Sealing Stent Loop Constriction for Aortic Curve Conformance
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Solution Overview
Problem
Existing stent grafts face issues with proximal sealing stents tilting inwardly, particularly in extreme cases, due to the curvature of the aorta, leading to poor conformance and potential deployment failures.
Innovation Solution
A diameter reducing loop arrangement is implemented, comprising first and second diameter reducing loop elements that pass circumferentially around the sealing stent, overlapping its apices, and are constrained by a release wire to create a conical or frustoconical shape, reducing the dependence on cannula positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing stent is used at the proximal end of the graft body to treat aortic aneurysms, then sealing effectiveness is improved, but the sealing stent tends to tilt inwardly due to aortic curvature, causing poor conformance
Solution Approach 1:
The diameter reducing loop arrangement is pre-configured on the sealing stent before deployment. The loops are initially in a relaxed state allowing the stent to expand to its full circular shape during deployment, then can be actively constricted afterward to create the desired conical configuration for improved conformance to the aortic curve
Solution Approach 2:
The diameter reducing loop arrangement transforms the static sealing stent into a dynamically adjustable structure. The loops can transition from an expanded circular configuration during deployment to a constricted conical configuration after deployment, allowing the stent to adapt its shape to match the aortic curvature and improve conformance
2Shape
If the sealing stent is constrained to adopt a conical shape to improve conformance, then conformance to aortic curve is improved, but the stent may not deploy properly in straight aorta sections
Solution Approach 1:
The diameter reducing loop arrangement allows the sealing stent to dynamically change its configuration. During deployment, the loops remain relaxed allowing the stent to expand to its full circular shape for proper deployment in straight aorta sections. After successful deployment, the loops can be actively constricted to create the conical shape needed for improved conformance to curved aortas
Solution Approach 2:
The invention changes the geometric parameters of the sealing stent after deployment. The diameter reducing loops are constricted to reduce the diameter of the distal apices of the sealing stent, transforming it from a circular to a conical shape. This parameter change allows the stent to adapt to different aortic geometries while maintaining reliable deployment
Data Source
AI summary
Disclosed is a stent graft, including a graft body, a sealing stent at the proximal end of the graft body and completely overlapped by the graft body, and a diameter reducing loop arrangement. The sealing stent includes proximal apices at a proximal end thereof and distal apices at a distal end thereof. The diameter reducing loop arrangement includes a loop element. The loop element includes a first end, a second end, and a strand section from the first end to the second end. The first end is attached to the distal end of the sealing stent. The loop element is configured to pass circumferentially around the distal end of the sealing stent and have a release wire pass through a loop at the second end. The diameter reducing loop arrangement is configured to constrict the distal apices of the sealing stent and cause the sealing stent to adopt a substantially conical or frustoconical shape.