Toward a novel stent retriever: design, optimization and experimental validation

Acute ischemic stroke remains a leading cause of global disability and mortality. While mechanical thrombectomy with stent retrievers has improved outcomes through rapid reperfusion, the main limitation is the lack of conformability in tortuous and bifurcated arteries, thus reducing the thrombus retention efficacy in such complex vascular anatomies. This study introduces a novel self-expandable stent retriever design featuring a segmented closed-cell structure with bridging elements, designed to enhance both radial force and flexibility. Finite element analysis evaluated mechanical performance under different loading configurations, aiming at assessing a few key biomechanical parameters such as maximum principal strain and radial force. Then, a multi-objective optimization was performed to increase the device radial force while maintaining low strains. Compared to commercial devices, the optimized stent demonstrated a 18.2% lower bending moment and maintained cross-sectional geometry more effectively under deformation, indicating improved flexibility and shape preservation during navigation in tortuous vessels. Preliminary proof-of-concept in vitro thrombectomy experiments demonstrated effective engagement with mechanically stiff thrombi in different realistic scenarios, such as in stenotic and curved vessel models. While retrieval in bifurcated models still presents some challenges, the results suggest that the proposed design offers a promising balance between flexibility and radial strength, potentially improving thrombectomy outcomes in complex vascular environments.