Stent Loading Lumen Geometry for Controlled Collapse and Delivery
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Solution Overview
Problem
Existing prosthetic heart valve delivery systems face challenges in achieving predictable and controlled collapsing and expanding of stents, particularly when delivering through a delivery sheath, which can lead to improper positioning, strain on the stent structure, and disruption of native valve functionality.
Innovation Solution
A loading device with a successively decreasing inner diameter lumen and a transition cell region design allows for predictable and controlled collapsing of stents, minimizing stress and strain, while maintaining moisture retention for biologically compatible materials, enabling precise delivery and expansion at the target site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balloon catheter is used to deliver a stent, then the stent can be delivered to the treatment site, but the proximal end of the stent may become dislodged and embolize during delivery
Solution Approach 1:
The stent is nested within a sheath that is itself nested within the balloon catheter. The sheath acts as an inner protective layer that keeps the stent proximal end secured during delivery, preventing embolization while allowing controlled deployment at the target site.
Solution Approach 2:
The sheath serves as an intermediary component between the stent and the balloon catheter. This intermediate structure provides a secure interface that prevents direct interaction between the stent proximal end and the blood flow, eliminating the embolization risk during delivery.
2Ease of operation
If the stent is crimped onto the balloon catheter, then the stent can be delivered, but the crimping process may damage the stent structure
Solution Approach 1:
The sheath acts as an intermediary that the stent is crimped onto instead of directly onto the balloon catheter. This intermediate surface is designed to be gentler on the stent, reducing structural damage during the crimping process while still providing secure attachment for delivery.
Solution Approach 2:
The crimping force and duration parameters are optimized and controlled during the loading process. By carefully adjusting these parameters, the stent can be securely attached to the sheath while minimizing structural damage to the stent framework.
3Reliability
If a sheath is used to protect the stent, then embolization is prevented, but the device complexity increases
Solution Approach 1:
The sheath is designed to perform multiple functions: protecting the stent from embolization, providing a gentle crimping surface, facilitating smooth delivery through vasculature, and enabling controlled deployment. By consolidating these functions into a single component, the overall device complexity is minimized while maintaining high reliability.
Data Source
Figure 1
Figure 2~3C
Figure 4A~4B
AI summary
A device and method for predictably and controlling the collapsing of a collapsible and expandable stent for subsequent translation through a delivery sheath lumen to an anatomical target such as a heart valve or intravascular location for expansion and implantation. The loading device defines in inner lumen comprising a successively decreasing, from the proximal to the distal direction, inner diameter to a region of constant inner diameter wherein the stent is in a collapsed configuration. The device and method may provide for an at least partially collapsed configuration of the stent that may be further collapsed as a part of the implantation procedure and may comprise a stent that is pre-loaded for future use.