Histopathological Composition of Thrombus in Acute Ischemic Stroke May Vary Even Within the Same Patient: A Preliminary Study Examining Clots According to Their Area of Retrieval.

Objective: Mechanical thrombectomy enables histopathological examination of clots in patients who have suffered acute ischemic strokes. Many studies have described about the relationship between the histopathological compositions of retrieved thrombi and imaging findings, clinical outcomes, and stroke etiology without consensus. In this study, we examined the histological composition of thrombi according to their retrieval site and methods. Methods: We divided retrieved clots into three parts (those retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter) and then histopathologically analyzed their compositions by measuring the area occupied by red blood cells (RBCs), fibrin/platelets (F/Ps), and white blood cells (WBCs). Results: Each specimen showed various composition even within the same patient. For example, the area occupied by RBCs was 20.9% ± 12.1%, 30.5% ± 13.5%, and 41.3% ± 16.1% in the clot retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter, respectively. Conclusion: Histopathological clot composition may vary even within the patient. Further research is needed to investigate more objective methods of histopathological analysis and their clinical significance.