Undulating Stent Design for Kink Resistance and Conformability

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Solution Overview

Problem

Existing stents face issues with flexibility, stability, and resistance to kinking during bending, while maintaining wall apposition and side branch access, as they either experience crashing and out of tubular configuration or become too rigid, compromising conformability and increasing the risk of trauma and thrombosis.

Innovation Solution

A novel stent design featuring undulating circumferential portions and longitudinally extending portions with specific strut configurations and spacings, which provides a balance between conformability and resistance to kinking, maintaining tubular configuration and allowing for side branch access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the stent is made more flexible to improve conformability, then the stent can better adapt to vessel curvature, but the stent becomes more prone to kinking and losing tubular configuration

Engineering Contradiction:

ImproveconformabilityVSAvoidtubular configuration stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The stent is divided into multiple repeating units, each comprising struts arranged in specific patterns (e.g., first and second struts in each unit). This segmentation allows localized flexibility while maintaining overall structural integrity through the repetitive modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stent incorporates curved or angled strut configurations rather than straight rigid elements. The struts are arranged at specific angles (e.g., 45 degrees) and may include curved portions that allow bending and conformability while preserving the tubular shape through the distributed curved geometry

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If the stent is made more rigid to prevent kinking, then the stent maintains tubular configuration, but the stent trauma to the vessel wall and reduces conformability

Engineering Contradiction:

Improvetubular configuration stabilityVSAvoidvessel wall trauma

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

Different portions of the stent have different structural characteristics. For example, circumferential portions may have different strut densities or configurations compared to longitudinal portions, allowing localized flexibility where needed while maintaining rigidity in other areas to prevent overall collapse

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The stent may incorporate materials with different mechanical properties in different regions or combine materials that provide both flexibility and strength, such as using alloys or composite structures that exhibit controlled flexibility while maintaining structural integrity

Inventive Principle:

Principle #40Composite materials

3Reliability

If the stent applies sufficient force to maintain patency, then the stent effectively opens the vessel, but the stent causes undue permanent stress on the vessel wall

Engineering Contradiction:

Improvepatency maintenanceVSAvoidvessel wall stress

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The stent is designed to be expandable from a compressed delivery state to an expanded deployed state. This dynamic transformation allows the stent to be delivered through narrow catheters and then expanded to provide gentle, distributed support force rather than applying high stress during insertion

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent utilizes material properties that change with conditions, such as shape memory alloys or elastic materials, that allow the stent to expand to a predetermined diameter that provides adequate support force while limiting maximum stress on the vessel wall through controlled elastic deformation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9101504B2Stent

Publication Date: 2015.08.11 EVYSIO MEDICAL DEVICES ULC

AI summary

A stent comprises a plurality of undulating circumferential portions, each circumferential portion comprising alternating peaks and valleys; and a plurality of longitudinally extending portions connecting the plurality of undulating circumferential portions. Each of the plurality of longitudinally extending portions contains a first longitudinally extending strut and a second longitudinally extending strut circumferentially offset with respect to the first longitudinally extending strut. The first longitudinally extending strut and the second longitudinally extending strut are interconnected by a connecting portion. Circumferentially adjacent first longitudinally extending struts in a pair of circumferentially adjacent longitudinally extending portions are circumferentially spaced at a first distance and circumferentially adjacent second longitudinally extending struts in the pair of circumferentially adjacent longitudinally extending portions are circumferentially spaced at a second distance. The first distance is greater than the second distance. The present stent has a very desirable balance of conformability and flexibility while obviating or mitigating crashing, out of tubular configuration and other problems (as discussed herein).