Stent Barb Guard for Reduced Deployment Friction
Solution Overview
Problem
Existing endoluminal prostheses with barbs face significant frictional interference with deployment sheaths, increasing the operating effort due to direct contact between the barb tips and the sheath, especially when self-expanding or having exposed barbs.
Innovation Solution
A degradable barb guard, either dissolvable or frangible, is used to cover the distal tip of the barb, preventing contact with the sheath during deployment and degrading to expose the tip only after the stent is released, allowing engagement with the vessel wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barbs are exposed to engage the vessel wall, then anchoring effectiveness is improved, but frictional engagement with the sheath increases making deployment more difficult
Solution Approach 1:
A degradable guard is introduced as an intermediary element between the barb and the sheath during deployment. The guard covers the barb tip while passing through the sheath, then degrades to expose the barb for vessel wall engagement. This mediator temporarily prevents harmful friction during deployment while allowing the barb to function effectively after deployment.
Solution Approach 2:
The barb is pre-covered with a protective guard before deployment. This preliminary protective action prevents the barb from engaging the sheath during the deployment process, reducing friction and deployment effort. The guard is designed to degrade after deployment, allowing the barb to subsequently engage the vessel wall effectively.
2Ease of operation
If barbs are covered to reduce friction with the sheath, then deployment effort is reduced, but engagement with the vessel wall is compromised
Solution Approach 1:
The guard is designed with dynamic properties - it transitions from a protective state during deployment to a degraded state after deployment. The guard degrades in response to environmental changes (pH, enzymes, time) after the stent is released from the sheath, allowing the barb to become exposed and engage the vessel wall when needed.
Solution Approach 2:
The guard material undergoes parameter changes (chemical or physical degradation) after deployment. The degradation process changes the guard's structural integrity, allowing it to break down and expose the barb. This parameter change enables the system to transition from low-friction deployment mode to effective anchoring mode.
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 solution reduces the deployment effort by minimizing frictional engagement between the barb and the sheath, facilitating easier stent expansion and anchoring within the vessel while maintaining effective engagement with the vessel wall.
Implementation Method 1
the barb guard degrades by dissolving to expose the distal tip of the barb when the stent is placed in a vessel
Implementation Method 2
the barb guard degrades by breaking to expose the distal tip of the barb when the stent is placed in a vessel
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An endoluminal prosthesis is described and comprises a stent (40), At least one barb (42) secured to the stent, and a degradable barb guard (52) covering at least a portion of the barb and protecting the distal tip when the stent is in a compressed configuration. The barb guard (52) comprises a degradable structure that degrades to expose the distal tip of the barb when the stent is placed in a vessel. An endoluminal prosthesis deployment system comprising a sheath having a lumen and a prostesis within the sheath lumen is also described