Histologic differences between in situ and embolized carotid web thrombi: a case report

Abstract

Background The significance of carotid webs (CaWs) in ischemic stroke is becoming acknowledged. Histological features of clot composition in situ and secondary cerebrovascular embolized thrombi caused by CaW have not been described concurrently. Understanding clots’ histological composition is essential for understanding the pathophysiology of clot formation in CaW. Case presentation A 50-year-old male patient with acute ischemic stroke, which was believed to be caused by ipsilateral CaW, was admitted to the hospital. Mechanical thrombectomy was used to retrieve thromboemboli from the middle cerebral artery. One month thereafter, the patient underwent carotid endarterectomy, and in situ CaW thrombi were retrieved. Histological analysis by hematoxylin and eosin staining revealed that histopathologic embolized thrombi appeared as typical mixed thrombi, 46.03% fibrin/platelet ratio, 48.12% RBCs, and 5.85% white blood cells. In situ thrombi had a higher fibrin/platelet ratio (68.0%), fewer RBCs (17.2%), and 14.8% white blood cells. Conclusion The histopathology of large vessel occlusion stroke embolized thrombi by CaW is similar to that of other stroke etiologies. However, the clot composition of embolized thrombi significantly differs from that of in situ thrombi. CaW’s in situ thrombi showed predominantly fibrin, and embolized thrombi had equivalent contents of red blood cells and fibrin/platelets. Histopathological differences between in situ and embolized thrombi suggest new research directions for the etiology of embolization. Further studies are required to confirm these results.

Multimodality imaging of carotid web: A case report and literature review

“…18, 33, 34 But the superimposed thrombus had a fewer fibrin/platelet ratio and a higher red blood cells than Gao et al reported, which was the only previous study on histological diagnosis of thrombus superimposed in CW, to the best of our knowledge. 35…”

“…18,33,34 But the superimposed thrombus had a fewer fibrin/platelet ratio and a higher red blood cells than Gao et al reported, which was the only previous study on histological diagnosis of thrombus superimposed in CW, to the best of our knowledge. 35 This literature review identified 43 patients with asymptomatic CW who did not take any treatment. No ischemic events were associated with these asymptomatic CW, with a median follow-up time of 44.0 months.…”

Recurrent stroke shortly after mechanical thrombectomy secondary to carotid web: A case report

“…[ 4 , 24 ] Moreover, comparing histological features of clot composition in situ and secondary cerebrovascular embolized thrombi caused by CaW, it was found that the in situ thrombus showed mainly fibrin, and the embolized thrombus had the same content of red blood cells and fibrin/platelets. [ 25 , 26 ] Computational fluid dynamics studies using artificial models of CaW had shown blood flow disturbances. Studies have shown that thrombus formation at the CaW is associated with changes in the hemodynamic pattern.…”

Assessment of Complex Flow Patterns in Patients With Carotid Webs, Patients With Carotid Atherosclerosis, and Healthy Subjects Using 4D Flow MRI

“…Recent studies suggest that the composition of emboli forming due to CaW differs from other arterial clots 8–10 . In particular, CaW‐associated thrombi obtained after mechanical thrombectomy show a higher content of red blood cells on histological analysis 9–11 . Other arterial clots, such as those related to atherosclerosis, contain a higher percentage of platelets.…”

“…[8][9][10] In particular, CaW-associated thrombi obtained after mechanical thrombectomy show a higher content of red blood cells on histological analysis. [9][10][11] Other arterial clots, such as those related to atherosclerosis, contain a higher percentage of platelets. The shape of the CaWs induces alteration of blood flow leading to stagnation in the bulbar segment of the ICA.…”