Flexible Stent Design for Prosthetic Heart Valve Stress Reduction
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Solution Overview
Problem
Current collapsible prosthetic heart valves face issues such as perivalvular leakage, valve migration, and conduction system disruption due to uneven calcification and native stenotic leaflets, which require a stent that exerts radial force without harming nearby anatomy and employs additional anchoring features to reduce leaflet/stent stresses.
Innovation Solution
A prosthetic heart valve design featuring a stent with a plurality of cells, support struts, and support posts that are connected in a way to allow flexibility, reducing stress on the valve leaflets by distributing radial force and using anchoring features that do not rely on excessive force, thereby minimizing adverse clinical outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stent exerts excessive radial force to hold open stenotic leaflets, then the valve remains stable and prevents perivalvular leakage, but nearby anatomy and physiology are harmed
Solution Approach 1:
The stent employs a flexible design with cells and struts that can deform and adapt to the native valve anatomy, distributing radial force more evenly across the tissue rather than concentrating it at specific points, thereby preventing damage to nearby anatomy while maintaining valve stability
Solution Approach 2:
The stent utilizes shape memory alloy properties that allow it to change its radial force output based on temperature and mechanical conditions, enabling it to exert sufficient force to hold open stenotic leaflets while automatically reducing force when tissue resistance increases, thus preventing anatomical damage
2Strength
If a rigid stent is used to provide structural support, then the valve framework is strong and stable, but stress on the valve leaflets increases leading to tissue failure
Solution Approach 1:
The stent incorporates flexible cellular structures and thin-walled struts that provide sufficient structural support while allowing the framework to deform elastically under load, thereby reducing peak stresses transmitted to the valve leaflets and preventing tissue failure at the commissures
Solution Approach 2:
The stent design allows dynamic movement and deformation of its structural elements during valve cycling, enabling the framework to absorb and redistribute mechanical stresses rather than transmitting them rigidly to the leaflet attachment points, thus reducing leaflet stress while maintaining structural integrity
3Reliability
If additional anchoring features are added to reduce valve migration, then the valve becomes more securely positioned, but the device complexity increases
Solution Approach 1:
The stent's cellular structure serves multiple functions simultaneously: it provides structural support, distributes radial force to prevent anatomical damage, and creates frictional engagement with the native valve tissue to prevent migration, thereby achieving secure positioning without adding separate anchoring components that would increase device complexity
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 reduces stress on the valve leaflets by up to 80% and minimizes adverse clinical outcomes like perivalvular leakage and valve migration, enhancing the durability and functionality of the prosthetic heart valve.
Implementation Method 1
the optimal valve would seal and anchor to the cardiac tissue adequately without the need for excessive radial force that could harm nearby anatomy and physiology
Implementation Method 2
a flexible stent greatly reduces stress on the valve,' which was as large as a 90% reduction of the closing stresses near the commissures when flexibility and coaptation area were maximized
Implementation Method 3
a flexible stent greatly reduces stress on the valve
Data Source
AI summary
A prosthetic heart valve includes a stent having an expanded condition and a collapsed condition. The stent includes a plurality of distal cells, a plurality of proximal cells, a plurality of support struts coupling the proximal cells to the distal cells, and at least one support post connected to a plurality of proximal cells. The proximal cells are longitudinally spaced apart from the distal cells. Various strut configurations and connections of the struts to the proximal cells and of the proximal cells to the support post improve stent flexibility and reduce stress in the valve leaflets.