High-Fidelity Modeling and in Vitro Validation of a Novel NiTi Stent Retriever

Purpose Nickel–titanium (NiTi) stent retrievers leverage superelasticity to navigate tortuous vascular anatomies, yet their intricate geometries pose significant challenges for accurate finite element (FE) modeling. This study evaluates the influence of mesh type and design representation on the predictive fidelity of FE simulations for a novel NiTi stent retriever. Methods NiTi tube properties for a novel stent retriever prototype were characterized. FE models were developed using tetrahedral and hexahedral solid elements, as well as beam elements with alternative junction representations. Lateral compression, axial tension, and bending simulations were validated against experiments. The selected beam formulation was then incorporated into a full-process model of crimping, delivery, deployment, and retrieval, with in vitro validation in straight, L-shaped, and U-shaped glass vessel models. Results The hexahedral solid model showed the closest agreement with device-level experiments and most clearly resolved local stress and strain concentrations. Among the beam formulations, the T-type junction model preserved the primary load-transfer path and provided an efficient representation for full-process simulations. After interface calibration, the full-process model reproduced deployment configuration, retrieval-force evolution, and procedure-dependent deformation. In the U-shaped model, the predicted mean retrieval force differed from the experiment by 2.1%, and peak axial strain remained below 8%. Conclusion The discretization strategy affected both device-level mechanical prediction and procedure-level retrieval response. The mechanically validated and interface-calibrated beam model provides an efficient framework for simulating NiTi stent retriever procedures in rigid in vitro vessel models. The identified interface coefficient may serve as a reference for similar NiTi–glass retrieval simulations.