Bias-Wrapped Membrane Conformability for Varying Stent Frame Geometries

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Solution Overview

Problem

Implantable medical devices with stent and graft components often face challenges in maintaining conformability without hindering stent movement, especially when dealing with frame elements of differing diameters, pitches, or angles.

Innovation Solution

The use of a bias-wrapped membrane comprising helically wrapped films with fibrils arranged in an arcuate shape, which is conformably arranged on the frame elements to adapt to varying diameters, pitches, and angles, while allowing for sliding motion to maintain flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a graft component is attached to frame components with varying diameters, pitches, or angles, then the device can cover diverse geometries, but the graft component may hinder stent movement and reduce conformability

Engineering Contradiction:

Improveability to cover frame elements with varying geometriesVSAvoidstent movement freedom

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The graft component is designed with dynamic characteristics, including helical wrapping with specific pitch angles and fibrillar structures that allow sliding and deformation. This enables the graft to adapt its shape and movement properties to match the underlying frame geometry, preventing hindrance of stent movement while maintaining coverage.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The graft component utilizes parameter changes in its helical wrapping configuration, where the wrap angle and pitch are specifically designed to correspond with the frame element geometry. By adjusting these parameters, the graft can conform to varying diameters, pitches, and angles without creating restrictive constraints on stent movement.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a rigid graft component is used to cover frame elements, then coverage stability is improved, but conformability and flexibility are reduced

Engineering Contradiction:

Improvecoverage stabilityVSAvoidconformability to frame geometry

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The graft component is constructed as a flexible thin film or shell with helical wrapping and fibrillar structures. This flexible construction allows the graft to conform to the three-dimensional geometry of the frame elements while maintaining structural integrity and coverage stability. The flexibility enables the graft to adapt to varying diameters, pitches, and angles without rigidity-induced deformation.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If the graft component is designed to conform to frame geometry, then adaptability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveconformability to varying diameters, pitches, and anglesVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The graft component is segmented into discrete helical wrapping layers with specific pitch angles and fibrillar structures. This segmentation allows each layer to be independently manufactured and then assembled, simplifying the overall manufacturing process while maintaining the ability to conform to complex frame geometries. The modular helical structure can be produced using standard manufacturing techniques.

Inventive Principle:

Principle #1Segmentation

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

This solution enables the implantable medical device to remain conformable and flexible, preventing stent movement hindrance while effectively covering frame elements with diverse geometries, thus enhancing the device's adaptability and functionality.

Implementation Method 1

a bias-wrapped membrane including at least a first helically wrapped film and a second helically wrapped film overlapping the first helically wrapped film at an angle, each arranged on the first side of the first structural element

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The first plurality of fibrils are configured to slide relative to adjacent arcuate fibrils

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS20250134681A1Conformable cover for medical devices

Publication Date: 2025.05.01 WL GORE & ASSOC INC

AI summary

An implantable medical device includes a frame including a first structural element having a first diameter and a bias-wrapped membrane including at least a first helically wrapped film and a second helically wrapped film overlapping the first helically wrapped film at an angle, arranged on a first side of the first structural element. The first helically wrapped film has a first plurality of edges having an arcuate shape extending along the first side of the first structural element and the arcuate shape of the first plurality of fibrils extends for a majority of the first structural element side.