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New concepts in transcatheter mitral valve replacement

University of British Columbia

The most prevalent form of moderate to severe valve disease in developed countries is mitral regurgitation (MR), which affects ~10% of people older than 75 years of age. Roughly half of patients with severe symptomatic MR are not referred for surgery due to risks of age, comorbid factors and frailty. With these outcomes, a minimally invasive procedural option is required. The emergence of transcatheter aortic valve replacement (TAVR) has segued the development of transcatheter mitral valve (MV) repair devices. Transcatheter mitral valve repair has become a well-established alternative for patients with severe primary and secondary mitral regurgitation (MR) and with a perceived surgical risk. Transcatheter mitral valve replacement (TMVR) could become a more complete form of reduction of severe MR compared to MV repair devices, albeit with significant engineering challenges and all the risks associated with a bioprosthetic heart valve. The development of TMVR devices has become prominent while companies race to become the first commercially available system. Preclinical and clinical trials have shown promising results, showcasing the feasibility of total valve replacement utilizing transcatheter procedure techniques. This thesis is focused on evaluating the feasibility of novel TMVR devices. It is comprised of three major components: design and fabrication of MV leaflets; design of TMVR stents; as well as design and fabrication of a miniaturized heart simulator. Additionally, an extensive literature review of relevant clinical and preclinical designs to fully map out the TMVR landscape. A novel bileaflet valve was designed for implantation into a TMVR stent. The kinematics of the leaflet motion were evaluated, resulting in a positive feasibility assessment of the design with room for further iterations. An additional bileaflet valve was designed to perform a computational model evaluating wrinkle-induced tearing of prosthetic MVs. A trileaflet valve was designed to evaluate the feasibility of the cryogel material for heart valves. Four stents were designed with intent for fabrication in the future to evaluate their viability. The heart simulator was designed and fabricated to aid in the evaluation of the kinematics of fabricated heart valves, with plans to further improve the design in the future.

Text

2020-04-23

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/74136

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/