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. Key words: Stroke ;  Thrombosis ;  Models,animal ;