Segmented Delivery Sheath for Heart Valve Kinking
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Solution Overview
Problem
Current percutaneous delivery systems for self-expanding stented prosthetic heart valves face challenges in accurately positioning and recapturing the valve due to the rigidity of the delivery sheath, which can kink when traversing tortuous vasculature like the aortic arch, making it difficult to deploy and reposition the valve correctly.
Innovation Solution
A delivery system with a capsule having a distal segment of greater outer diameter and radial stiffness than the proximal segment, designed to reduce kinking and facilitate recapture, allowing the prosthetic heart valve to be compressed and retained in a manner that accommodates the aortic arch's curvature without buckling, enabling precise deployment and repositioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the delivery sheath is made rigid to prevent buckling during delivery, then structural stability is improved, but the ability to traverse tortuous vasculature deteriorates
Solution Approach 1:
The delivery sheath is divided into multiple segments with different stiffness characteristics. The proximal segment has higher radial stiffness to prevent buckling, while the distal segment has lower radial stiffness to navigate tortuous vasculature, resolving the contradiction between structural stability and adaptability.
Solution Approach 2:
Different portions of the delivery sheath are assigned different mechanical properties. The proximal segment is designed with higher radial stiffness for structural support, while the distal segment is designed with lower radial stiffness for flexibility, allowing the sheath to simultaneously maintain stability and adapt to complex vascular pathways.
2Ease of operation
If the delivery sheath is made flexible to navigate the aortic arch, then ease of navigation is improved, but the ability to maintain position and prevent kinking deteriorates
Solution Approach 1:
The delivery sheath is segmented into proximal and distal portions with different stiffness characteristics. The proximal segment provides rigidity for positional stability and kink prevention, while the distal segment provides flexibility for navigation, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
The delivery sheath exhibits non-uniform mechanical properties along its length, with the proximal segment having higher radial stiffness for stability and the distal segment having lower radial stiffness for navigability, simultaneously achieving ease of operation and positional reliability.
3Stability of the object's composition
If the outer diameter of the delivery sheath is increased to reduce kinking, then structural stability is improved, but the ability to pass through access vessels deteriorates
Solution Approach 1:
The delivery sheath is divided into segments with different outer diameters. The proximal segment has a larger outer diameter to provide structural stability and prevent kinking, while the distal segment has a smaller outer diameter to facilitate passage through access vessels, resolving the contradiction between structural stability and access vessel compatibility.
Solution Approach 2:
The delivery sheath has non-uniform outer diameter along its length, with the proximal segment having larger diameter for stability and the distal segment having smaller diameter for access, simultaneously achieving structural stability and vascular compatibility.
Data Source
Figure 1A~1B
Figure 2
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AI summary
A device for percutaneously repairing a heart valve of a patient including a self - expanding, stented prosthetic heart valve (20) and a delivery system (40). The delivery system includes delivery sheath (42) slidably receiving an inner shaft forming a coupling structure. A capsule of the delivery sheath includes a distal segment (60) and a proximal segment (62). An outer diameter of the distal segment is greater than that of the proximal segment. An area moment of inertia of the distal segment can be greater than an area moment of inertia of the proximal segment. Regardless, an axial length of the distal segment (LD) is less than the axial length of the prosthesis (LP). In a loaded state, the prosthesis engages the coupling structure and is compressively retained within the capsule. The capsule is unlikely to kink when traversing the patient's vasculature, such as when tracking around the aortic arch, promoting recapturing of the prosthesis.