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Original research
Platelet-rich emboli are associated with von Willebrand factor levels and have poorer revascularization outcomes
  1. Andrew Douglas1,
  2. Seán Fitzgerald1,2,
  3. Oana Madalina Mereuta1,
  4. Rosanna Rossi1,
  5. Sean O'Leary1,
  6. Abhay Pandit1,
  7. Ray McCarthy3,
  8. Michael Gilvarry3,
  9. Lukas Holmegaard4,
  10. Margareta Abrahamsson4,
  11. Mikael Jerndal4,
  12. Niclas Dehlfors4,
  13. Paul Brennan5,
  14. Sarah Power5,
  15. Alan O'Hare5,
  16. Emma Griffin5,
  17. David F Kallmes2,
  18. Waleed Brinjikji2,6,
  19. István Szikora7,
  20. Turgut Tatlisumak8,9,
  21. Alexandros Rentzos4,
  22. John Thornton5,10,
  23. Karen Doyle1,11
  1. 1 CÚRAM, SFI Research Centre for Medical Devices, National University of Ireland Galway, Galway, Ireland
  2. 2 Department of Radiology, Mayo Clinic Rochester, Rochester, Minnesota, USA
  3. 3 Galway Neuro Technology Centre, Cerenovus, Galway, Ireland
  4. 4 Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
  5. 5 Interventional Neuroradiology Service, Department of Radiology, Beaumont Hospital, Dublin, Ireland
  6. 6 Department of Neurosurgery, Mayo Clinic Rochester, Rochester, Minnesota, USA
  7. 7 Department of Neurointerventions, National Institute of Neurosciences, Budapest, Hungary
  8. 8 Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden
  9. 9 Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, University of Gothenburg Sahlgrenska Academy, Gothenburg, Sweden
  10. 10 Royal College of Surgeons in Ireland, Dublin, Ireland
  11. 11 Department of Physiology, National University of Ireland Galway, Galway, Ireland
  1. Correspondence to Dr Karen Doyle, Physiology, CURAM, National University of Ireland Galway, Galway H91 TK33, Ireland; karen.doyle{at}


Background and aims Platelets and von Willebrand factor (vWF) are key factors in thrombosis and thus are likely key components of acute ischemic stroke (AIS) emboli. We aimed to characterize platelet and vWF levels in AIS emboli and to assess associations between their expression levels and clinical and procedural information.

Materials and method Histopathological and immunohistochemical analysis of emboli collected as part of the multi-institutional RESTORE registry was performed. The composition of the emboli was quantified using Orbit Image Analysis machine learning software. Correlations between clot components and clinical and procedural information were assessed using the χ2 test.

Results Ninety-one emboli samples retrieved from 63 patients were analyzed in the study. The mean platelet (CD42b) content of the clots was 33.9% and the mean vWF content of the clots was 29.8%. There was a positive correlation between platelet and vWF levels (ρ=0.564, p<0.001*, n=91). There was an inverse correlation between both platelets and vWF levels and percentage of red blood cells (RBCs) in the emboli (CD42b vs RBC: ρ=−0.535, p<0.001*, n=91; vWF vs RBC: ρ=−0.366, p<0.001*, n=91). Eighty-one percent of patients in the low platelet group had a good revascularization outcome (Thrombolysis in Cerebral Infarction 2c/3) compared with 58% in the high platelet group (χ2=5.856, p=0.016).

Conclusion Platelet and vWF levels in AIS emboli correlate with each other and both have an inverse relationship with RBC composition. Patients with platelet-rich clots have poorer revascularization outcomes.

  • stroke
  • platelets
  • thrombectomy

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  • AD and SF contributed equally.

  • Contributors AD, SF, and KD were involved in all stages of the manuscript from concept design to drafting the manuscript. LH, MA, MJ, ND, PB, SP, AO’H, EG, IS, TT, AR, and JT were responsible for collecting and recording the clinical and procedural information from patients. All authors reviewed, edited, and approved the final manuscript prior to submission.

  • Funding This work was supported by the European Regional Development Fund and Science Foundation Ireland (grant number 13/RC/2073).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available upon reasonable request.