Microporous Shape Memory Vascular Graft for Neointimal Hyperplasia
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Solution Overview
Problem
Existing vascular access methods, such as arteriovenous fistulas and grafts, suffer from high failure rates due to neointimal hyperplasia and lack of positive remodeling, with current therapeutic approaches showing limited clinical success due to inappropriate material selection and geometric design.
Innovation Solution
A biodegradable polymeric scaffold with specific pore sizes and spacings, composed of crosslinkable shape memory polymers, is applied periadventitially to induce neovascularization and tissue ingrowth, providing mechanical compliance and localized therapeutic delivery to prevent neointimal formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vascular access methods (AVFs and AVGs) are used, then vascular access is established, but high failure rates occur due to neointimal hyperplasia and lack of positive remodeling
Solution Approach 1:
The patent employs a microporous shape memory polymer implant with controlled pore sizes (5-50 micrometers) and porosity (50-90%) to promote tissue ingrowth and neovascularization. The porous structure allows cellular infiltration and tissue integration while maintaining mechanical support, directly addressing the neointimal hyperplasia problem by facilitating beneficial tissue formation rather than obstructive neointima development.
Solution Approach 2:
The patent utilizes shape memory polymers that undergo phase transitions at specific temperatures to change from a temporary compressed state to a permanent expanded state. This parameter change enables the implant to be delivered in a compact form and then self-expand at the implantation site to provide optimal mechanical support and surface area for tissue integration, improving vascular access patency.
2Object-generated harmful factors
If external stents are used to reduce neointimal hyperplasia through promotion of neovascularization, then some benefit is achieved, but limited clinical success occurs due to inappropriate material selection (nondegradable, too stiff) and geometric design
Solution Approach 1:
The patent employs composite material strategies by combining shape memory polymer matrices with porous structures and potentially incorporating bioactive agents or endothelial cell coatings. This composite approach provides both mechanical support and biological functionality, enabling the implant to promote neovascularization while avoiding the limitations of nondegradable, stiff materials used in conventional stents.
Solution Approach 2:
The shape memory polymer undergoes temperature-induced phase transitions to change mechanical properties from soft and compliant during delivery to stiff and supportive after deployment. This dynamic parameter change allows the implant to adapt to different physiological conditions and provides mechanical compliance that better matches native vasculature, improving adaptability and reducing foreign body response.
3Reliability
If microporous shape memory polymer implant is used, then neovascularization and tissue ingrowth are promoted, but device complexity increases
Solution Approach 1:
The shape memory polymer implant performs self-service by automatically transforming from a compressed delivery state to an expanded functional state through temperature-induced phase transitions after implantation. This self-actuating mechanism eliminates the need for complex deployment mechanisms, balloons, or external manipulation devices, reducing overall device complexity while maintaining the microporous structure for tissue ingrowth.
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 scaffold promotes favorable cellular responses, reducing neointimal hyperplasia and enhancing vascular access patency by promoting outward remodeling and minimizing inflammation, thus improving clinical outcomes.
Implementation Method 1
The biodegradable polymeric scaffold may be configured to have a melting temperature and be moldable from a first shape to a second shape by an external force when the melting temperature is met or exceeded
Implementation Method 2
The scaffold may have a pore size of about 400 μm-1200 μm and a pore spacing of about 100 μm to about 750 μm
Data Source
AI summary
The present invention relates generally to shape memory polymer devices that are porous. The porosity of the device may generate advantageous neovascularization, decrease inflammation, and decrease fibrosis. The device may include a surface having a pore size of 400 μm-1200 μm and a pore spacing of about 100 μm to about 750 μm.