In Vitro Assessment of Vascular Injury following Stent Retriever Retraction in Clinically Relevant Endothelialized Silicone Models

Custom neurovascular silicone geometries, vessel models, and device assessment. Geometries were first created in CAD (A), with the pilot study (top) utilizing the same tortuous neurovascular pathway previously published,¹³ while main study A (middle) and main study B (bottom) each incorporated new geometries relevant to stent retriever use in the cerebral vasculature. Dimensions, ranging from 5.5 mm proximal ends to 1.5 mm distal ends, are noted on the computer models. Silicone models were fabricated based on these custom geometries, then sterilized and coated with fibronectin. Coated silicone models were placed in bioreactor systems (B) before human umbilical vein endothelial cell deposition. Vessels were then cultivated on peristaltic pumps in a large incubator for 3–4 days before device treatment (C). On the day of treatment, stent retrievers were inserted into endothelialized silicone vessels, deployed and retracted, then harvested for evaluation (D). After retraction through the vessels (top), they were analyzed by using H&E imaging, which revealed the expected cobblestone morphology of endothelial cells in untreated controls (middle) and endothelial denudation from stent retriever induced injury (bottom).

Main study A evaluation of Trevo ProVue NXT (3 × 32 mm, 4 × 41 mm, 6 × 37 mm) and Solitaire X (6 × 40 mm) stent retriever-induced endothelial injury after 1- or 2-pass treatment. Endothelial injury ranged from <3% surface area injured in control vessels to approximately 50%–70% surface area injured in the 2-pass treatment groups (A). In the main study A geometry, results from 3 regions of interest, identified as A4, A5, and A6 in the labeled diagram, illustrated that higher injury was most often observed in the distal narrow region of the vessels (B).