Stent Barbs Protected During Delivery via Nested Positioning
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Solution Overview
Problem
Existing stents with barbs face challenges in being protected during delivery, making it difficult or impossible to recapture or reposition them once deployed, which limits their deployment precision and safety.
Innovation Solution
A stent design featuring a coiled member deployment system where barbs are strategically positioned to be hidden during delivery, using a 'fan-blade' arrangement that circumferentially compresses the stent, allowing for controlled exposure and engagement with tissue, reducing the risk of premature engagement and enhancing repositioning capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barbs are positioned to engage tissue immediately upon deployment, then the stent achieves secure fixation, but the stent cannot be recaptured or repositioned if deployment precision is insufficient
Solution Approach 1:
The barb design allows dynamic transition between two states: a protected/retracted state during delivery where the barb is positioned within the stent structure and cannot engage tissue, and an exposed/engaged state during deployment where the barb extends to engage the vessel wall. This dynamic positioning resolves the contradiction by allowing the barb to be non-functional during delivery (enabling repositioning) and functional during deployment (ensuring fixation).
Solution Approach 2:
The barb is pre-positioned within the stent structure in a protected state before deployment, preparing it for future engagement while preventing premature engagement. This preliminary positioning allows the stent to be delivered and repositioned freely, and only upon intentional deployment does the barb extend to engage tissue, resolving the contradiction between immediate fixation and repositioning capability.
2Reliability
If barbs are exposed during delivery, then the stent can engage tissue immediately upon deployment, but the risk of premature engagement with the vessel wall increases
Solution Approach 1:
The stent structure itself serves as an intermediary protective element during delivery. The barb is positioned within the stent framework, which acts as a mediator between the barb and the vessel wall, preventing direct contact and premature engagement. Only upon intentional deployment does the barb extend beyond this protective intermediary structure to engage tissue, eliminating the harmful effect of premature engagement while maintaining reliable engagement capability.
3Length of moving object
If the stent is compressed for delivery, then the stent can be delivered through narrow vessels, but the barbs may be damaged or mispositioned
Solution Approach 1:
The barb is nested within the stent structure during delivery, with the barb positioned inside the stent framework rather than extending outward. This nesting arrangement allows the stent to be compressed to a small delivery diameter while protecting the barb from damage and maintaining its precise positioning relative to the stent struts. The barb remains protected within the nested stent structure throughout delivery and only extends upon intentional deployment.
Data Source
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AI summary
The present embodiments provide a stent (60) comprising a plurality of interconnected strut segments that enable expansion of the stent from a delivery state to a deployed state. A first strut segment and a second strut segment, of the plurality of strut segments, each comprise frontal surfaces facing radially inward in the deployed state and rear surfaces facing radially outward in the deployed state. The frontal surface of the first strut segment is at least partially stacked behind the rear surface of the second strut segment in the delivery state. A first barb (77) is coupled to at least a portion of the first strut segment. A sharpened tip of the first barb is aligned at least partially circumferentially behind at least one strut segment in the delivery state such that the sharpened tip is not radially exposed.