Self-Expanding Stent-Graft with Variable Stiffness for Aortic Sealing
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Solution Overview
Problem
Current stent-grafts face challenges in treating abdominal aortic aneurysms, particularly short-neck infrarenal, juxtarenal, and suprarenal aneurysms, due to insufficient non-aneurysmal neck length, leading to blood leakage and difficulty in sealing and directing flow into branch vessels like the renal arteries and superior mesenteric artery.
Innovation Solution
A self-expanding main vessel stent-graft with a trunk portion, bifurcated portion, and variable stiffness stents that include scallops and couplings to accommodate branch vessels, allowing for secure placement and blood flow direction without occluding critical arteries, and featuring a design that can be used off-the-shelf for various anatomies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent-graft is deployed to seal against the aorta wall, then sealing effectiveness is improved, but blood leakage into the space between the graft and vessel wall occurs due to misalignment with branch arteries
Solution Approach 1:
The stent-graft is segmented into multiple sections including a main body and lateral extensions that can be independently positioned. The lateral extensions are designed to align with branch artery ostia, creating separate sealing zones that prevent blood leakage while maintaining patency of both the main aorta and branch vessels.
Solution Approach 2:
The lateral extensions act as intermediary structures between the main stent-graft body and the branch arteries. These extensions provide a transition zone that directs blood flow into the branch vessels while maintaining the seal between the graft and aortic wall, preventing blood from leaking into the space between the graft and vessel wall.
2Reliability
If the stent-graft extends across the origin of branch arteries, then sealing is improved, but blood flow into branch vessels is blocked
Solution Approach 1:
The stent-graft is divided into a main body portion and separate lateral extension portions. The lateral extensions are specifically designed to align with and preserve blood flow into branch arteries while the main body provides the primary seal. This segmentation allows the sealing function and blood flow preservation function to be performed by different structural elements.
Solution Approach 2:
Different portions of the stent-graft have different structural qualities optimized for their specific functions. The main body has a structure optimized for sealing against the aortic wall, while the lateral extensions have a structure optimized for aligning with and preserving blood flow into branch arteries. This local differentiation of structural properties resolves the contradiction between sealing and maintaining branch vessel patency.
3Manufacturing precision
If custom-designed stent-grafts are used for specific anatomies, then precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The stent-graft is designed with universal applicability through its modular structure consisting of a main body and configurable lateral extensions. The device can be adapted to treat various types of abdominal aortic aneurysms (infrarenal, juxtarenal, suprarenal) and accommodate different anatomical variations without requiring custom design for each patient, thereby reducing manufacturing time and cost while maintaining anatomical matching precision.
Solution Approach 2:
The stent-graft incorporates dynamic elements that allow it to adapt to different anatomical configurations. The lateral extensions can be positioned and configured to match various branch artery orientations and locations, enabling a single device design to serve multiple anatomical scenarios without requiring custom manufacturing for each case.
Data Source
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AI summary
A self-expanding main vessel stent-graft includes a trunk portion configured for placement within the abdominal aorta and a bifurcated portion configured for placement above the aortic bifurcation of the common iliac arteries. The trunk portion includes a proximal end section having an anchor stent and a seal stent that accommodates a scallop or open-top fenestration; a suprarenal body section having at least one stent of variable stiffness to accommodate branch vessel prosthesis deployed alongside the main vessel stent-graft; a branch connection section having opposing couplings for connecting the main vessel stent-graft to branch vessel prostheses deployed within the renal arteries; an infrarenal body section having at least one stent of uniform stiffness; and a transition section for transitioning into the bifurcated portion. The main vessel stent-graft is configured to treat short-neck infrarenal, juxtarenal, and/or suprarenal aneurysms in a wide range of patient anatomies.