Stent Delivery Wire with Bumps for Radial Expansion
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Solution Overview
Problem
Braided stents often fail to fully open and conform to the vessel wall due to low opening forces, leading to unintentional braid movement and difficulty in repositioning after deployment.
Innovation Solution
An expandable element with a distal anchor, proximal anchor, and a braided intermediate portion is delivered via a delivery wire that applies radial force through a shapeable segment to expand the stent, allowing for improved vessel wall conformity and repositioning capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a braided stent is used for intravascular angioplasty, then the stent can be delivered in a collapsed configuration through a catheter, but the stent may not fully open to conform to the vessel wall due to low opening forces
Solution Approach 1:
The delivery system is segmented into multiple functional components: a catheter for delivery, an expandable braided stent, and a delivery wire with distinct bump structures (first bump for distal anchor, second bump for proximal anchor). This segmentation allows each component to perform its specific function independently, enabling controlled expansion and repositioning capabilities.
Solution Approach 2:
The delivery wire acts as an intermediary tool between the operator and the stent. It transmits mechanical forces through its bump structures to the stent's anchor members, enabling controlled expansion and repositioning without direct manipulation of the stent itself.
2Reliability
If a braided stent is deployed, then the stent can provide structural support, but unintentional braid movement occurs due to insufficient expansion
Solution Approach 1:
The delivery system performs preliminary actions through the delivery wire's bump structures: the first bump pushes the distal anchor to initiate expansion, and the second bump pushes the proximal anchor to complete expansion. This preliminary controlled expansion ensures the stent is fully opened before final deployment, preventing subsequent movement.
Solution Approach 2:
The stent transitions through parameter changes from a collapsed low-diameter configuration during delivery to an expanded high-diameter configuration at the treatment site. The delivery wire facilitates this parameter change by applying controlled radial forces to overcome the stent's memory and achieve full expansion for stable vessel wall conformity.
3Ease of operation
If the stent is separated from the delivery wire for deployment, then the stent can be released, but repositioning becomes impossible
Solution Approach 1:
The delivery system incorporates dynamic control through the delivery wire with movable bump structures. The first bump can push the distal anchor, the second bump can push the proximal anchor, and these actions can be performed in sequence or reversed. This dynamic control allows the operator to adjust the expansion state and reposition the stent if needed, providing flexibility during the procedure.
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 the stent to expand and conform more effectively to the vessel wall, addressing issues of incomplete expansion and facilitating repositioning by using a delivery wire with bumps and a shapeable segment to apply controlled radial forces.
Implementation Method 1
a shaped segment that can be moved to apply a radial force from within the braided intermediate portion to expand the braided intermediate portion
Data Source
AI summary
A method for implanting a stent by providing an implantation system including a catheter, an expandable element, and a delivery wire, moving a first portion of the expandable element to exit the catheter, and maintaining a second portion of the expandable element within the catheter to establish a partially implanted configuration. Then moving the delivery wire independent of the expandable element in the partially implanted configuration, and enlarging a circumference of the expandable element in response to the moving the delivery wire.