Shape Memory Woven Fabric for Low-Porosity Stent Grafts

Solution Overview

Problem

Existing stent grafts for aneurysm prevention face challenges such as bulkiness, potential separation during manufacture or delivery, and increased porosity leading to undesirable leakage of body fluids due to traditional attachment mechanisms, limiting their size and effectiveness in smaller blood vessels.

Innovation Solution

A woven fabric comprising shape memory element strands and textile strands aligned in specific directions with a high proportion of floats, minimizing interlacement and porosity, and using superelastic nitinol wires for enhanced durability and biocompatibility, allowing for a tubular double weave configuration that reduces bulk and leakage risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stent grafts are constructed with separate graft and stent components attached together, then the stent graft can provide structural support and seal aneurysms, but the device becomes bulky and may separate during manufacturing or delivery

Engineering Contradiction:

Improveattachment stabilityVSAvoiddevice bulk

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the graft and stent into a single integrated woven fabric structure where shape memory element strands are woven directly into the textile fabric. This eliminates separate attachment mechanisms, reducing device bulk while maintaining structural support and sealing functions through the integrated construction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials by combining shape memory element strands (providing structural support and shape memory functionality) with textile strands (providing fabric integrity and sealing) into a single woven fabric. This composite structure eliminates the need for separate graft and stent components while maintaining both functions.

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional stent grafts use attachment mechanisms to connect graft to stent, then structural support is provided, but potential separation and leakage sites are created

Engineering Contradiction:

Improvestructural supportVSAvoidleakage resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent merges the graft and stent into a single integrated woven fabric structure where shape memory element strands are woven directly into the textile fabric. This eliminates separate attachment mechanisms, reducing device bulk while maintaining structural support and sealing functions through the integrated construction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials by combining shape memory element strands (providing structural support and shape memory functionality) with textile strands (providing fabric integrity and sealing) into a single woven fabric. This composite structure eliminates the need for separate graft and stent components while maintaining both functions.

Inventive Principle:

Principle #40Composite materials

3Reliability

If conventional stent grafts are made larger to prevent separation, then attachment stability improves, but the device cannot fit within catheters for smaller blood vessels

Engineering Contradiction:

Improveattachment stabilityVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the graft and stent into a single integrated woven fabric structure where shape memory element strands are woven directly into the textile fabric. This eliminates separate attachment mechanisms, reducing device bulk while maintaining structural support and sealing functions through the integrated construction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs shape memory elements that can change their physical parameters (shape, size) in response to temperature or stress changes. This allows the device to be delivered in a compressed state within small catheters and then expand to provide adequate structural support and sealing at the implantation site.

Inventive Principle:

Principle #35Parameter changes

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 woven fabric provides a durable, low-porosity solution that maintains shape memory characteristics, reducing the risk of separation and leakage while accommodating smaller blood vessel diameters, thus enhancing the safety and efficacy of stent grafts for aneurysm prevention.

Implementation Method 1

shape memory element strands and textile strands aligned in a first direction and textile strands aligned in a second direction. At least one of the shape memory element strands has at least one float of at least five textile strands aligned in the second direction

Methodology Applied

Scientific EffectShape memory: Shape Memory Alloy

Implementation Method 2

the textile strands comprise polyester and the shape memory element strands comprise superelastic nitinol wire

Methodology Applied

Scientific EffectSuperelasticity: Pseudoelasticity

Data Source

PatentUS20120204387A1Woven fabric with shape memory element strands

Publication Date: 2012.08.16 COOK MEDICAL TECHNOLOGIES LLC

AI summary

The disclosure relates to a woven fabric for use in an implantable medical device. The woven fabric comprises shape memory element strands woven with textile strands. At least one of the shape memory element strands has at least one float of at least five textile strands between binding points.