Double-Walled Fixed-Length Stent for Adjustable Vessel Constriction
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Solution Overview
Problem
Current surgical pulmonary artery banding procedures face challenges in accurately adjusting the optimal diameter of the pulmonary artery, risk of band migration, vessel hardening, and difficulty in implanting devices in adults with left ventricle failure, necessitating a minimally-invasive and adjustable medical apparatus for treating congestive heart failure.
Innovation Solution
A stent-like medical apparatus with a first and second tubular wall, firmly connected at their edges, allowing partial constriction to form a diametrical reducer, which can be deployed via a catheter and adjusted to reduce vessel diameter, using materials like Nitinol, stainless steel, or polymers, and comprising section elements that deform to maintain longitudinal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stent is delivered in a compressed state through a catheter and then expanded at the target site, then the stent can be delivered through small access vessels, but the stent may become stuck in the compressed state or fail to expand properly
Solution Approach 1:
The stent is divided into multiple segments or sections that can expand independently or in sequence. This segmentation allows the stent to transition smoothly from compressed to expanded state, reducing the risk of getting stuck and improving expansion reliability while maintaining ease of delivery through compressed catheters
Solution Approach 2:
The stent employs dynamic expansion mechanisms that allow progressive transformation from compressed to expanded state. The stent structure includes movable components that can transition between states in a controlled manner, ensuring reliable expansion while maintaining deliverability through small access vessels
2Length of moving object
If a stent is designed to be expandable from a compressed state, then the stent can be delivered through small catheters, but the mechanism for expansion adds complexity to the device
Solution Approach 1:
The stent is designed with a nested structure where the expanded stent can be contained within a delivery catheter in a compressed state. The stent framework includes nested components that allow compact storage during delivery while enabling expansion at the target site, reducing catheter size requirements without excessive complexity
Solution Approach 2:
The stent utilizes dimensional transformation by compressing the stent structure along one dimension (radial compression) to fit within the catheter, then expanding back in that dimension at the target site. This dimensional approach allows small catheter access while maintaining a relatively simple stent structure without complex expansion mechanisms
3Stability of the object's composition
If the stent is made with a fixed length design, then the stent provides consistent positioning, but the stent cannot adapt to different vessel sizes or locations
Solution Approach 1:
The stent employs local quality variations where different sections of the stent have different properties. The stent includes proximal and distal portions with specific characteristics that enable adaptability to different vessel sizes and locations while maintaining overall fixed length and positioning stability. Different segments can expand to different degrees or have different radial strengths to match local vessel requirements
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 apparatus effectively reduces vessel diameter, improving left ventricle function by maintaining optimal constriction and reducing symptoms of congestive heart failure, including increased ejection fraction and decreased end diastolic pressure.
Implementation Method 1
the outer tube is expandable from an unexpanded configuration in which the outer tube assumes a generally cylindrical shape to an expanded configuration in which the outer tube defines a lumen
Implementation Method 2
the inner tube is expandable from an unexpanded configuration in which the inner tube assumes a generally cylindrical shape to an expanded configuration in which the inner tube defines a lumen
Implementation Method 3
a resilient member positioned within the inner tube and configured to bias the inner tube to the expanded configuration
Implementation Method 4
a locking mechanism configured to constrain the inner tube in the expanded configuration against the outer tube
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A new medical apparatus for deployment within an anatomical blood vessel and methods of use thereof The apparatus comprising: a first tubular wall; and a second tubular wall, placed within the first tubular wall; wherein the first and second tubular walls are firmly connected at their edges, therefore restricted to have same overall longitudinal length; and wherein the second tubular wall is configured to be partially constricted towards its inner radial axis, while maintaining its overall longitudinal length.