Polymeric Stent with Non-Linear Struts for Vessel Compliance

Solution Overview

Problem

Metallic stents cause stiffness mismatch with blood vessels, leading to issues like restenosis and localized damage due to inadequate flexibility and strength, limiting the effectiveness of current stent designs, especially in cardiovascular applications.

Innovation Solution

A tubular stent design featuring at least three primary elongate columns and non-linear struts that expand radially and longitudinally, minimizing recoil and foreshortening, and supporting increased loads with significant deformation capabilities, allowing for a balance between flexibility and strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metallic stents are used to restore structural functions of blood vessels, then strength and structural support are improved, but stiffness mismatch with the blood vessel causes localized damage and restenosis

Engineering Contradiction:

Improvestructural supportVSAvoidlocalized damage and restenosis

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by transitioning from metallic materials to polymeric materials, fundamentally altering the mechanical properties of the stent. This material parameter change enables the stent to match the compliance of blood vessels while maintaining sufficient structural support, thereby reducing stiffness mismatch and preventing localized damage and restenosis

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by using polymeric materials that combine flexibility and strength properties. These composite polymer structures provide both the necessary mechanical support to maintain vessel patency and the compliance to match natural blood vessel behavior, resolving the contradiction between strength and stiffness mismatch

Inventive Principle:

Principle #40Composite materials

2Strength

If stent geometric design is made significantly complex to improve structural performance, then strength and deformation capability are improved, but manufacturing complexity increases and limits available manufacturing methods

Engineering Contradiction:

Improvedeformation capabilityVSAvoidgeometric complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the stent structure into repeating modular units with specific geometric patterns. This segmentation allows complex three-dimensional structures to be created through repeated simple manufacturing operations, reducing overall manufacturing complexity while maintaining structural performance and deformation capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes curved and non-linear geometric designs in the stent structure to achieve complex three-dimensional configurations. These curved geometries provide enhanced structural performance and deformation capability while being manufacturable through specialized processes that can handle complex shapes efficiently

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If polymer-based stents are used to reduce stiffness mismatch, then flexibility and biocompatibility are improved, but structural strength and load-bearing capacity are reduced

Engineering Contradiction:

Improvestiffness mismatchVSAvoidload-bearing capacity

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent employs composite materials by using polymeric materials that combine flexibility and strength properties. These composite polymer structures provide both the necessary mechanical support to maintain vessel patency and the compliance to match natural blood vessel behavior, resolving the contradiction between strength and stiffness mismatch

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes curved and non-linear geometric designs in the stent structure to achieve complex three-dimensional configurations. These curved geometries provide enhanced structural performance and deformation capability while being manufacturable through specialized processes that can handle complex shapes efficiently

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 stent design reduces radial recoil, longitudinal retraction, and foreshortening, enhancing its ability to maintain structural integrity during deployment and expansion, thereby minimizing adverse effects such as restenosis and thrombosis, and providing effective scaffolding for blood vessels.

Implementation Method 1

A stent should also experience slight elastic radial recoil (usually about 10%) following removal of the balloon pressure

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20220346988A1stent

Publication Date: 2022.11.03 UNIVERSITY OF GREENWICH

AI summary

The disclosure provides a tubular stent comprising at least three primary elongate columns disposed around a circumference of the stent. The primary elongate columns substantially parallel to a longitudinal axis of the stent. The stent further comprises at least two non-linear struts disposed between each pair of circumferentially adjacent primary columns, wherein each strut extends between the circumferentially adjacent primary columns. The stent is configured to adopt a first, unexpanded configuration and a second, expanded configuration in which the stent has a greater diameter than in the first, unexpanded configuration.