Per-pass analysis of acute ischemic stroke clots: Impact of stroke etiology on extracted clot area and histological composition

Seán Fitzgerald, Rosanna Rossi, Oana Madalina Mereuta, Duaa Jabrah, Adaobi Okolo, Andrew Douglas, Sara Molina Gil, Abhay Pandit, Ray McCarthy, Michael Gilvarry, Dennis Dunker, Annika Nordanstig, Erik Ceder, Petra Redfors, Katarina Jood, Niclas Dehlfors, Georgios Magoufis, Georgios Tsivgoulis, Waleed Brinjikji, David F. KallmesAlan O'Hare, Sarah Power, Paul Brennan, Jack Alderson, András Nagy, Ágnes Vadász, Klearchos Psychogios, Istvan Szikora, Turgut Tatlisumak, Alexandros Rentzos, John Thornton, Karen M. Doyle

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background Initial studies investigating correlations between stroke etiology and clot composition are conflicting and do not account for clot size as determined by area. Radiological studies have shown that cardioembolic strokes are associated with shorter clot lengths and lower clot burden than non-cardioembolic clots. Objective To report the relationship between stroke etiology, extracted clot area, and histological composition at each procedural pass. Methods As part of the multi-institutional RESTORE Registry, the Martius Scarlett Blue stained histological composition and extracted clot area of 612 per-pass clots retrieved from 441 patients during mechanical thrombectomy procedures were quantified. Correlations with clinical and procedural details were investigated. Results Clot composition varied significantly with procedural passes; clots retrieved in earlier passes had higher red blood cell content (H4=11.644, p=0.020) and larger extracted clot area (H4=10.730, p=0.030). Later passes were associated with significantly higher fibrin (H4=12.935, p=0.012) and platelets/other (H4=15.977, p=0.003) content and smaller extracted clot area. Large artery atherosclerotic (LAA) clots were significantly larger in the extracted clot area and more red blood cell-rich than other etiologies in passes 1-3. Cardioembolic and cryptogenic clots had similar histological composition and extracted clot area across all procedural passes. Conclusion LAA clots are larger and associated with a large red blood cell-rich extracted clot area, suggesting soft thrombus material. Cardioembolic clots are smaller in the extracted clot area, consistent in composition and area across passes, and have higher fibrin and platelets/other content than LAA clots, making them stiffer clots. The per-pass histological composition and extracted clot area of cryptogenic clots are similar to those of cardioembolic clots, suggesting similar formation mechanisms.

Original languageEnglish (US)
Pages (from-to)1111-1116
Number of pages6
JournalJournal of neurointerventional surgery
Issue number12
StatePublished - 2021


  • atherosclerosis
  • intervention
  • stroke
  • thrombectomy

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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