Modeling Large Vessel Occlusion Stroke for the Evaluation of Endovascular Therapy According to Thrombus Composition

Figures

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  Figure 1. A simulation model for thrombectomy of in flow-injected human thrombi. (A) Overview of the EVIAS PlusTM System. (1) a plug-and-play station pump (2) an intracranial artery cartridge; (3) an aortic arch; (4) a thrombus injection system; (5) a distal thrombus filter (700 μm mesh); (6) fluid pressure monitoring outlet. (B) processed fluoroscopy imaging of one simulated endovascular therapy (EVT) showing baseline (1), immediately after in flow thrombus injection with M1 occlusion (red arrow) (2), after the stent-retriever deployment (3), during stent-retriever retrieval after proximal balloon inflation (red arrow) (4) and final control (5). SR, stent retriever.

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  Figure 2. Platelet-rich thrombi require more stent-retriever passes to achieve complete recanalization but release less distal emboli compared to RBC-rich thrombi. (A) Number of stent-retriever passes to achieve complete recanalization according to the thrombus composition (platelet and red blood cell (RBC)-rich thrombi). (B) Duration of the procedure to achieve complete recanalization. (C) Illustration of the distal thrombus filter with its removable mesh of 0.7 mm struts (left panel) and the illustration of the distal embolization score (right panel). (D) Distal embolization score according to the thrombus composition (a higher score indicating more distal emboli). *p < 0.05.

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  Figure 3. Histological aspect and organization of human thrombi causing large vessel occlusion (LVO) in the simulation station. (A) Representative image of a human RBC-rich clot before in flow injection (1) and after (2) its retrieval by EVT. (B) Macroscopic view in the stent retriever of the RBC-rich thrombus fragmented into two pieces (top panel) and a platelet-rich thrombus stuck in the aspiration catheter (panel at the bottom) (C) Representative H and E staining images of an RBC-rich (top) and platelet-rich (bottom) thrombus at the bottom showing: RBC-rich areas in red (*), fibrin/platelet-rich area in pink (arrows) and leukocytes in purple. Insets show higher magnification views of the squared areas. Bars = 100 μm.

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  Figure 4. Histological aspect of red blood cell-rich and platelet-rich thrombi before and after injection in the simulation system and EVT procedure. Representative images of hematoxylin and eosin (H and E) stained red blood cell (RBC)-rich (upper panels) and platelet-rich (middle panels) thrombi before being injected into the simulation system (left panels), and after their recovery by EVT (right panels). Insets show higher magnification images of the squared areas. Note that both types of retrieved thrombi are drastically compacted as shown by their reduced size and higher cell density as compared to initial thrombi. The lower panels show H and E images of the RBC-rich thrombus responsible for large vessel occlusion in the intracranial cartridge. Insets show higher magnification images of the squared areas. Note the compaction of thrombus components in both RBC-poor (upper inset) and RBC-rich (lower inset) areas.

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  Figure 5. Immunohistological aspects of retrieved thrombi causing LVO in the simulating system. Representative images showing platelets (CD42b, green), red blood cells (RBCs, yellow), fibrin (ogen) (magenta), and DNA (Hoechst 33,342, blue) staining in the core of a retrieved RBC-rich (upper panels) or platelet-rich (lower panels) thrombus. Note the stark contrast in fibrin structure between the platelet-rich (*, white asterisks) and RBC-rich (white arrowheads) areas in the inner core of the RBC-rich thrombus. Also worth noting is the accumulation of fibrin and platelets at the thrombus periphery as shown by the black arrowheads in the platelet-rich thrombus images. The black asterisks indicate the presence of uncondensed DNA, suggestive of neutrophil extracellular traps.