Title

Flow dynamics in the sinus and downstream of third and fourth generation balloon expandable transcatheter aortic valves

Document Type

Article

Publication Date

3-2022

Department

Department of Biomedical Engineering

Abstract

Objective: The early success of transcatheter aortic valve (TAV) replacement (TAVR) has fueled further innovations in the field leading to the emergence multiple iterations of TAV designs. Whether these newer designs are associated with similar hemodynamic outcomes remains unknown. Recently, the SAPIEN 3 Ultra valve received FDA approval for use in patients with published clinical outcomes. The aim of this study is (1) to evaluate and compare the flow dynamics downstream of the SAPIEN 3 Ultra and a SAPIEN 3 (2) and to evaluate and compare the resulting sinus hemodynamics and washout characteristics for a complete hemodynamic characterization. Methods: The hemodynamic assessment was performed in a pulse duplicating system and particle image velocimetry was used to assess the flow dynamics. Pressure gradient (ΔP), effective orifice area (EOA), leakage fraction (LF), velocity in the flow downstream and the sinus, viscous shear stress (VSS) downstream and adjacent to the leaflet in the sinus, and sinus washout were calculated. Results: EOA for the SAPIEN 3 Ultra was 1.81 ± 0.05 cm2 and 1.86 ± 0.05 cm2 with the SAPIEN 3, ΔP with the SAPIEN 3 Ultra was 10.56 ± 0.62 mmHg and 14.73 ± 0.79 mmHg with the SAPIEN 3, and LF with the SAPIEN 3 Ultra was 10.4 ± 0.5% and 9.7 ± 0.4% with the SAPIEN 3 (p < 0.05). The instantaneous VSS for both valves ≤ 15 Pa, which is not sufficient to induce hemolysis, but may lead to platelet activation. RSS — an indicator of blood damage — exceeded 100 Pa at peak systole with both TAVs. The sinus velocity at peak systole was 0.24 ± 0.08 m/s with the SAPIEN 3 Ultra and 0.22 ± 0.10 m/s with the SAPIEN 3. VSS range reached 3.9 Pa with the SAPIEN 3 Ultra and 4.0 Pa with the SAPIEN 3. Complete sinus washout was achieved in ∼1.5 and ∼2.4 cardiac cycles for the SAPIEN 3 Ultra and SAPIEN 3, respectively. Conclusion: Compared to its predecessor, the hemodynamic performance and sinus hemodynamics of SAPIEN 3 Ultra are comparable.

Publication Title

Journal of the Mechanical Behavior of Biomedical Materials

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