Pre-stretching Biocompatible Materials for Prosthetic Valve Stability

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Solution Overview

Problem

Prosthetic heart valves experience mechanical stresses during construction, implantation, and operation, leading to material stretching, creep, and potential damage, which can affect valve function and longevity.

Innovation Solution

Pre-stretching implantable biocompatible materials, such as pericardial tissue, by applying a tensioning force between 300 grams and 4000 grams while maintaining the material at a temperature similar to the implantation environment, reduces elongation and enhances stability and durability of the valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If material is stretched to fit over frame or crimped for storage and implantation, then valve can be constructed and implanted, but material experiences repetitive stresses leading to stretching, creep, and potential damage over time

Engineering Contradiction:

Improvevalve construction and implantationVSAvoidmaterial stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The material is pre-stretched before being attached to the valve frame to anticipate and compensate for the stretching and creep that will occur during construction, implantation, and operation. This preliminary action ensures the material maintains proper tension and fit throughout the valve's lifecycle, preventing sagging and loss of contact with frame elements

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If material thickness is reduced to provide smaller crimp profiles and more consistent folding, then valve crimping performance improves, but material may become more susceptible to damage from mechanical stresses

Engineering Contradiction:

Improvevalve crimping and foldingVSAvoidmaterial resistance to damage

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The material is subjected to controlled thermal and mechanical parameters during pre-stretching (temperature between 20°C to 50°C, tension for 1-30 days) to optimize its physical properties. This parameter control allows the material to achieve the desired thinness for crimping while maintaining sufficient strength and resistance to mechanical stresses during operation

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If material is removed or compressed to reduce thickness, then crimp profile is reduced, but other material properties such as elasticity or rigidity are altered

Engineering Contradiction:

Improvematerial thicknessVSAvoidmaterial elastic and rigid properties

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The natural viscoelastic properties of the material that cause creep and stretching are converted into a benefit through pre-stretching. By applying controlled tension and heat, the material's viscoelasticity is harnessed to achieve the desired thinness and stability, transforming what was previously a harmful characteristic into a useful one for achieving both reduced thickness and maintained structural integrity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The pre-stretching process stabilizes the material, reducing the likelihood of post-implantation stretching and improving the long-term stability and durability of the prosthetic valve, ensuring proper coaptation of leaflets and minimizing regurgitation.

Implementation Method 1

The stresses experienced by material used in prosthetic valves can negatively affect the construction and performance of such prosthetic valves. For instance, materials used in the construction of prosthetic valves typically exhibit viscoelastic properties. In particular, the materials may be prone to stretch, or creep, over time.

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

Particular embodiments relate to pre-stretching implantable biocompatible materials maintained at a temperature that is at least about a temperature of an environment into which a device incorporating such material will be implanted

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12023417B2Method for pre-stretching implantable biocompatible materials, and materials, and devices produced thereby

Publication Date: 2024.07.02 EDWARDS LIFESCIENCES CORP

AI summary

A method is provided for pre-stretching implantable biocompatible materials, such as material to be incorporated into an implantable device. A sheet of implantable biocompatible material is attached to one or more tensioning members, where tension is applied along one or more axes. Tension is applied for a period of time, and at an appropriate force, to produce a desired degree of thinning or pre-stretching of the implantable biocompatible material. During the tensioning, the implantable biocompatible material is maintained at an elevated temperature, such as a temperature that is at least substantially a temperature of an environment into which the material will be implanted.