新型可转换型腔静脉滤器作用机理及实验研究

The intervention of vena cava filter (VCF) as a foreign body will bring the corresponding complications in human body, such as the bleeding at the puncture part, hematoma, inferior vena cava obstruction, thrombosis at the puncture part, the filter shift and the injury of inferior vena cava problems. The new convertible vena cava filter was proposed at this paper, The methodology that combined technology of theoretical analysis with experimental research were used to test the filter mechanism and the effects on blood flow, which have laid a more scientific foundation for researching the new filter. The filter of deformation mechanism and mechanical properties was researched by Finite Element Method (FEM) which was used to analyze the main factors of deformation behavior, supporting stiffness, fatigue strength, In order to make clear the stress distribution of the main bearing parts of the filter in the process of conversion bracket and reveal the regular impact that the vena cava filters injury bring. The fluid-structure interaction model has been set up, Computational Fluid Dynamics (CFD) was used to simulate the hemodynamic under the condition of physiology, thereby, the distribution of parameters such as flow, pressure, wall shear stress were obtained and the blood flow dynamic problems were explored in different lesion type in treatment. Finally, By doing the animal experiment, imaging and pathologic examination of the vena cava were reviewed, Hyperplasia and damage in vena cava were observed, the blood clots, shifts and drops of the filter were analyzed, the safety and effectiveness of the filter were evaluated. The research results of the new convertible vena cava filters will have the theory significance and clinical application value.

腔静脉滤器作为异物置入，在人体内也会带来相应的并发症，比如有穿刺部位出血、血肿、下腔静脉阻塞、穿刺部位血栓形成、滤器移位以及下腔静脉损伤等问题。本研究提出一种新型可转换型腔静脉滤器，利用理论分析与实验研究相结合的技术，分析滤器作用机理及对血流的影响，为新型滤器的研发奠定理论基础。利用有限元法，通过对滤器变形机理和力学性能的研究，分析影响变形行为、支撑刚度、疲劳强度等的主要因素，明确滤器在转换支架过程中的主要承载部位，揭示滤器对腔静脉损伤的影响规律。建立滤器流固耦合模型，利用计算流体动力学方法模拟生理条件下的血流动力学，获得流场、压力、壁面切应力等参数的分布情况，探索不同病变型式在治疗中的血流动力学问题。实施动物实验，进行腔静脉造影复查和病理检查，观察腔静脉内膜增生和损伤情况，分析滤器内血栓，滤器移位或脱落等，评估滤器的安全性和有效性。可转换型腔静脉滤器的研究成果具有理论意义和临床应用前景。

腔静脉滤器作为异物置入，在人体内也会带来相应的并发症，比如有穿刺部位出血、血肿、下腔静脉阻塞、穿刺部位血栓形成、滤器移位以及下腔静脉损伤等问题。本研究提出一种新型可转换型腔静脉滤器，利用理论分析与实验研究相结合的技术，分析滤器作用机理及对血流的影响，为新型滤器的研发奠定理论基础。(1)提出适合血管和滤器耦合扩张的有限元分析方法，模拟分析了滤器变形行为和置入过程，揭示滤器类型和结构参数对其生物力学性能的影响规律，明确滤器在变形过程中的主要承载部位及作用机理，讨探了滤器植入对血管壁的损伤机制及安全性，为新型滤器的设计和研发提供了科学的参考。(2)建立滤器流固耦合模型，利用计算流体动力学方法对腔静脉滤器血流流场进行分析，获得血流流速、出入口压差和壁面剪应力等参数，揭示了滤器的结构参数和释放方式对血流流速、血压压差、过滤杆上的切应力的影响规律，为新型滤器的临床应用奠定了理论基础。(3)为明确腔静脉滤器在不同条件下的过滤血栓效果，利用计算流体力学方法，对各种腔静脉滤器在不同的血栓含量和血栓直径下进行了血流动力学数值模拟。研究发现，滤器的植入造成了血流动力学的改变，它的过滤效果不仅与过滤单元结构和参数有关，还与血栓含量和血栓直径大小有着密切相关。(4)经理论分析和实验研究发现，新型腔静脉滤器对血流的干扰较小，尤其对小直径血栓具有较好的过滤效果，且导致血栓形成的低壁面剪应力区域非常小，捕捉血栓效果优于目前上市的Denali和Aegisy滤器。(5)通过动物实验，对置入滤器的腔静脉进行造影复查和病理检查，观察腔静脉内膜增生和损伤情况，分析滤器内血栓，滤器移位或脱落等。结果显示，新型滤器释放简便、安全、容易掌握，6头猪体内释放滤器均获得成功，无穿孔、移位和断裂等严重并发症问题。滤器置入28天后内膜完整覆盖，但仍较薄，都可以取出，结构安全可靠，该研究成果具有理论意义和临床应用前景。