Asymmetric Stent Strut Geometry for Laminar Flow
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Solution Overview
Problem
Conventional stents suffer from turbulence-induced deposits and reduced radial strength due to their strut designs, leading to vascular constriction and increased risk of restenosis, particularly at the proximal ends.
Innovation Solution
A stent design with struts featuring a directional component in the radial circumferential direction, where the luminal surface is asymmetrically convex and only curved in the longitudinal direction, optimized for laminar blood flow, and processed using a particle jet method to round luminal edges, reducing turbulence and maintaining radial strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the stent has small wall thicknesses to ensure sufficient flow cross section, then the flow cross section is improved, but the radial strength is reduced
Solution Approach 1:
The strut cross-section is designed with asymmetric curvature where the luminal surface is curved to promote laminar flow while the mural surface remains straight or has minimal curvature. This asymmetry allows the strut to maintain sufficient radial strength through the mural surface while optimizing the luminal surface for fluid dynamics, resolving the contradiction between flow cross-section requirements and radial strength needs.
2Ease of manufacture
If the struts have rectangular cross section to maintain structural simplicity, then the manufacturing is improved, but turbulence occurs in the blood stream
Solution Approach 1:
The luminal surface of the strut is curved with a specific radius of curvature to eliminate sharp edges that cause turbulence. This curvature transforms the rectangular cross-section into a shape with rounded luminal surfaces, promoting laminar blood flow while maintaining manufacturing feasibility through controlled deformation processes.
3Object-affected harmful factors
If the mural surface is curved to reduce vessel wall penetration, then the vessel injury is improved, but the axial section modulus is reduced
Solution Approach 1:
Different surfaces of the strut are given different geometric properties: the luminal surface is curved to optimize fluid flow, while the mural surface is kept straight or minimally curved to maintain structural strength and axial section modulus. This local differentiation allows each surface to be optimized for its specific function without compromising the other.
4Ease of manufacture
If the luminal surface is symmetrically curved to optimize flow, then the manufacturing is improved, but turbulence still occurs and deposits form
Solution Approach 1:
The strut cross-section employs asymmetric curvature where the luminal surface has a specific curvature radius optimized for laminar flow, while the mural surface has minimal or no curvature. This asymmetric design creates a streamlined profile that effectively guides blood flow and prevents turbulence-induced deposits, overcoming the limitations of symmetric curvature designs.
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
The design minimizes vascular constriction, promotes laminar blood flow, reduces deposits, and enhances endothelialization, while maintaining sufficient radial and bending strength to adapt to vessel movements.
Implementation Method 1
processed using a particle jet method to round luminal edges
Data Source
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AI summary
The stent (100) has a pipe like gitter structure (110) including struts (200), where a longitudinal section (220) with direction components extends from the struts in a radial circumferential direction of the stent. A mural longitudinal section surface directed towards an outerside of the stent is only curved around a longitudinal axis (150) of the stent. An intraluminal longitudinal section surface directed towards an innerside of the stent includes a curvature such that a cross-section of the struts is flow technically optimized. The curvature is in an asymmetrical convex shape. Independent claims are also included for the following: (1) a method for manufacturing a stent (2) a device for manufacturing a stent.