Coated Stent Embedding via Solvent Softening
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Solution Overview
Problem
Coated stents often form gaps between the stent and the coating, increasing the stent's profile and deployment force, making them unsuitable for smaller vessels and requiring additional layers that complicate deployment.
Innovation Solution
A method involving a coating with a first and second outer diameter, where the stent's inner diameter in its expanded state is greater than the coating's first outer diameter, allowing the coating to be expanded to match or exceed the stent's inner diameter, embedding the stent into the coating, and using solvents like dimethylacetamide to soften the coating for secure attachment, potentially eliminating the need for additional coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If first and second coatings are used to reduce gap formation, then gap formation between stent and coating is reduced, but the stent profile is increased and deployment force is increased
Solution Approach 1:
The patent removes the second external coating layer from the conventional sandwich structure, retaining only the first internal coating layer. This extraction eliminates the additional profile increase while maintaining gap reduction through the single internal coating that conforms to the stent surface.
Solution Approach 2:
Instead of placing coating layers on both sides of the stent (internal and external), the invention inverts the approach by using only an internal coating that fully conforms to the stent's inner surface, eliminating the need for an external coating layer.
2Reliability
If first and second coatings are used to reduce gap formation, then gap formation between stent and coating is reduced, but deployment force is increased
Solution Approach 1:
The patent removes the second external coating layer that would contribute to deployment force requirements. By retaining only the first internal coating layer, the total force needed to deploy the stent through the coating is reduced while gap formation is still minimized through the conformal internal coating design.
3Strength
If coating diameter is increased to embed stent, then stent becomes securely attached to coating, but additional force is required for expansion
Solution Approach 1:
The patent changes the diameter parameter of the coating from the first outer diameter to the second outer diameter that is equal to or greater than the stent's inner diameter. This parameter change enables the stent to be embedded into the coating, creating secure attachment while the coating's flexibility accommodates the expansion process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces or eliminates gaps between the stent and coating, decreases the stent's profile, and lowers the deployment force required, allowing for more effective use in smaller vessels without the need for additional coatings.
Implementation Method 1
exposing at least a portion of the coating to a solvent, prior to the step of increasing the diameter of the coating, to at least temporarily soften the coating
Data Source
AI summary
A coated stent (20) for use in a medical procedure and methods of manufacturing the coated stent (20) are described. A stent component (30) has an expanded state in which an inner diameter (ds) of the stent (30) is less than or equal to an outer diameter (dc2) of a coating (40), thereby causing an inner surface (35) of the stent (30) to engage the outer surface (42) of the coating (40). In one exemplary method of manufacture, the stent (30) is disposed over the coating (40) when the coating (40) is provided with a first, smaller outer diameter (dc1). The coating (40) then is radially expanded to a second, larger outer diameter (dC2), which is greater than or equal to the inner diameter (ds) of the stent (30), to cause the outer surface (42) of the coating (40) to engage the inner surface (35) of the stent (30).