Segmented Uncaging Stent for Post-Implant Vessel Expansion
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Solution Overview
Problem
Existing stents, both metallic and biodegradable, suffer from issues such as jailing the lumen, limited ability to further expand after implantation, excessive inward recoil, and reduced compliance, leading to vessel re-occlusion and negative clinical events.
Innovation Solution
The development of non-degradable stents with circumferentially separable axial links and rings that unlock or separate over time, allowing for increased compliance and reduced radial strength post-implantation, enhancing vessel remodeling and compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic stents with high radial strength are used to support the vessel and prevent recoil, then the vessel remains open with high crush resistance, but the stent jails the lumen and prevents further expansion and positive remodeling
Solution Approach 1:
The stent is divided into multiple axially-spaced segments with circumferentially separable links. These links can separate in response to physiological conditions (such as pH changes, enzymatic activity, or mechanical stress), allowing the stent to transition from a continuous high-strength structure to a segmented structure that permits vessel remodeling and further expansion while maintaining initial structural support
2Ease of operation
If the stent is maintained in crimped configuration using a constraint upon delivery, then the profile is large and less deliverable, but the stent can be precisely positioned before expansion
Solution Approach 1:
The stent segments are pre-configured with separable links that are held together by physiological triggers present in the delivery system environment. The stent is crimped without complex external constraints, and the separable links naturally maintain the compressed state until exposed to physiological conditions (such as body temperature, pH, or specific enzymes) that trigger their separation, enabling self-expansion and reducing delivery system complexity
3Adaptability or versatility
If shape memory self expandable alloys are used to provide stent expansion, then the lumen can expand after implantation, but the radial strength is insufficient leading to excessive inward recoil and lumen narrowing
Solution Approach 1:
The stent combines shape memory alloy segments with high-strength metallic structures. The shape memory segments provide the ability to expand and adapt to physiological conditions, while the high-strength metallic components (such as cobalt-chromium or elgiloy alloys) provide the necessary radial strength and crush resistance. The separable links connect these different material types, creating a composite structure that exhibits both high initial strength and subsequent adaptability
Data Source
AI summary
A stent (scaffold) or other luminal prosthesis comprising circumferential structural elements which provide high strength after deployment and allows for scaffold to uncage, and/or allow for scaffold or luminal expansion thereafter. The circumferential scaffold is typically formed from non-degradable material and will be modified to expand and/or uncage after deployment.