Flexible Stent Wavy-Cell Design Suppresses Axial Shortening
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Solution Overview
Problem
Conventional stents with open cell structures face issues of strut protrusion during bending, leading to tissue damage and thrombus formation, and experience shortening during expansion, making them difficult to deploy and increasing the risk of stress concentration on blood vessel walls.
Innovation Solution
A flexible stent design featuring a wavy-line pattern with V-shaped elements and connection elements that alternate in direction, reducing strut protrusion and minimizing axial shortening, while maintaining conformability and adhesion to the blood vessel wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a stent with an open cell structure is used to achieve high conformability, then the stent can flexibly adapt to tortuous tubular organs, but the strut protrudes radially outward when bending, causing tissue damage and thrombus formation
Solution Approach 1:
The patent employs a wavy-line pattern consisting of V-shaped elements with alternating apex orientations, creating a curved, serpentine structure that allows the stent to flex and conform to bent blood vessels without causing strut protrusion. The curved geometry distributes bending stresses along the wave pattern rather than concentrating them at rigid corners.
Solution Approach 2:
The patent modifies the geometric parameters of the cell structure by using a specific wavy-line pattern with controlled wave amplitude and wavelength. This parameter optimization ensures that when the stent bends, the struts follow the curved path of the wave pattern rather than protruding radially outward, thus maintaining conformability while preventing tissue damage.
2Adaptability or versatility
If a stent with an open cell structure is used to achieve high conformability, then the stent can adapt to complex vessel structures, but adhesion to the blood vessel wall deteriorates, generating spaces that cause thrombus
Solution Approach 1:
The wavy-line pattern creates a smoothly curved surface that can conform to the contours of the blood vessel wall, maximizing contact area and adhesion. The alternating V-shaped elements ensure continuous contact along the vessel wall even when the vessel is bent, preventing gaps that could lead to thrombus formation.
3Adaptability or versatility
If a stent with an open cell structure is used to achieve high conformability, then the stent can flexibly bend in the axial direction, but shortening occurs during expansion, making deployment difficult and causing stress concentration
Solution Approach 1:
The wavy-line pattern with alternating V-shaped elements creates a structure where the wave crests and troughs distribute expansion forces uniformly along the axial direction. This curved geometry allows the stent to expand radially while the wave pattern absorbs axial shortening through controlled deformation of the V-shapes, preventing stress concentration at any single location.
Data Source
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AI summary
Provided is a flexible stent in which a free end strut does not tend to project outside when the stent is bent and shortening can be suppressed at the time of expansion of the stent. The flexible stent includes annular bodies (13) having a wavy line pattern and connection elements (15) that connect the annular bodies (13). The wavy line pattern is formed by V-shaped elements (17), in which two leg parts (171) are joined by an apex part (172), being connected in a state where the apex parts (172) alternately face opposite directions in an axial direction. A bending direction of one end part (151) of the connection element (15) and a bending direction of another end part (151) thereof are opposite to one another. The end part (151) of the connection element (15) is connected to a portion other than the apex part (172) of the V-shaped element (17) of the adjacent annular body (13) with the end part (151) of the connection element (15) being extended in a direction different from the direction in which the leg part (171) extends. When viewed in a radial direction (RD), the direction in which an intermediate part (152) of the connection element extends is oblique to the axial direction (LD). One of the two leg parts (171) extends along the intermediate part (152) of the connection element (15).