Single Nitinol Wire Stent with Dual Layer Flow Diversion
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Solution Overview
Problem
Current vascular embolization techniques for treating aneurysms face challenges in effectively occluding blood flow and maintaining stent positioning within the vessel, with existing stents either lacking sufficient anchoring force or having free ends that can damage vessels.
Innovation Solution
A stent design featuring a cylindrical body woven from a single nitinol wire with loops and marker members for visualization, along with a dual layer stent configuration that includes an outer anchoring stent and an inner flow-diverting layer, which can be independently expanded to modify blood flow and induce thrombosis within an aneurysm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stent is used to reinforce the vessel wall around the aneurysm, then the structural support is improved, but the anchoring force and positioning stability are insufficient
Solution Approach 1:
The stent is divided into multiple segments or sections along its length, with each segment capable of independent expansion and anchoring. This segmentation allows the stent to achieve both structural support and reliable positioning by anchoring at multiple locations along the vessel wall.
Solution Approach 2:
The stent transitions from a compressed low-dimensional state during delivery to an expanded three-dimensional state at the target site. This dimensional change enables the stent to achieve adequate anchoring force and positioning stability while maintaining a compact profile for delivery through catheters.
2Ease of operation
If existing stents are designed with free ends for delivery, then the ease of deployment is improved, but the risk of vessel damage during deployment and retraction increases
Solution Approach 1:
The stent design integrates multiple functions into a single device: it serves as both a delivery-compatible component with a catheter and a final implantable structure with secured ends. The stent can be delivered through the catheter and then deployed to anchor securely in the vessel, eliminating the harmful free ends while maintaining ease of deployment.
Solution Approach 2:
The stent is nested within the delivery catheter during delivery, with the catheter protecting the stent and surrounding tissue. Upon deployment, the stent expands from its nested state to its functional configuration, securing the vessel walls and eliminating exposed free ends that could cause damage.
3Quantity of substance
If a densely woven stent is placed over the aneurysm mouth, then the blood flow reduction is improved, but the thrombogenicity and occlusion effectiveness are insufficient
Solution Approach 1:
The stent employs different weaving densities at different locations: a densely woven portion at the aneurysm mouth to reduce blood flow, and a more open weave in other sections to maintain thrombogenicity. This local variation in structure allows the stent to simultaneously achieve blood flow reduction and promote thrombosis for effective occlusion.
Solution Approach 2:
The stent incorporates materials or surface treatments with different properties in different sections. The densely woven portion may have one material composition optimized for flow reduction, while other portions have different compositions or surface characteristics that enhance thrombogenicity and occlusion effectiveness.
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 enhances anchoring and blood flow modification, reducing the risk of stent damage during deployment and retraction, while effectively occluding aneurysms by promoting thrombosis, thereby improving treatment efficacy.
Implementation Method 1
a stent design featuring a cylindrical body woven from a single nitinol wire
Implementation Method 2
The stent can be compressed over the distal marker band such that the stent's proximal loops and proximal marker members are disposed between the distal and proximal marker bands on the pusher member
Implementation Method 3
some of which include marker members used for visualizing the position of the stent
Data Source
Figure 1~2
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Figure 6
AI summary
In one embodiment according to the present invention, a stent is described having a generally cylindrical body formed from a single woven nitinol wire. The distal and proximal ends of the stent include a plurality of loops, some of which include marker members used for visualizing the position of the stent. In another embodiment, the previously described stent includes an inner flow diverting layer.