Poster T13 - A Comparative Analysis of Clinical, Regulatory, and Engineering Performance Metrics for Prosthetic Heart Valves

Introduction: Prosthetic heart valve (PHV) designs have evolved considerably over the past decades with the emergence of percutaneous and transcatheter valves. Hemodynamic performance metrics have also evolved during the past decades and we can gain considerable insights comparing performance metrics across clinical practice, engineering testing standards, and recent research. In fact, heart valve performance metrics have transcended beyond transvalvular metrics and now include a more holistic evaluation of ventricular performance in the presence of PHVs.

Materials and

Methods: Evaluating the hemodynamic performance of heart valves, including PHVs, requires a systematic approach as well as adherence to existing standards. In clinical practice, systematic methods for assessing heart valve function involve cardiovascular imaging modalities, namely echocardiography and MRI, to quantify the in vivo hemodynamic performance of both native and PHVs. The American Society of Echocardiography (ASE) in fact sets standards and guidelines for clinical evaluation of performance heart valves. In January 2024, the ASE even introduced new guidelines for percutaneous valves and emphasis on the integration of multimodality imaging—including computed tomography (CT), cardiac magnetic resonance (CMR), and echocardiography—for evaluating prosthetic heart valves (PHVs). In engineering and scientific practice, the Food and Drug Administration (FDA) and the International Organization for Standardization (ISO) drive valve performance evaluation and ultimately approval. The FDA guidelines outline the partial recognition of ISO 5840-1:2021, a standard for cardiovascular implants, specifically cardiac valve prostheses. ISO standards have set forth their own set of guidelines that engineers and researchers must adhere to when conducting benchtop testing to evaluate the performance of any heart valve. A comparative analysis of clinical, engineering testing, and regulatory hemodynamic performance metrics can provide some interesting insights for future work.

Results, Conclusions, and Discussions: Our findings revealed some common transvalvular performance metrics for prosthetic heart valves across ASE, FDA, and ISO standards, respectively transvalvular velocity, effective orifice area, transvalvular pressure gradient, forward flow rate, and regurgitant volume. Our findings also revealed distinct transvalvular performance metrics. As an example, ASE metrics included Doppler Velocity Index (DVI), Gorlin Area, velocity time integral, pressure recovery, E-wave velocity, A-wave velocity. FDA or ISO metrics included regurgitant fraction, viscous shear stress, forward flow volume, closing volume, etc. Research studies have also pointed to other performance metrics that are not currently part of the standard practice of heart valve performance, but certainly could be in the future. Such metrics include vortex ring formation number, ventricular energy loss, coefficient of performance, etc.

This investigation comparing clinical, engineering, regulatory, and research performance metrics pertinent to assessing both heart valve performance and ventricular performance in the presence of a PHV has revealed opportunities for future research and implications for clinical and regulatory practice. One such opportunity is to identify and understand performance metrics that can bridge clinical metrics and regulatory metrics. Another opportunity is the inclusion of new performance metrics to evaluate the efficacy of PHVs in the heart.

With advancements in prosthetic heart valve designs, it is also imperative to advance our metrics to evaluate the performance of these devices in the presence of the heart. A comparative analysis of the current state of clinical practice with regulatory metrics and research findings reveals some unique opportunities that can impact clinicians, engineers, scientists, and regulatory bodies. Bridging the gaps between clinical practice, FDA and ISO requirements and standards, as well as research findings offers translation that can improve all contexts of PHV performance metrics. Implications also exist for improving PHV designs as a result of advancing performance metrics.

Acknowledgements (Optional): The authors would like to acknowledge the National Science Foundation and internal Wake Forest University funds for supporting the work and personnel of this research. This material is based upon work supported by the National Science Foundation under an IPA agreement. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Lastly, the authors would like to acknowledge Mr. Brandon Eberl for supporting this research.