Virtual heart valve
First Claim
1. A method of modeling a prosthetic heart valve with a computer program, comprising:
- entering two-dimensional geometry and material parameters of a flexible heart valve leaflet into a finite element analysis program to define a simulated leaflet;
entering the three-dimensional geometry and material parameters of a heart valve support frame using the finite element analysis program to define a simulated support frame; and
deriving the topography of a plurality of the simulated leaflets in three dimensions by imposing edge constraints on the simulated leaflets at their intersections with the support frame, whereinthe simulated support frame is tubular or frusto-conical, wherein the plurality of simulated leaflets are arranged in a tube or frusto-cone within the support frame, and wherein the edge constraints comprise a continuous line fixing the tube or frusto-cone of simulated leaflets around an inflow end of the simulated support frame, and a plurality of generally axial lines located at the intersections of adjacent axial edges of the simulated leaflets.
1 Assignment
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Accused Products
Abstract
A computational technique to construct a 3-D valve leaflet geometry. The invention pertains to methodology to construct a 3-D heart valve leaflet geometry using finite element analysis (FEA) to simulate the manual assembly process or, in other words, provide a virtual assembly process as an input to a subsequent simulated valve testing step. The simulated valves may be subjected to simulated cyclic valve opening and closings and the stress levels induced therein monitored. Simulated valve designs with lower principal stresses can then be selected for prototyping. Proposed valves can be subjected to cyclic fatigue stress testing under simulated physiologic conditions to study valve durability.
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Citations
20 Claims
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1. A method of modeling a prosthetic heart valve with a computer program, comprising:
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entering two-dimensional geometry and material parameters of a flexible heart valve leaflet into a finite element analysis program to define a simulated leaflet; entering the three-dimensional geometry and material parameters of a heart valve support frame using the finite element analysis program to define a simulated support frame; and deriving the topography of a plurality of the simulated leaflets in three dimensions by imposing edge constraints on the simulated leaflets at their intersections with the support frame, wherein the simulated support frame is tubular or frusto-conical, wherein the plurality of simulated leaflets are arranged in a tube or frusto-cone within the support frame, and wherein the edge constraints comprise a continuous line fixing the tube or frusto-cone of simulated leaflets around an inflow end of the simulated support frame, and a plurality of generally axial lines located at the intersections of adjacent axial edges of the simulated leaflets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 15)
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11. A method of testing a simulated prosthetic heart valve, comprising:
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providing a two-dimensional drawing of a simulated heart valve leaflet having a cusp edge and a free edge; simulating a valve assembly procedure to form a simulated heart valve by attaching the cusp edge of a plurality of the leaflets to a simulated 3-dimensional heart valve support frame using finite element analysis software, and applying edge constraints at the support frame to the cusp edges; applying nonlinear tissue material constitutive properties in the finite element analysis software; applying simulated valve opening and closing fluid cycles to the simulated heart valve; and monitoring simulated stresses induced in the simulated heart valve by the application of simulated valve opening and closing cycles, wherein the simulated support frame is tubular or frusto-conical, wherein the plurality of simulated leaflets are arranged in a tube or frusto-cone within the support frame, and wherein the edge constraints comprise a continuous line fixing the tube or frusto-cone of simulated leaflets around an inflow end of the simulated support frame and a plurality of generally axial lines located at the intersections of adjacent axial edges of the simulated leaflets. - View Dependent Claims (12, 13, 14)
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16. A method of selecting a prosthetic heart valve design for prototyping, comprising:
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providing a two-dimensional drawing of a simulated heart valve leaflet having a cusp edge and a free edge; simulating a valve assembly procedure by attaching the cusp edge of a plurality of the leaflets to a simulated 3-dimensional heart valve support frame using finite element analysis software; imposing edge constraints on the leaflets at their intersections with the support frame; applying nonlinear tissue material constitutive properties in the finite element analysis software; applying simulated valve opening and closing fluid cycles; obtaining a stress distribution in the leaflets; performing the steps above for at least two simulated heart valves; and building a prototypical valve based on a comparison of the observed stress distribution in the leaflets of the simulated valves, wherein the simulated support frame is tubular or frusto-conical, wherein the plurality of simulated leaflets are arranged in a tube or frusto-cone within the support frame, and wherein the edge constraints comprise a continuous line fixing the tube or frusto-cone of simulated leaflets around an inflow end of the simulated support frame and a plurality of generally axial lines located at the intersections of adjacent axial edges of the simulated leaflets. - View Dependent Claims (17, 18, 19, 20)
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Specification