In Silico Thrombectomy: A Validation with In Vitro Data
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Finite Element (FE) analyses are increasingly used to simulate and investigate key aspects of clinical procedures. A crucial requirement to their clinical relevance is validation. In this study, we focused on mechanical thrombectomy (MT), a minimally invasive treatment for acute ischemic stroke, aimed at removing an occluding clot from large cerebral vessels using stent-retrievers (SRs) and/or aspiration catheters (ACs). Ad hoc in vitro MT were performed in a silicone anatomical model, considering twelve different combinations of techniques (three), devices (two SRs and two ACs) and clot compositions. Ovine clot analogues containing 5% and 30% red blood cells (RBCs) in the blood mixture were employed [1]. First, the devices were mechanically tested and modelled in silico. Then, for each in vitro test, a corresponding FE analysis was performed [2], replicating the procedure as closely as possible. In silico and in vitro MTs were compared in terms of success/failure of clot removal and qualitatively in terms of clot fragmentation. The FE analyses successfully reproduced the in vitro outcomes in eight cases. In four of these, they were also able to reproduce the device-clot kinematics during the retrieval. The remaining four MT cases, involving aspiration and combined technique applied to highly fragmentable clots (30% RBCs), could not be fully reproduced with the adopted structural FE framework. Overall, the results demonstrated the capability of our FE analyses to reproduce the mechanical aspects of MT in a patient-like model. However, the inclusion of fluid-dynamic aspects would be necessary to more accurately and efficiently simulate aspiration-based procedures, especially when the clot is fragmented and totally ingested in the AC.
