Helical Anchor Deployment for Stent-Graft Vessel Penetration
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Solution Overview
Problem
Challenges exist in deploying anchors for stent-grafts due to tight vessel geometries, making it difficult to penetrate the stent graft and vessel wall effectively, especially when the anchor deployment is not normal to the vessel wall.
Innovation Solution
A helical anchor is provided in a relaxed state, with a distal portion superelastically deformed to protrude longitudinally during deployment, allowing it to pierce the prosthesis and vessel wall easily, and returning to its relaxed state after passage, ensuring better clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the anchor is deployed in a conventional relaxed state, then the deployment process is simple, but it is difficult to penetrate the stent graft and vessel wall effectively due to tight vessel geometries
Solution Approach 1:
The anchor transitions from a relaxed helical state during delivery to a deformed protruding state during penetration, and then to an expanded clamping state after penetration. This dynamic shape transformation enables the anchor to adapt to different operational phases: simple delivery, effective penetration, and secure anchoring, resolving the contradiction between operational simplicity and penetration effectiveness.
Solution Approach 2:
The anchor's physical parameters (shape, length, rigidity) are changed during deployment. The distal portion is superelastically deformed to protrude longitudinally, increasing its penetration capability. After penetrating the stent graft and vessel wall, the anchor returns to its relaxed state and expands to provide clamping force. These parameter changes enable effective penetration without requiring complex deployment mechanisms.
2Reliability
If the anchor is made rigid for better clamping, then the anchoring stability is improved, but it becomes difficult to deploy through tight vessel geometries
Solution Approach 1:
The anchor exhibits dynamic mechanical properties, being flexible during delivery to navigate tight vessel geometries and then becoming rigid through superelastic deformation to provide stable anchoring. The transition from flexible to rigid state occurs automatically during the deployment process, resolving the contradiction between deployability and anchoring stability.
Solution Approach 2:
The anchor is constructed as a flexible helical structure that can be compressed and deformed during delivery through tight vessel geometries. The flexible nature allows it to pass through the delivery catheter and navigate anatomical constraints, while still maintaining the capability to rigidify upon deployment for stable anchoring.
3Ease of operation
If the anchor protrudes longitudinally to facilitate piercing, then penetration effectiveness is improved, but the anchor structure becomes more complex
Solution Approach 1:
Only the distal portion of the anchor undergoes superelastic deformation to protrude longitudinally, while the proximal portion remains in its relaxed helical state. This localized deformation concentrates the penetration capability at the tip where it is needed, while maintaining the overall simplicity of the anchor structure. The local quality change enables effective penetration without requiring complex structural modifications throughout the entire anchor.
Data Source
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AI summary
In accordance with one embodiment, a helical anchor is provided in a relaxed state. During deployment, a distal portion of the helical anchor is superelastically deformed to protrude longitudinally. The longitudinally protruding distal portion of the helical anchor is longitudinally advanced to cause the distal portion to pierce a prosthesis and a vessel wall. The distal portion returns to the relaxed state after passing through the prosthesis and the vessel wall. By superelastically deforming the distal portion during deployment, it is easier to cause the anchor to penetrate the prosthesis and the vessel wall. Further, by having the anchor return to its relaxed state after passing through the prosthesis and vessel wall, better clamping of the prosthesis to the vessel wall is achieved.