- 學位論文
經導管人工主動脈瓣之設計與模擬
Design and Simulation of Transcatheter Aortic Prosthetic Valves
摘要
心臟瓣膜疾病為瓣膜因老化、感染、天生缺陷或鈣化等異常表現，導致患者心臟的血液輸送量下降，影響運動或日常生活、造成暈眩或昏厥，甚至引起其他種類心臟疾病。由於心臟瓣膜疾病和年齡有顯著相關，年長者罹患心臟瓣膜疾病的比率越高。隨著高齡社會全球化，心臟瓣膜疾病也變得普遍。 心臟瓣膜主要治療手段為更換人工心臟瓣膜，而目前主流的選擇之一就是經導管人工心臟瓣膜。和傳統開心手術比較，經導管人工心臟瓣膜最大的優勢在於快速簡單的手術過程，和小創口恢復快的導管手術。然而這項技術在近十年內才獲得 FDA 許可，目前市面上經導管人工心臟瓣膜的選擇很也少。有鑑於此，本研究針對人工心臟瓣膜進行更多元的設計，藉由模擬分析與流場實證，探討自擴張人工心臟瓣膜的設計與臨床性質之關聯。相較於較短壽命的商業用生物性瓣膜，本研究重於較少被討論的人工材質瓣膜，期望能延長瓣膜的使用壽命。 本研究進行了經導管自擴張人工心臟瓣膜的完整設計與模擬。在支架方面，建立參數化設定，並針對支架的應變和徑向支撐力進行模擬，以確保支架的基本性能具備製造與臨床的標準；在瓣膜方面，設計了六款全新瓣膜設計，探索瓣膜幾何的各式可能性，並和二次曲面為基底的四款設計一起進行模擬比較。同時也將其中一款全新的瓣膜建置成參數化模型，並以三項參數的組合變化對瓣膜特性進行更詳細的探討。所有的瓣膜設計都以同樣的流程進行模擬，包括使用兩種不同材料：ePTFE 與 ePTFE+PET 薄膜，進行瓣口開啟與閉合的模擬。最後在實驗階段，針對其中一款瓣膜設計製造出兩種材料的瓣膜雛型品，並建置基本的流場驅動其開合運動，作為和模擬結果的對照。
並列摘要
Heart valve diseases are the dysfunction of heart valves caused by deterioration, infection, calcification, or congenital malformations. Patients with heart valve diseases suffer from decreased exercise capacity, syncope, and dyspnea. It may also cause other heart disease complications. Heart valve diseases are highly related to age. With world population aging, the prevalence of heart valve diseases also increases. The main treatment of heart valve diseases is replacing native dysfunction valves with prosthetic valves, and the one of the main choices is transcatheter aortic valve replacement (TAVR). Compared with the traditional surgical valve replacement, the intervention treatment inplants the prosthetic valve through a catheter, which enables fast and simple surgical process, minimal wound and fast recovery. The TAVR treatment was approved for usage in 2014, less than a decade ago. The commercial models are still very limited compared to the booming demand. Thus, this research aims to provide a more diverse design to transcatheter valves. With the design, simulation and experiment of the transcatheter prosthetic valve, the relation between design concept and clinical performance is studied, and the understanding toward geometric features of TAVR valves is deepened. Instead of the bio-tissue membranes most commercial products choose, this research focused on less studied artificial membrane materials, in hope of increasing the durability of TAVR. This research covers the complete design and simulation of TAVR, including the stent and valve parts. For the stent, a parametric design model is built, and the simulation effort focuses on the strain and radial force of the stent. For the valve part, six original designs were proposed and studied along with 4 second-order-surface valves. One of the new designs is turned into a parametric model, and the properties of valves are studied based on three main design parameters. All the valve simulations are done based on the same process, with two different materials: ePTFE and ePTFE+PET. Lastly, an experiment is constructed with a selected valve prototype. The flow field experiment result is then compared with the simulation results.