The purpose of this research was to design, develop, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents have potential to address both of these issues, and therefore may provide improved clinical outcomes. CI-CNT stent geometry is patterned using high-resolution photolithography that provide advantages in design possibilities.To develop a coronary stent, a standard design process was followed including: background, design specifications, concept generation, development, analysis, and testing. Background research was first completed and general design specifications for coronary stent performance were compiled. Multiple design concepts were generated, evaluated, and finally a design was selected. This stent design was further developed and optimized using analytical tools along with finite element analysis. This stent design used tapered struts in repeating segments to reduce stress and improve radial force. The design was modeled and analyzed as both a flat geometry as well as in a cylindrical configuration. Mechanics of materials equations and geometry specific finite element analysis were used to guide the final coronary stent design. The stent design was tested mechanically, and additional tests were performed to verify the blood compatibility of the CI-CNT material. The flat version of the stent design was manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configuration was analyzed using an FE model of an atherosclerotic artery. This arterial FE model was created and validated by analyzing balloon angioplasty of a common stainless steel stent. The biocompatibility of CI-CNTs was explored and studied. Blood compatibility testing of CI-CNT samples was performed with results comparable in performance to stainless steel. A method of stent deployment was planned, and several other stent design concepts were analyzed. This research demonstrates that a functioning coronary stent can be manufactured from CI-CNTs. The optimized design has potential to address problems currently associated with stents. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. CI-CNT stents also need to have excellent blood compatibility to justify being used in stent applications.
College and Department
Ira A. Fulton College of Engineering and Technology; Mechanical Engineering
BYU ScholarsArchive Citation
Skousen, Darrell John, "Design Exploration and Analysis of Carbon-Infiltrated Carbon Nanotube Vascular Stents" (2013). Theses and Dissertations. 4001.
coronary stent, carbon nanotubes, blood compatibility, finite element analysis, compliant mechanism, pyrolytic carbon