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- Brinjikji, Waleed, et al.
(author)
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Endotheliitis and cytokine storm as a mechanism of clot formation in COVID-19 ischemic stroke patients: A histopathologic study of retrieved clots.
- 2023
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In: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - 2385-2011.
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Journal article (peer-reviewed)abstract
- Studies during the COVID-19 pandemic have demonstrated an association between COVID-19 virus infection and the development of acute ischemic stroke, particularly large vessel occlusion (LVO). Studying the characteristics and immunohistochemistry of retrieved stroke emboli during mechanical thrombectomy for LVO may offer insights into the pathogenesis of LVO in COVID-19 patients. We examined retrieved COVID-19 emboli from the STRIP, EXCELLENT, and RESTORE registries and compared their characteristics to a control group.We identified COVID-positive LVO patients from the STRIP, RESTORE, and EXCELLENT studies who underwent mechanical thrombectomy. These patients were matched to a control group controlling for stroke etiology based on Trial of Org 10172 in Acute Stroke Treatment criteria. All clots were stained with Martius Scarlet Blue (MSB) along with immunohistochemistry for interleukin-6 (IL-6), C-reactive protein (CRP), von Willebrand factor (vWF), CD66b, fibrinogen, and citrullinated Histone H3. Clot composition was compared between groups.Nineteen COVID-19-positive patients and 38 controls were included. COVID-19-positive patients had a significantly higher percentage of CRP and vWF. There was no difference in IL-6, fibrin, CD66b, or citrullinated Histone H3 between groups. Based on MSB staining, there was no statistically significant difference regarding the percentage of red blood cells, white blood cells, fibrin, and platelets.Our study found higher concentrations of CRP and vWF in retrieved clots of COVID-19-positive stroke patients compared to COVID-19-negative controls. These findings support the potential role of systemic inflammation as indicated by elevated CRP and endothelial injury as indicated by elevated vWF as precipitating factors in thrombus development in these patients.
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- Ospel, Johanna M., et al.
(author)
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What is a Challenging Clot? : A DELPHI Consensus Statement from the CLOTS 7.0 Summit
- 2023
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In: Clinical Neuroradiology. - 1869-1439 .- 1869-1447. ; 33:4, s. 1007-1016
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Journal article (peer-reviewed)abstract
- Background: Predicting a challenging clot when performing mechanical thrombectomy in acute stroke can be difficult. One reason for this difficulty is a lack of agreement on how to precisely define these clots. We explored the opinions of stroke thrombectomy and clot research experts regarding challenging clots, defined as difficult to recanalize clots by endovascular approaches, and clot/patient features that may be indicative of such clots. Methods: A modified DELPHI technique was used before and during the CLOTS 7.0 Summit, which included experts in thrombectomy and clot research from different specialties. The first round included open-ended questions and the second and final rounds each consisted of 30 closed-ended questions, 29 on various clinical and clot features, and 1 on number of passes before switching techniques. Consensus was defined as agreement ≥ 50%. Features with consensus and rated ≥ 3 out of 4 on the certainty scale were included in the definition of a challenging clot. Results: Three DELPHI rounds were performed. Panelists achieved consensus on 16/30 questions, of which 8 were rated 3 or 4 on the certainty scale, namely white-colored clots (mean certainty score 3.1), calcified clots under histology (3.7) and imaging (3.7), stiff clots (3.0), sticky/adherent clots (3.1), hard clots (3.1), difficult to pass clots (3.1) and clots that are resistant to pulling (3.0). Most panelists considered switching endovascular treatment (EVT) techniques after 2–3 unsuccessful attempts. Conclusion: This DELPHI consensus identified 8 distinct features of a challenging clot. The varying degree of certainty amongst the panelists emphasizes the need for more pragmatic studies to enable accurate a priori identification of such occlusions prior to EVT.
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