TAPAS Graft Sheath Enveloping Self-Expanding Stent
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Solution Overview
Problem
Current stent-graft technologies face challenges in minimally invasive, controlled introduction and accurate positioning of a folded self-expanding prosthesis within a blood vessel, particularly in the aortic region, and in separating the prosthesis from the guide while removing the guide from the vessel.
Innovation Solution
A Trans Aortic Proximal Aortic Stent-Graft (TAPAS Graft) with a tube-like sheath enveloping the folded prosthesis from both inside and outside, featuring a releasable fixation mechanism using a cord-splint mechanism for precise deployment and separation from the guide, allowing for antegrade operative processes in treating various aortic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a folded self-expanding prosthesis is introduced via a guide catheter, then minimally invasive access is achieved, but controlled deployment and accurate positioning become difficult
Solution Approach 1:
The patent introduces a guide catheter as an intermediary device that facilitates the introduction of the folded prosthesis through minimally invasive access. The guide catheter serves as a mediator between the delivery system and the target vessel, enabling controlled navigation while maintaining the benefits of minimal invasion. This resolves the contradiction by providing a structured pathway that improves positioning accuracy without sacrificing ease of access.
Solution Approach 2:
The prosthesis is pre-folded and pre-positioned within the guide catheter before introduction. The anchor mechanism is pre-configured to engage with the vessel wall at the intended deployment site. This preliminary preparation allows for accurate positioning to be achieved during deployment, resolving the contradiction between minimally invasive access and positioning precision.
2Ease of operation
If the prosthesis is kept folded during insertion, then minimally invasive introduction is enabled, but controlled unfolding from proximal to distal end becomes complex
Solution Approach 1:
The prosthesis transitions from a static folded state during insertion to a dynamic self-expanding state during deployment. The self-expanding特性 of the prosthesis allows it to automatically unfold from proximal to distal end when released from the guide catheter, eliminating the need for complex external actuation mechanisms. This resolves the contradiction by using the inherent dynamic properties of the prosthesis material to achieve controlled unfolding without adding system complexity.
Solution Approach 2:
The prosthesis is designed to self-unfold and self-deploy once released from the guide catheter. The self-expanding mechanism inherently controls the unfolding sequence from proximal to distal end without requiring external control systems. This self-service capability resolves the contradiction by simplifying the deployment mechanism while maintaining controlled, sequential expansion.
3Ease of operation
If the prosthesis is separated from the guide by a release mechanism, then guide removal is facilitated, but the release mechanism complexity increases
Solution Approach 1:
The release mechanism is designed to extract or separate the prosthesis from the guide catheter in a controlled manner. Once the prosthesis is deployed, the release mechanism facilitates the extraction of the guide catheter from the vessel, simplifying the removal process. This resolves the contradiction by providing a dedicated extraction function that simplifies guide removal without requiring overly complex mechanisms.
Solution Approach 2:
The guide catheter and release mechanism are designed as single-use, disposable components. The guide catheter is intentionally left in the vessel temporarily to aid deployment, then removed via the release mechanism. This disposable approach simplifies the release mechanism design compared to reusable systems that would require complex sterilization and retrieval mechanisms, resolving the contradiction between ease of removal and mechanism complexity.
4Extent of automation
If the prosthesis is self-expanding, then automated deployment is achieved, but precise control over deployment timing and position becomes difficult
Solution Approach 1:
The guide catheter serves as an intermediary that controls the timing and position of prosthesis deployment. The self-expanding prosthesis remains constrained within the guide catheter during navigation, and deployment is triggered only when the guide catheter is positioned at the target site. This intermediary control resolves the contradiction by maintaining automated self-expansion while adding precise spatial and temporal control through the guide catheter positioning system.
Solution Approach 2:
The guide catheter is positioned at the desired deployment location before releasing the prosthesis. This preliminary positioning action ensures that when the self-expanding prosthesis is released, it deploys at the correct location and timing. The anchor mechanism is also pre-configured to engage with the vessel wall at the intended site, further ensuring precise deployment control while maintaining automated expansion.
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
Enables controlled, minimally invasive introduction and precise positioning of the stent-graft prosthesis, ensuring accurate deployment and removal, suitable for treating conditions like aortic dissections, aneurysms, and calcifications, with the ability to unfold from proximal to distal, ensuring exact placement and efficient surgical outcomes.
Implementation Method 1
a folded, self-expanding prosthesis
Data Source
AI summary
A trans-aortic proximal aortic stent graft [TAPAS graft] for introducing into a blood vessel. A a tubular sheath which encases a folded self-expanding stent from the inside as well as from the outside such that a sheath outer wall of the sheath lies against the self-expanding stent from the outside and a sheath inner wall lies against the self-expanding stent from the inside and keeps the self-expanding stent folded. The self-expanding stent is surrounded by the sheath at the distal end in the transition from the sheath inner wall to the sheath outer wall, and the self-expanding stent is provided with an anchor at the proximal end. Also, a method for using a trans-aortic proximal aortic stent graft [TAPAS graft].