| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 107 === Acute ischemic stroke, usually caused by sudden blood clot formation, could lead to fatal blockage in arteries with high mortality and morbidity. In recent times the mechanical thrombectomy devices have become increasingly involved in blood clot removal. The blood clot retriever, one kind of thrombectomy devices, is a nitinol self-expanding stent used to retrieve the blood clot. Currently, there are several kinds of blood clot retriever products on the market, but the designs of blood clot retrievers are not studied systematically. This research aims to evaluate the performance of blood clot retriever designs.
In this research, parametric design methodology was used in device design. Crown number and ring number, two of the design parameters, were treated as control variables and achieved six blood clot retriever design patterns. Finite element models were developed to analyze the mechanical behavior and the manufacturing feasibility of the devices. Then, the prototypes of blood clot retrievers would be produced. Finally, the in-vitro experiments were conducted to verify the effectiveness of these blood clot retrievers. Twenty-five quantitative experiments and five qualitative experiments were conducted with six blood clot retrievers in each of straight vessel and tortuous vessel. The in-vitro experiments results would be compared with finite element analysis results.
Results show that the effects of working length, radial stiffness, and deformation on effectiveness of blood clot retrievers are not obvious. In the straight vessel experiment, the ring number of design parameters affects the occurrence of clot disengagement and fragmentation, and the malapposition of blood clot retriever affects micro-fragmentation and blood residue. In the tortuous vessel experiment, the conformability of blood clot retriever is the crucial factor of effectiveness. In this research, a systematic study method for blood clot retriever was proposed, and the relationship between design parameters and effectiveness of blood clot retrievers were established. It is hoped that this research could provide a new direction for blood clot retriever development.
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