ORIGINAL RESEARCH article
Front. Neurol.
Sec. Stroke
HYPERINTENSE ACUTE REPERFUSION MARKER (HARM) AND THROMBUS ANALYSIS IN ACUTE ISCHEMIC STROKE
Sena Aksoy 1,2
Ibrahim Kulac 3
Hatem Hakan SELÇUK 4
Batuhan KARA 4
Ali Burak KIZILIRMAK 5
Bayram Yilmaz 6,7
Yasemin Gürsoy-Özdemir 3
Atay Vural 3
Aysun SOYSAL 2,1
1. Istanbul Aydin Universitesi VM Medical Park Florya Hastanesi, Istanbul, Türkiye
2. Istanbul Bakirkoy Prof Dr Mazhar Osman Ruh Sagligi ve Sinir Hastaliklari Egitim ve Arastirma Hastanesi, Istanbul, Türkiye
3. Koc Universitesi Tip Fakultesi, Istanbul, Türkiye
4. TC Saglik Bakanligi Bakirkoy Dr Sadi Konuk Egitim ve Arastirma Hastanesi, Bakırköy, Türkiye
5. Koc Universitesi, Istanbul, Türkiye
6. Yeditepe Universitesi Tip Fakultesi, Istanbul, Türkiye
7. Dokuz Eylul Universitesi, Alsancak, Türkiye
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Abstract
Mechanical thrombectomy allows thrombus analysis in acute ischemic stroke. The extravasation of contrast material in the cerebrospinal fluid (CSF) in Fluid-attenuated inversion recovery (FLAIR) imaging is named as hyperintense acute reperfusion marker (HARM), which is an indicator of deterioration in the blood-brain barrier (BBB). In this study, it was aimed to examine the relationship between histopathological features of thrombus and HARM in acute ischemic stroke. A total of 56 patients who underwent mechanical thrombectomy (MT) were included in the study. Procedural data such as the number of passes, technique employed, and recanalization scores based on the modified Thrombolysis in Cerebral Infarction (mTICI) score were documented. FLAIR imaging was performed 24 hours after contrast administration. The presence of contrast extravasation into the cerebral sulci was defined as a positive HARM. 52 thrombi were successfully retrieved and analyzed. Thrombus sections were stained with hematoxylin and eosin (H&E) to evaluate fibrin and erythrocyte composition. Immunohistochemical staining with CD3, CD20 and CD45 antibodies was conducted to identify T lymphocytes, B lymphocytes, and total leukocytes, respectively. In our study, it was found that clinical outcomes—measured by National Institutes of Health Stroke Scale (NIHSS) scores at 24 hours and modified Rankin Scale (mRS) scores at 90 days— were significantly worse in HARM-positive patients. Histopathological analysis revealed that thrombi from HARM-positive patients were predominantly rich in fibrin, suggesting a potential association between thrombus composition and BBB disruption. Future studies incorporating more detailed thrombus characterization alongside advanced radiological markers may yield valuable insights into stroke pathophysiology.
Summary
Keywords
Acute ischemic stroke, Blood-Brain Barrier, Hyperintense acute reperfusion marker, Mechanical thrombectomy, thrombus analysis
Received
11 October 2025
Accepted
16 February 2026
Copyright
© 2026 Aksoy, Kulac, SELÇUK, KARA, KIZILIRMAK, Yilmaz, Gürsoy-Özdemir, Vural and SOYSAL. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Sena Aksoy
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