Bioresorbable Venous Stent for Chronic Venous Insufficiency
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Solution Overview
Problem
Current intravascular metal stents designed for arterial applications are inadequate for venous systems, leading to issues such as inadequate mechanical dimensions, high risks of restenosis and thrombosis, poor patency, and disquieting tendencies towards migration, which complicates the treatment of venous diseases like chronic venous insufficiency, venous thromboembolism, and hemodialysis access failures.
Innovation Solution
Development of a balloon-expandable, bioresorbable venous stent with high radial force, made from materials like poly(L-lactic acid) or polyglycolic acid, providing temporary rigid support to maintain vein patency and gradually becoming flexible as it dissolves, allowing for adaptive vascular remodeling and reducing inflammation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal stents designed for arterial applications are used in the venous system, then structural support is provided, but high risks of restenosis and thrombosis occur
Solution Approach 1:
The patent changes the material parameter from permanent metal to bioresorbable polymer, transforming the stent from a permanent structural support to a temporary one that degrades over time. This parameter change resolves the contradiction by providing sufficient structural support during the critical healing period while eliminating long-term foreign body presence that causes restenosis and thrombosis.
Solution Approach 2:
The patent employs a disposable, short-living stent made of bioresorbable material that performs its structural support function temporarily and then degrades. This approach provides the necessary mechanical strength during the acute phase while avoiding the long-term complications associated with permanent metal stents, effectively resolving the reliability issue.
2Strength
If metal stents are used to maintain vein patency, then immediate structural support is achieved, but migration into the right atrium occurs
Solution Approach 1:
The patent changes the mechanical parameter of the stent from rigid permanent metal to flexible temporary polymer. The bioresorbable stent provides sufficient radial support force initially but gradually softens and loses strength as it degrades, reducing the risk of migration while maintaining patency during the critical period.
Solution Approach 2:
The patent introduces a dynamic characteristic to the stent through its bioresorbable nature. The stent's mechanical properties change over time - providing high radial support immediately after deployment and gradually transitioning to a softer, more compliant state as it degrades, thereby adapting to the venous environment and reducing migration risk.
3Strength
If compression hosiery is used to treat chronic venous insufficiency, then mechanical limitation of venous dilation is achieved, but patient compliance is poor
Solution Approach 1:
The patent extracts the need for external compression devices by placing a self-contained structural support directly within the vein. The intravascular stent provides the mechanical support function internally, eliminating the need for external compression hosiery that patients find uncomfortable and difficult to comply with.
Solution Approach 2:
The patent enables the vein to support itself through the implanted stent that provides internal structural reinforcement. The stent serves the vein's support needs autonomously without requiring external assistance from compression garments, thereby improving ease of operation and patient compliance.
4Duration of action of stationary object
If permanent metal stents are implanted in veins, then long-term structural support is provided, but chronic foreign body reaction and inflammation occur
Solution Approach 1:
The patent employs a temporary, short-living stent made of bioresorbable material that provides structural support only during the period when it is most needed - the acute and subacute phases of vein repair. Once this period passes, the stent degrades and is eliminated, removing the source of chronic foreign body reaction and inflammation while having provided sufficient support during the critical healing window.
Solution Approach 2:
The patent changes the temporal parameter of structural support from permanent to temporary. The bioresorbable stent provides structural support for a limited duration that matches the physiological healing timeline, then degrades into harmless byproducts. This parameter change resolves the contradiction by providing adequate support when needed while eliminating the source of chronic inflammation.
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 bioresorbable stent effectively maintains vein patency, reduces restenosis, and allows for adaptive remodeling, addressing the limitations of traditional metal stents by providing sustained support without long-term foreign body reaction, facilitating imaging and surveillance during follow-up.
Implementation Method 1
The stent elements are formed from a bioresorbable polymer material
Implementation Method 2
gradually becoming flexible as it dissolves
Data Source
AI summary
A venous stent may be used to maintain or enhance patency of a blood vessel. By using multiple, separate stent elements that are balloon expandable, the multi-element stent may be stronger than a traditional self-expanding stent but may also be more flexible, due to its multiple-element configuration, than a traditional balloon-expandable stent. The stent elements are formed from a bioresorbable polymer material. The stent elements may have thick and/or wide struts and may be deployed oversized so as to overcome venous elastic recoil and anatomic compression.