Biodegradable Stent Radial Force via Shape Memory Expansion
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Solution Overview
Problem
Biodegradable stents lack sufficient mechanical strength and are prone to cracking due to inadequate expansion and contraction processes, which affects their effectiveness in supporting blood vessels.
Innovation Solution
A shape memory extending method for biodegradable stents involves using a compliant balloon catheter to uniformly expand and contract the stent, altering the molecular array of the polymer to enhance radial force and reduce cracking, by applying pressure within specific temperature and pressure ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a biodegradable stent is mechanically expanded using an inflatable balloon, then the stent can be deployed in the vessel conduits, but the stent lacks sufficient mechanical strength and is prone to cracking
Solution Approach 1:
The patent applies parameter changes by controlling temperature and pressure during expansion to alter the molecular array state of the polymer material. This transforms the physical and mechanical properties of the stent, enhancing its strength and crack resistance without changing the material composition itself.
Solution Approach 2:
The patent utilizes phase transitions of the polymer material through controlled heating and pressurization. The stent undergoes transitions between different molecular states (crystalline, amorphous, gel phases) that fundamentally change its mechanical properties, enabling it to achieve both flexibility for deployment and strength for support.
2Force
If the stent is expanded to increase radial force, then the stent can better support the blood vessel, but the number of cracks increases due to inadequate expansion control
Solution Approach 1:
The patent employs feedback control through controlled heating and pressurization systems that monitor and adjust expansion parameters in real-time. This ensures uniform expansion throughout the stent structure, preventing localized stress concentrations that would lead to cracking while achieving the desired radial force.
Solution Approach 2:
The patent applies preliminary action by pre-heating and pre-pressurizing the stent material before full expansion. This prepares the polymer matrix to undergo uniform molecular rearrangement, ensuring that when expansion occurs, it proceeds evenly throughout the structure rather than creating stress concentration points.
3Device complexity
If a non-compliant balloon is used for stent expansion, then the expansion process is simpler, but the stent cannot be uniformly extended leading to folding and cracks
Solution Approach 1:
The patent applies dynamics by using a compliant balloon that can dynamically adapt its shape and pressure distribution during expansion. The balloon material itself undergoes deformation to match the stent's expansion pattern, ensuring uniform force distribution across the stent structure and preventing folding or localized cracking.
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 method significantly increases the radial force of the stent while reducing the number of cracks, ensuring effective support and durability of the stent within the blood vessel.
Implementation Method 1
a shape memory extending method of a biodegradable stent... radial force of a biodegradable stent largely increases through a shape memory extending process... a molecule array state of a polymer is changed
Data Source
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AI summary
The present invention relates to a biodegradable stent and a shape memory extending method thereof. According to an exemplary embodiment of the present invention, radial force of a biodegradable stent may be largely increased through the shape memory extending method of the biodegradable stent and the number of cracks may be decreased after crimping and stent inflation.