address: bernard.yan@mh.org.au.
authors.forename: Bernard
authors.initials: B
authors.lastname: Yan
mesh_terms: D000368:Aged; D001706:Biopsy; D057510:Endovascular Procedures / Q000379:methods; D005260:Female; D006801:Humans; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D008297:Male; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D017131:Thrombectomy / Q000379:methods*; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000473:pathology*
keywords: Ischaemia; Stroke; Thrombolysis; Thrombus; Thrombus retrieval