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Abstract
Introduction One of challenges in mechanical thrombectomy is tortuous anatomy of the vessels. New-generation stent retrievers with segmented design offer the possibility of improving the efficacy of clot removal in tortuous anatomy. The aim of this study is to assess how vessel tortuosity affect the efficacy of the stent retrievers and evaluate the efficacy of the newer-generation stent retrievers with segmented design.
Materials and methods Vascular silicone models with three levels of tortuosity were created. Tortuosity of the mild, moderate and severe model was 41.9, 53.5 and 85.6, respectively, which was semiautomatically measured using an open source package, Better Skeletonization working in MATLAB. An elastic and cohesive clot was produced by mixing whole porcine blood, bovine fibrinogen and thrombin. A segment of clot was delivered by the flow to the MCA lying from M1 distal and M2 proximal. Each stent-retriever (2 second-generation stent-retriever, Trevo XP and Solitaire FR as well as 2 newer stent retrievers with segmented design, Embotrap and Versi Retriever) was deployed over the clot through a microcatheter and retrieved with clot into an intermediate catheter with continuous aspiration. Clot retrieval was scored as success if the clot was removed without migration or visible fragmentation. Comparisons between stent retriever type and severity of tortuosity on thrombectomy success were made using two-way ANOVA. Afterwards, comparisons between stent retriever types within severity tortuosity on outcome were made using one-way ANOVA.
Results Mechanical thrombectomy with each stent retriever was repeated 5 times in the mild tortuous model and 10 times in the moderate and severe model (figure 1). In general, both the stent retriever type (p<0.01) and the severity of the vessel tortuosity (p<0.001) affect the success rate in a significant way. Post-hoc tests showed that severe tortuosity led to significantly worse outcomes than mild or moderate tortuosity (p<0.001). The Versi stent retriever led to significantly better outcomes than the Solitaire (p<0.001) and Trevo stent retrievers (p<0.05). The Embotrap also resulted in higher success rates than the Solitaire and Trevo stent retrievers, although there was no statistically significant difference.
Conclusions Tortuosity affects successful rates of mechanical thrombectomy. In this experimental model, mechanical thrombectomy with newer stent retrievers with segmented design resulted in higher success rates compared with second-generation stent retrievers.
Disclosures N. Kaneko: 2; C; NeuroVasc Technologies. Y. Komuro: None. H. Yokota: None. S. Tateshima: 2; C; NeuroVasc Technologies. 4; C; NeuroVasc Technologies.