A parametric investigation of transcatheter aortic valve replacement performance
Midha, Prem Anand
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While transcatheter aortic valve replacement (TAVR) has many advantages over surgical replacement, it is a young technology with little evidence of long-term effectiveness. As such, there is an ever-growing need to understand factors which can lead to poor patient outcomes. Two such scenarios where there are gaps in knowledge are valve-in-valve (VIV) procedures (a failing surgical bioprosthesis replaced by a transcatheter heart valve (THV)) and THV leaflet thrombosis. While VIV may restore function to a failing bioprosthesis, adverse events such as elevated pressure pressure gradients, device malpositioning, coronary obstruction, and valve thrombosis are not uncommon. Changes in local hemodynamics around the valve have been implicated in THV thrombosis, however there is currently no understanding of how anatomical, hemodynamic, and deployment factors affect thrombosis presence and severity in TAVR. The work presented in this dissertation aims to clarify which surgical and transcatheter prosthesis type, size, and deployment position will yield the most favorable performance while minimizing adverse events. In addition, this study provides possible mechanistic explanations for the presence of TAVR leaflet thrombosis. These phenomena are investigated through novel analyses of clinical data and innovative in vitro experimental techniques. Understanding the complex interplay between anatomical, deployment, and hemodynamic conditions in such complex scenarios will help inform clinical practice and guide the development of improved next-generation valve replacements.