Thin-Walled Scaffolds with Rivet-Shaped Radiopaque Markers
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Solution Overview
Problem
Bioresorbable polymer scaffolds face challenges in maintaining radiopaque markers securely during crimping and balloon expansion due to significant plastic deformation, leading to potential dislodgment and reduced reliability, especially in thin-walled scaffolds with reduced wall thickness.
Innovation Solution
The design of thin-walled scaffolds with modified ring and link structures, including longer marker links and non-linear link struts, reduces strain energy buildup and prevents end ring flaring, while using rivet-shaped markers securely attaches radiopaque material to the scaffold, enhancing marker retention and conformability to catheters navigating tortuous anatomy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the scaffold wall thickness is reduced to improve deliverability and conformability, then the scaffold can navigate tortuous anatomy better, but the radiopaque markers become less securely attached and more prone to dislodgment during crimping and expansion
Solution Approach 1:
The scaffold structure is segmented into distinct components: thin-walled scaffold body, separate marker links, and integrated attachment features. This segmentation allows the thin-walled scaffold to maintain flexibility for navigation while the dedicated marker links provide robust marker attachment independent of the thin scaffold walls.
Solution Approach 2:
The radiopaque markers are nested within or attached to the marker links that are themselves integrated into the scaffold structure. This nested arrangement ensures markers remain securely positioned during crimping and expansion even when the scaffold walls are thin, as the markers are protected by the nested marker link structure.
2Ease of operation
If traditional crimping methods are used on thin-walled scaffolds, then the scaffold can be compressed for delivery, but significant strain energy builds up causing marker dislodgment and end ring flaring
Solution Approach 1:
The marker links are pre-configured with integrated attachment features (such as holes, slots, or clamps) designed to secure markers before crimping occurs. This preliminary configuration ensures markers are firmly attached prior to the crimping process, preventing dislodgment during the subsequent compression and expansion operations.
3Ease of operation
If the scaffold undergoes significant plastic deformation during balloon expansion, then the scaffold can be deployed from crimped state, but the radiopaque markers may dislodge due to the deformation forces
Solution Approach 1:
The marker attachment system uses composite construction combining the scaffold material with dedicated marker link structures and attachment features. This composite approach creates a robust marker attachment system that can withstand the plastic deformation forces during balloon expansion, as the marker links are specifically designed to maintain marker security during deployment.
Data Source
AI summary
A thin-walled scaffold includes a radiopaque marker connected to a link. In a first example, the marker is retained on the strut by a head at one or both ends by swaging. In a second example of a thin-walled scaffold the link is modified to avoid interference during crimping. In a third example a distal end of the thin-walled scaffold is modified to improve deliverability of the thin-walled scaffold. These features are combined in a fourth example.