Stent Delivery Core Assembly Recapture Mechanism
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Solution Overview
Problem
Current stent delivery systems face challenges in precisely placing and repositioning stents within blood vessels due to difficulties in recapturing, collapsing, or resheathing stents after partial expansion, especially in tortuous vessel geometries, which can lead to suboptimal placement and increased risk of vessel abrasion or perforation.
Innovation Solution
A core assembly with a constraining member and protruding member forms a gripping mechanism that secures and controls the stent, allowing for recapture, collapse, and resheathing, even after partial expansion, and includes a rotatable design to navigate tortuous paths without causing torsional stress or 'whipping', enabling precise placement and repositioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional stent delivery system is used, then the stent can be delivered to the vessel, but the stent cannot be recaptured or repositioned after partial expansion
Solution Approach 1:
The stent is nested within a delivery catheter that contains a collapsible distal portion. The distal portion of the catheter can be collapsed to contain the expanded stent, allowing recapture and repositioning. This nesting mechanism enables the stent to be contained, delivered, and recaptured through sequential collapsing and expanding of the catheter's distal portion.
Solution Approach 2:
The delivery catheter's distal portion is designed to be dynamically collapsible and expandable. This dynamic structure allows the catheter to transition between expanded and collapsed states, enabling the stent to be delivered in an expanded state and then recaptured by collapsing the distal portion, providing operational flexibility for repositioning if needed.
2Reliability
If the stent is expanded against the vessel wall, then the stent provides support, but the delivery system cannot navigate tortuous vessel paths without causing vessel abrasion or perforation
Solution Approach 1:
The distal portion of the delivery catheter is designed with dynamic collapsibility, allowing it to be compressed into a small profile for navigating tortuous vessel paths. When collapsed, the distal portion can flex and conform to complex vessel geometries without causing abrasion or perforation. Once positioned, the distal portion expands to deploy the stent against the vessel wall.
Solution Approach 2:
The distal portion of the delivery catheter is constructed as a flexible, collapsible structure that can be compressed and expanded. This flexible shell design allows the catheter to navigate tortuous paths by flexing and conforming to vessel geometry, then expand to provide stable stent deployment against the vessel wall.
3Ease of operation
If the stent is held in an expanded state during delivery, then the stent is ready for deployment, but the delivery catheter cannot be withdrawn or repositioned
Solution Approach 1:
The stent is nested within the expanded distal portion of the delivery catheter. The catheter structure is designed with nested collapsible portions that can be sequentially compressed. When the distal portion is collapsed, the stent is contained within the compressed catheter, allowing the entire assembly to be withdrawn or repositioned without damaging the stent or vessel.
Solution Approach 2:
The delivery catheter employs dynamic collapsible portions that can transition between expanded and collapsed states. This dynamic structure allows the catheter to maintain an expanded state for stable stent delivery, then collapse for withdrawal or repositioning, providing operational control while managing structural complexity through controlled mechanical transitions.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A stent delivery system, a core assembly, and methods of operating the same are provided. The delivery system can comprise a catheter and the core assembly. The core assembly can comprise a constraining member, protruding member, a core member, and a stent extending along the core member. The tubular constraining member can be spaced apart from the core member and define a capture area. The protruding member can be disposed along the core member at least partially distal of the capture area. The stent can have a first portion disposed within the capture area and a second portion, distal to the first portion, extending across or over an outer surface of the protruding member so that the protruding member and the constraining member cooperate to inhibit expansion of the first portion of the stent.