Stent Jacket Fiber Diameter for Endothelial Stability
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Solution Overview
Problem
Conventional stents cause restenosis and embolic hazards due to damage to vessel tissue and the formation of scar tissue, leading to vessel blockage, and require lifelong administration of platelet aggregation reducers like Clopidogrel, which have significant side effects and do not prevent life-threatening emboli in all cases, especially in populations with hereditary antithrombin deficiency or autoimmune disorders.
Innovation Solution
A stent assembly with an expansible mesh structure formed of fibers between 7 micrometers and 18 micrometers in diameter, which promotes a stable layer of endothelial cells to reduce platelet aggregation, allowing for a shortened administration of platelet aggregation reducers and eliminating the need for their use in certain conditions, thereby minimizing embolic risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent with large mesh-like apertures is used to treat stenotic vessels, then the stent can be implanted and provide structural support, but the large apertures damage surrounding vessel tissue and allow scar tissue to protrude through, leading to restenosis
Solution Approach 1:
A tubular jacket is nested over the stent structure, creating a layered configuration where the jacket covers the stent apertures. This nested arrangement allows the stent to provide structural support while the jacket prevents tissue damage and restenosis by blocking the large apertures from contacting vessel tissue.
Solution Approach 2:
A tubular jacket comprising a polymer material is used to cover the stent. The flexible polymer shell provides a barrier that prevents direct contact between the stent apertures and vessel tissue, thereby preventing tissue damage and restenosis while maintaining the stent's structural support function.
2Object-affected harmful factors
If a tubular jacket with small apertures is deployed with a stent to prevent restenosis, then restenosis is prevented, but endothelial cell groups become unstable and form clumps that float through circulation, causing embolic events
Solution Approach 1:
The aperture size of the tubular jacket is specifically controlled to be between 5-20 micrometers, and the fiber diameter is optimized to promote stable endothelial cell attachment. These parameter optimizations prevent both restenosis and the formation of unstable endothelial cell clumps that could cause emboli.
3Object-generated harmful factors
If platelet aggregation reducers like Clopidogrel are administered lifelong to prevent emboli from jacketed stents, then embolic events are reduced, but significant side effects occur including ulcers, skin rashes, myelotoxicity, and TTP
Solution Approach 1:
The stent assembly is designed to be inherently thromboresistant through its specific aperture size (5-20 micrometers) and fiber diameter (7-18 micrometers) that promote stable endothelial cell layer formation. This self-protective design reduces platelet aggregation naturally, eliminating or reducing the need for lifelong Clopidogrel administration and its associated side effects.
4Object-generated harmful factors
If Clopidogrel is administered to reduce platelet aggregation, then some embolic events are prevented, but up to 30% of recipients fail to develop sufficiently reduced platelet aggregation and remain at risk
Solution Approach 1:
The stent assembly's specific structural parameters (aperture size 5-20 micrometers, fiber diameter 7-18 micrometers) create a surface that naturally promotes stable endothelial cell attachment and reduces platelet aggregation. This inherent property provides consistent protection across all patients, eliminating the variability seen with Clopidogrel response.
Data Source
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AI summary
A stent assembly, comprising: a. a stent jacket, comprising an expansible mesh structure, having a retracted state and a deployed state, and further wherein in the deployed state, the expansible mesh structure defines apertures, and the expansible mesh structure is formed of fibers of a diameter between about 5 micrometers and about 25 micrometers, the diameter having a property of forming a substantially stable layer of endothelial cells, covering the fibers, thus reducing platelet aggregation; and b. an expansible stent, operatively associated with the stent jacket, the stent jacket being located on the exterior of the expansible stent.