Mid-Crown Continuous Wire Stent for Thin-Profile Radial Strength
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Solution Overview
Problem
Existing stent designs face challenges in balancing characteristics such as radial strength, strut lift, and overexpansion, particularly when using thinner profile wires, which compromise the ability of struts and crowns to open effectively.
Innovation Solution
A continuous wire stent design featuring a waveform and helical wrapping with mid-crowns between outer crowns, allowing for a non-perpendicular angle and additional mid-crowns to enhance radial strength and wire material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If thinner profile wire is used, then the stent profile is reduced, but radial strength decreases and risk of strut lifting increases
Solution Approach 1:
The stent structure is divided into multiple segments including outer crowns, mid-crowns, and struts. The addition of mid-crowns between outer crowns creates additional segmentation that allows thinner wire to achieve sufficient radial strength through increased structural complexity rather than relying on wire thickness alone.
Solution Approach 2:
The patent transitions from a traditional single-crown design to a multi-crown design with mid-crowns positioned between outer crowns. This dimensional addition creates intermediate support structures that enhance radial strength without requiring thicker wire, effectively solving the contradiction between profile reduction and strength maintenance.
2Shape
If thinner profile wire is used, then the stent profile is reduced, but risk of strut lifting increases
Solution Approach 1:
By segmenting the crown structure into outer crowns and intermediate mid-crowns, the patent distributes mechanical loads more evenly across the stent structure. This segmentation prevents excessive stress concentration at strut-crown junctions, thereby reducing strut lifting risk while maintaining a thin profile.
Solution Approach 2:
The mid-crowns are strategically positioned at specific locations between outer crowns to provide localized reinforcement where strut lifting risk is highest. This local quality enhancement allows the overall stent to maintain thin profile while having reinforced critical areas.
3Strength
If strut lengths are decreased to maintain radial strength with thinner wire, then radial strength is maintained, but ability of struts and crowns to open (overexpansion) is compromised
Solution Approach 1:
The patent adds mid-crowns as an intermediate dimension between outer crowns, creating a multi-level crown structure. This dimensional addition allows struts to be shorter while still achieving sufficient radial strength, and the mid-crowns themselves provide additional expansion capability to compensate for reduced strut overexpansion.
Solution Approach 2:
The crown structure is segmented into multiple levels (outer crowns and mid-crowns) that can expand independently. This segmentation allows the stent to achieve overall overexpansion through the coordinated expansion of multiple crown levels, even with shorter struts.
Data Source
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AI summary
A continuous wire stent includes a wire bent into a waveform and spirally wrapped into a helix having a plurality of bands that form a hollow cylindrical shape. The waveform includes a plurality of waves, each wave including a first outer crown including a first intrados, a second outer crown including a second intrados facing the first intrados, a first mid-crown disposed between the first outer crown and the second outer crown, a second mid-crown disposed between the second outer crown and an outer crown of a next wave of the waveform, a first strut connecting the first outer crown to the first mid-crown, a second strut connecting the first mid-crown to the second outer crown, a third strut connecting the second outer crown to the second mid-crown, and a fourth strut connecting the second mid-crown to the outer crown in the next wave of the waveform.