Hyperintense acute reperfusion marker (HARM) and thrombus analysis in acute ischemic stroke

Area of Science:

• Neurology
• Radiology
• Pathology

Background:

• Mechanical thrombectomy enables direct thrombus analysis in acute ischemic stroke.
• Hyperintense acute reperfusion marker (HARM) on FLAIR imaging signifies blood-brain barrier (BBB) disruption due to contrast extravasation.

Purpose of the Study:

• To investigate the association between the histopathological characteristics of retrieved thrombi and the presence of HARM in patients with acute ischemic stroke.

Main Methods:

• Analysis of 52 thrombi from 56 patients undergoing mechanical thrombectomy for acute ischemic stroke.
• Histopathological evaluation using H&E staining for fibrin and erythrocytes, and immunohistochemistry for inflammatory cells (CD3, CD20, CD45).
• Correlation of thrombus composition with HARM status and clinical outcomes (NIHSS, mRS).

Main Results:

• Worse clinical outcomes (NIHSS at 24h, mRS at 90 days) were observed in HARM-positive patients.
• Thrombi from HARM-positive patients showed a predominant composition of fibrin.
• These findings suggest a link between thrombus fibrin content and BBB integrity.

Conclusions:

• Fibrin-rich thrombi may be associated with BBB disruption, as indicated by HARM in acute ischemic stroke.
• Thrombus histopathology offers potential insights into stroke pathophysiology and BBB damage.
• Further research with detailed thrombus characterization and advanced imaging is warranted.