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Transcatheter heart valve with variable geometric configuration: in vitro evaluation
Ernest Young1, Ji-Feng Chen, Owen Dong
1School of Medicine, Case Western Reserve University, Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, OH, USA.
Artificial Organs
|September 29, 2011
Summary
Transcatheter aortic valve (TAV) geometry significantly impacts performance. Nonideal shapes increase leakage and alter pressure gradients, highlighting the need for optimized TAV design to reduce paravalvular leakage.
Area of Science:
- Biomedical Engineering
- Cardiovascular Devices
- Fluid Dynamics
Background:
- Current transcatheter aortic valve (TAV) technology is prone to paravalvular leakage.
- Leakage is linked to calcification and nonideal TAV geometry.
- Understanding TAV hydrodynamics is crucial for improving device performance.
Purpose of the Study:
- To evaluate the hydrodynamic performance of different transcatheter aortic valve geometries.
- To assess the impact of intravalvular considerations on TAV function.
- To compare key hemodynamic parameters across various TAV configurations.
Main Methods:
- Three size 26 mm TAV devices were fabricated with nominal, elliptical, triangular, and undersized shapes.
- A half-constriction geometry was also tested, constraining only part of the stent.
- Hydrodynamics were assessed using a pulse duplicator, measuring transvalvular pressure gradient (TVG), effective orifice area (EOA), and regurgitant fraction.
Main Results:
- Nominal TAV shape showed a higher TVG (6.2 ± 0.3 mm Hg) than most configurations, except undersized valves.
- EOA was smaller in nominal TAVs (1.7 ± 0.1 cm²) compared to triangular and half-elliptical designs.
- Undersized geometries resulted in smaller EOAs, while nominal shapes exhibited less regurgitation (6.7 ± 1.4%) than most nonideal configurations.
Conclusions:
- Variable TAV geometries significantly alter transvalvular pressure gradient, effective orifice area, and regurgitant fraction.
- Nonideal configurations, particularly those with constrictions, tend to increase intravalvular regurgitation.
- Optimizing TAV geometry is essential for minimizing paravalvular leakage and improving hemodynamic efficiency.
