Thin-Walled Scaffolds with Flexible Distal Ends
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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 development of thin-walled scaffolds with modified ring and link structures, including sinusoidal and zig-zag patterns, and the use of rivet-shaped radiopaque markers to secure the markers within the scaffold, reducing strain energy buildup and preventing marker dislodgment during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the scaffold wall thickness is reduced to lower profile, then deliverability through tortuous anatomy is improved, but marker securement reliability deteriorates due to significant plastic deformation during crimping and expansion
Solution Approach 1:
The patent applies local quality by creating a distal end portion with different structural characteristics than the rest of the scaffold. The distal end has a flexible configuration with reduced structural rigidity, allowing it to deform independently during crimping and expansion while the proximal portion maintains sufficient rigidity for marker securement. This localized flexibility resolves the contradiction by protecting the marker securement region from excessive deformation while enabling the distal end to accommodate tortuous anatomy.
Solution Approach 2:
The scaffold is segmented into distinct functional regions: a proximal portion with standard structural integrity for marker securement, and a distal end portion with modified flexible structure. This segmentation allows different parts of the scaffold to perform different functions - the proximal portion maintains reliability for marker attachment while the distal portion provides flexibility for navigation, resolving the contradiction between overall flexibility and local securement reliability.
2Ease of operation
If the scaffold undergoes significant plastic deformation during balloon expansion, then deployment is achieved, but marker dislodgment occurs reducing reliability
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the distal end portion with a flexible structure that anticipates and counteracts the harmful effects of plastic deformation. The flexible distal end is designed to deform in a controlled manner during balloon expansion, absorbing strain energy and preventing the transmission of excessive forces to the marker attachment regions. This preliminary structural adaptation prevents marker dislodgment while still enabling successful deployment.
Solution Approach 2:
The flexible distal end portion acts as a cushioning element that absorbs and dissipates strain energy generated during balloon expansion before it can reach the marker securement regions. This beforehand cushioning protects the markers from dislodgment forces while allowing the necessary plastic deformation to occur for proper scaffold deployment.
3Object-affected harmful factors
If thin-walled scaffold is used to reduce thrombogenicity, then biocompatibility is improved, but structural strength deteriorates under radial compressive forces
Solution Approach 1:
The patent applies local quality by creating a distal end portion with wall thickness and structural characteristics optimized for flexibility and low thrombogenicity, while the proximal portion maintains sufficient wall thickness and structural integrity for radial strength. This localized differentiation allows the scaffold to simultaneously achieve low thrombogenicity in the distal region and adequate radial strength in the proximal region for vessel support.
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.