Abstract 139: Preclinical In-vivo Safety Evaluation Of Thrombectomy Devices In The Canine Cerebrovasculature

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Introduction: Thrombectomy devices have become an integral tool in the armamentarium of neuro-interventionalists to treat acute ischemic stroke (AIS). Previous preclinical evaluation of these devices has not assessed their safety in the native cerebrovasculature. We assessed the operation of stent-trievers in the canine basilar artery (BA), with a goal to evaluate their vascular safety on angiography and histopathology. Methods: Four mongrel canines (female, mean weight:12.53kg,n=2 each arm) were randomly assigned to receive the Solitaire FR Revascularization device (4mm X 22mm;eV3, Plymouth, MN) or the Enterprise VRD (4.5mm X 22mm ;Codman Neurovascular, Raynham, MA). The canine basilar artery (BA) was accessed through the anterior spinal artery (ASA, control vessel). The device was deployed in the basilar artery and withdrawn in the expanded state to the vertebrobasilar junction. The ASA, in which only the microcatheter was deployed, served as the control. Angiographic scoring of the vasospasm and histopathological assessment using a quantitative grading of the scanning electron microscopy (SEM) and cross-sectional hematoxylin and eosin histology was used to assess for the vascular integrity. Results: The Enterprise VRD and the Solitaire performed equally with grade 3 vasospasm on the first pass, which quickly resolved with intra-arterial Nicardipine administration and minimal vasospasm on subsequent passes. Based on the qualitative histopathological and SEM assessment the Solitaire and the Enterprise VRD device performed comparably when tracked through the canine basilar artery. Based on the luminal surface assessment from the SEM, the most likely damage expected from an intervention with either of these devices is expected to be partial damage to the internal elastic lamina and an exposure of the smooth muscle cells. Microcatheter navigation in the control vessels induced focal endothelial injury along the path in which the catheter was tracked. Conclusion: In an attempt to emergently re-vascularize the ischemic vascular territory, the vulnerability of the cerebrovasculature to manipulation by thrombectomy devices is often overlooked. Deployment of stent-trievers induces intimal damage that does not impact vessel integrity.