Conformable Stent-Graft Delivery System for Curved Vessels

Solution Overview

Problem

Endovascular grafts often fail to conform accurately to curved vessels, leading to issues like 'birds beaking' where blood flows underneath the graft, causing device migration, stent fatigue, and endoleaks due to non-ideal deployment in curved anatomy.

Innovation Solution

A delivery system with a cannula and stent-graft design featuring a locking member and diameter reducing members that allow the stent-graft to be conformed to curved vessels by forming a reduced diameter configuration with lobes, ensuring better apposition against the vessel wall.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a substantially cylindrical stent-graft is deployed in a curved vessel, then the stent-graft maintains its structural integrity and cylindrical shape, but it fails to conform to the inner curvature of the vasculature, creating gaps and leading to device migration and endoleaks

Engineering Contradiction:

Improvecylindrical shapeVSAvoidconformity to vessel curvature

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The stent-graft is divided into multiple modular segments or units that can be independently positioned and oriented. This segmentation allows the prosthesis to adapt to curved vessel geometries by arranging the cylindrical segments to follow the vessel's curvature, thereby maintaining structural integrity while achieving conformability to prevent gaps and device migration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single rigid cylindrical structure to a multi-dimensional modular configuration. The stent-graft system incorporates radial and longitudinal modularity, enabling the prosthesis to three-dimensionally conform to curved vessels while preserving the cylindrical integrity of individual graft segments through precise spatial arrangement

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If the stent-graft is made more flexible to conform to curved vessels, then conformity to vessel curvature improves, but the structural strength and resistance to stent fatigue may be compromised

Engineering Contradiction:

Improveconformity to vessel curvatureVSAvoidresistance to stent fatigue

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The stent-graft is divided into multiple modular segments or units that can be independently positioned and oriented. This segmentation allows the prosthesis to adapt to curved vessel geometries by arranging the cylindrical segments to follow the vessel's curvature, thereby maintaining structural integrity while achieving conformability to prevent gaps and device migration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stent-graft incorporates composite material construction combining flexible polymers for the graft fabric with high-strength metal or alloy stent framework. This composite structure provides both the flexibility needed to conform to curved vessels and the structural strength to resist fatigue, balancing conformability with mechanical durability

Inventive Principle:

Principle #40Composite materials

3Reliability

If the stent-graft is deployed to fully expand and seal against the vessel wall, then sealing effectiveness improves, but the risk of birds beaking and blood flow underneath the graft increases in curved anatomy

Engineering Contradiction:

Improvesealing effectivenessVSAvoidblood flow underneath graft

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stent-graft is divided into multiple modular segments or units that can be independently positioned and oriented. This segmentation allows the prosthesis to adapt to curved vessel geometries by arranging the cylindrical segments to follow the vessel's curvature, thereby maintaining structural integrity while achieving conformability to prevent gaps and device migration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stent-graft incorporates varying structural properties at different locations to optimize performance. The proximal end features enhanced conformability structures such as tapered or flared designs that specifically address the birds beaking problem in curved vessels, while the body maintains full expansion for sealing. This local differentiation ensures both sealing effectiveness and prevention of blood flow underneath the graft in curved anatomy

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP2471498B1Conformable prosthesis delivery system

Publication Date: 2018.01.17 COOK MEDICAL TECHNOLOGIES LLC

Figure 1~1a
Figure 1b
Figure 2~2a

AI summary

A delivery system may include a stent-graft (112), a locking member (150), and one or more diameter reducing members (160). The stent-graft may include a tubular graft comprising first and second longitudinally extending sides disposed opposite each other and connected at a tangent line. When the locking member is in a locked position, the locking member restrains a surface of the graft against the cannula. The first diameter reducing member may be slidably connected to a first portion of the graft that is disposed proximate the tangent line and may be slidably connected to a second portion of the graft that is spaced circumferentially away from the tangent line. When the first diameter reducing member is in a restrained position, the second portion of the graft is drawn toward the first portion of the graft and the proximal portion of the stent-graft has a reduced diameter configuration with at least two lobes.