Abstract 4142998: Optimizing Transcatheter Aortic Valve Design to Mitigate Subclinical Leaflet Thrombosis

Introduction: Subclinical leaflet thrombosis is an increasingly recognized complication in patients undergoing transcatheter aortic valve replacement (TAVR). Patients with hypoattenuated leaflet thickening (HALT) and reduced leaflet motion (RELM) have a higher incidence of strokes and transient ischemic attacks. Early clinical data suggested that HALT is more common in supra-annular than intra-annular transcatheter aortic valves (TAVs). It was postulated that intra-annular TAVs have a larger neo-sinus volume and are potentially at a higher risk of blood flow stagnation in the neo-sinus region than supra-annular devices. However, recent clinical data obtained from the Evolut Low-Risk trial and the PARTNER 3 Cardiac CT sub-study showed that the incidence of HALT was comparable between supra-annular Evolut R (30.9%) and intra-annular SAPIEN 3 (28%) devices at one year. Hypothesis: We hypothesized that TAV leaflet design plays a vital role in the initiation and growth of leaflet thrombosis. Aim: The study aimed to optimize the leaflet and frame geometry of TAVs to mitigate the risk of subclinical leaflet thrombosis using an interactive parametric design platform that streamlines the engineering design process. Methods: We developed an automated computational framework to optimize the design of TAV leaflets in ANSYS Workbench, aiming to minimize (i) blood stasis on the surface of the TAV leaflets and (ii) the peak stress experienced by the tissue. Seven design variables were defined to modify the leaflet geometry and valve position (Figure 1). Results: The design platform revealed a complex response of the design variables, underscoring the importance of numerical optimization to obtain an optimal valve geometry. A considerable reduction in the blood stasis and maximum in-plane principal stress (31%) was observed in comparison to commercially available TAVs. Conclusions: The simulation results revealed that the leaflet geometry plays a vital role in the degree of blood stasis on the surface of the TAV leaflets and the stress experienced by the tissue. The optimized TAV design could reduce the risk of subclinical leaflet thrombosis in patients undergoing TAVR.