Layered Stent-Graft Permeability for Sealing and Tissue Fixation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional stent-grafts are hydrophobic, preventing tissue integration and leading to susceptibility to endoleaks and migration due to their inability to facilitate biological fixation in vessels.

Innovation Solution

A variable permeability layered prosthesis with a permeable inner layer and an impermeable outer layer, along with crosslink yarns, is deployed to create a dead space where fluid coagulation allows for tissue growth and biological fixation, preventing endoleaks and migration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stent-graft material is used, then the structure provides mechanical support and sealing, but tissue integration is prevented due to extreme hydrophobicity

Engineering Contradiction:

Improvesealing capabilityVSAvoidtissue integration

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The graft material is divided into multiple layers with different permeability characteristics. The outer layer is impermeable to provide sealing and exclude the aneurysm, while the inner layer is permeable to allow tissue ingrowth and biological fixation. This segmentation resolves the contradiction by assigning different functions to different layers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the graft material are given different permeability properties. The outer surface maintains low permeability for sealing, while the inner surface has high permeability to facilitate tissue integration. This local differentiation allows simultaneous achievement of sealing and tissue integration.

Inventive Principle:

Principle #3Local quality

2Reliability

If impermeable graft material is used, then endoleak prevention is improved, but biological fixation is prevented leading to migration susceptibility

Engineering Contradiction:

Improveendoleak preventionVSAvoidbiological fixation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The graft is segmented into an impermeable outer layer for endoleak prevention and a permeable inner layer for biological fixation. The impermeable layer excludes pressurized fluid flow from the aneurysm while the permeable layer allows tissue to grow through and anchor the device, resolving the contradiction between endoleak prevention and biological fixation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The graft combines materials with contrasting permeability properties in a composite structure. The outer impermeable layer provides endoleak prevention while the inner permeable layer enables tissue ingrowth and biological fixation, creating a composite material system that achieves both functions simultaneously.

Inventive Principle:

Principle #40Composite materials

3Reliability

If hydrophobic material is used, then initial sealing is achieved, but tissue recruitment and proliferation are inhibited

Engineering Contradiction:

Improveinitial sealingVSAvoidtissue proliferation

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The graft structure is segmented into an outer hydrophobic impermeable layer for initial sealing and an inner hydrophilic permeable layer for tissue proliferation. This segmentation allows the device to achieve both initial sealing through the hydrophobic outer layer and subsequent tissue growth through the hydrophilic inner layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the graft have different hydrophobicity properties. The outer layer maintains hydrophobicity for initial sealing while the inner layer has hydrophilic characteristics that promote cell attachment, recruitment, and proliferation, resolving the contradiction between initial sealing and tissue productivity.

Inventive Principle:

Principle #3Local quality

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 solution enables biological fixation of the prosthesis in vessels, preventing endoleaks and migration, and enhances the longevity of the stent-graft by allowing tissue integration and sealing of dissections, providing a durable and long-lasting solution.

Implementation Method 1

The permeable inner layer allows fluid to enter into a dead space between the impermeable outer layer and the permeable inner layer

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

The fluid in the dead space coagulates in the dead space providing a media for tissue growth into the prosthesis

Methodology Applied

Scientific EffectCoagulation: Coagulation

Data Source

PatentUS10925714B2Variable permeability layered structure and method

Publication Date: 2021.02.23 MEDTRONIC VASCULAR INC

AI summary

The techniques of this disclosure generally relate to a variable permeability layered prosthesis including an impermeable outer layer and a permeable inner layer. The impermeable outer layer is well suited to seal a dissection opening of a dissection. The permeable inner layer allows fluid to enter into a dead space between the impermeable outer layer and the permeable inner layer. The fluid in the dead space coagulates in the dead space providing a media for tissue growth into the prosthesis. The ability of tissue to integrate into the prosthesis provides biological fixation of the prosthesis in vessels and prevents endoleaks and migration of the prosthesis.