Abstract Number ‐ 35: Maximum Euclidean Deflection‐A Novel Metric For Safety Of Neurovascular Devices

Abstract

Introduction Endovascular thrombectomy (EVT) devices are evolving rapidly to improve safety and efficacy of EVT‐mediated recanalization of large vessel occlusion strokes, and to access medium and distal vessel occlusions. To enable effective comparative analyses, there is a need to develop an objective in‐vitro safety metric for new EVT devices. Methods We utilized three FDA‐approved stent‐retrievers (4 mm diameter; variable lengths) currently available in the United States and deployed them in an in‐vitro ischemic stroke bench model (Sim Agility, Mentice Inc., Sweden). The stent‐retrievers were deployed in the M1 segment of the middle cerebral artery of the model using a system comprised of an 0.014 inch guide wire and 0.021 inch microcatheter. After unsheathing in the M1 segment, in the absence of a blood clot, the microcatheter was withdrawn back into the petrous internal carotid artery, and the whole system was withdrawn as a rate of 5 mm per second. Maximum deflection of the terminal internal carotid was measured in 3 axes using a specialized camera set‐up. Results A total of 3 passes were performed for each stent‐retriever (stent A, stent B, and stent C). Maximum deflection of the terminal internal carotid artery (from resting position to largest displacement during stent‐retrieval withdrawal) was measured in 3 planes and the values were as follows (Table).Maximum Euclidean Deflection (MED) ranged from 6.1 to 9.1 mm. Deflection varied based on 3 stent‐retriever designs and the plane of measurement. Figure demonstrates deflections as seen in Stent A. Conclusions Withdrawing an unsheathed stent‐retriever from the middle cerebral artery leads to significant deflection of the internal carotid artery terminus in an in‐vitro stroke model. The degree of deflection is variable in different planes and varies based on stent‐retriever design. Further studies are required to examine the predictors and impact of the deflection.