The preparation and evaluation of thrombus model used for acute ischemic stroke

Objective: To prepare a new thrombus model by fluid model method, which is suitable for evaluation of mechanical thrombectomy devices for acute stroke. Methods: The fluid model adopted the Chandler loop theory, while the static model adopted conventional method. Mechanical properties of thrombi prepared by fluid model and static model were measured by manual elongation test (15 samples in each group) and catheter injection test (15 samples in each group). Histological structure was compared among the above thrombus models (5 samples in each group) and specimens of five patients with stroke by hematoxylin-eosin staining method. Then, thrombi in fluid model were utilized to establish embolization of vessels in swine model (two pigs) for evaluation of radiopacity. Independent-Sample test was performed to compare the maximum tensile length of two methods, and Fisher's exact test was used to compare the rate of thrombus fragmentation after catheter injection test. Results: The maximum tensile length of two models were (4.28 ± 0.23) and (3.16 ± 0.13) cm, respectively, and the difference was statistically significant (t = 16.38, P < 0.01); After catheter injection, the fracture rates of thrombus were 13% (2/15) and 60% (9/15), which were also statistically significant (P < 0.05). As to histological structure, thrombi prepared by fluid model showed mixed thrombus structure, which similar to thrombi of stroke patients, But thrombi prepared by static model were replete with erythrocytes under the microscope. A total of eight vessels (lingual arteries and superficial cervical arteries) in two swines were successfully occlusive (TIMI 0 or 1), and sufficient radiopacity of each injected thrombus was observed. Conclusions: The thrombi prepared by fluid model not only have good mechanical stability and sufficient radiopacity, but their histological structure is similar to thromboemboli retrieved from cerebral arteries of patients with acute stroke. (authors)