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<p>Transcatheter aortic valves (TAVs) typically operate on non-circular rings, but the impact of annular ellipticity on valve mechanics remains insufficiently quantified. In this study, we present a finite element (FE) framework of a 27&#xa0;mm Allegra TAV that reproduces the complete model, including stent and pericardial skirt and leaflets. The leaflets were represented using a general shell formulation that decouples the in-plane and bending responses, leading to a hybrid shell–membrane finite element model. A linear elastic constitutive law was calibrated through inverse FE analysis based on cantilever bending experiments performed on bovine pericardium. The model was validated against in vitro pulse duplicator tests for circular and highly elliptical geometries, reproducing distinctive features such as full systolic opening and the asymmetric ‘pinwheel’ pattern during diastolic closure. Once validated, the model is used to investigate the impact of annular ellipticity across six annular aortic geometries. Each geometry was evaluated in two limiting orientations of the ellipse’s major axis (0<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(^\circ\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation> and 90<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(^\circ\)</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>) to analyse the model response in terms of valve coaptation. These results identify annular geometry and alignment as major factors in valve leaflet coaptation asymmetry and this asymmetry was found to correlate with increased stress concentration, which could compromise long-term valve function.</p>

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A hybrid phenomenological finite element model of transcatheter aortic valve leaflet behaviour under non-circular annular deployment: in vitro validation and biomechanical insights

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年7月21日

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  • David Agudo,
  • Pablo Comesaña,
  • Sofía Suárez,
  • Irea Lopez-Garcia,
  • Abraham Segade,
  • Enrique Casarejos,
  • Cesar Veiga,
  • Laura Busto,
  • Victor Alfonso Jimenez-Díaz,
  • Maximilian Kütting,
  • Andres Iñiguez

摘要

Transcatheter aortic valves (TAVs) typically operate on non-circular rings, but the impact of annular ellipticity on valve mechanics remains insufficiently quantified. In this study, we present a finite element (FE) framework of a 27 mm Allegra TAV that reproduces the complete model, including stent and pericardial skirt and leaflets. The leaflets were represented using a general shell formulation that decouples the in-plane and bending responses, leading to a hybrid shell–membrane finite element model. A linear elastic constitutive law was calibrated through inverse FE analysis based on cantilever bending experiments performed on bovine pericardium. The model was validated against in vitro pulse duplicator tests for circular and highly elliptical geometries, reproducing distinctive features such as full systolic opening and the asymmetric ‘pinwheel’ pattern during diastolic closure. Once validated, the model is used to investigate the impact of annular ellipticity across six annular aortic geometries. Each geometry was evaluated in two limiting orientations of the ellipse’s major axis (0 \(^\circ\) ∘ and 90 \(^\circ\) ∘ ) to analyse the model response in terms of valve coaptation. These results identify annular geometry and alignment as major factors in valve leaflet coaptation asymmetry and this asymmetry was found to correlate with increased stress concentration, which could compromise long-term valve function.