Mitral Valve Stent Pivoting Nested Cells for Secure Anchoring
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Solution Overview
Problem
Conventional collapsible heart valves face challenges in securing themselves within the native valve annulus, often resulting in either tissue damage from excessive radial force or displacement due to insufficient anchoring, particularly in mitral valve replacements, where a low profile is required to avoid interfering with surrounding tissue structures.
Innovation Solution
The design incorporates a collapsible and expandable stent with nested cells that pivot to create a clamping mechanism, utilizing shape-memory alloys and connecting struts to securely anchor the valve by rotating and reverting to a shape-set configuration, ensuring stable positioning within the native valve annulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional collapsible heart valves are expanded to secure themselves within the native valve annulus, then anchoring strength is improved, but tissue damage occurs due to excessive radial force
Solution Approach 1:
The stent is divided into multiple cells with nested second cells within first cells. Each cell can independently pivot and engage tissue, distributing the anchoring force across multiple localized points rather than applying excessive radial force uniformly, thereby reducing tissue damage while maintaining securement.
Solution Approach 2:
The second cells are configured to pivot about connecting struts relative to the first cells, creating a dynamic clamping mechanism. This pivoting action allows the stent to adapt to the native valve annulus geometry and secure tissue between cells during deployment, providing secure anchoring without requiring excessive expansion force that would cause tissue damage.
2Stability of the object's composition
If conventional collapsible heart valves are expanded to provide secure anchoring, then displacement is reduced, but the profile increases interfering with surrounding tissue structures
Solution Approach 1:
Second cells are nested within the open spaces of first cells, creating a compact configuration when collapsed for delivery. Upon deployment, the nested cells pivot outward to engage tissue, providing stable anchoring while maintaining a relatively low overall profile that does not interfere with surrounding cardiac structures.
3Strength
If conventional collapsible heart valves use excessive radial force for securement, then anchoring is improved, but device complexity increases to control force application
Solution Approach 1:
The nested cells are configured to pivot automatically about connecting struts during deployment, creating a self-regulating clamping mechanism. The geometry of the nested cells and connecting struts inherently limits the pivoting range and force applied, providing secure anchoring without requiring complex external control mechanisms to regulate force application.
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
This solution provides a robust and stable anchoring mechanism that reduces relative motion between the prosthetic and native valves, minimizing the risk of displacement and tissue damage, while maintaining a low profile to avoid interference with surrounding structures.
Implementation Method 1
utilizing shape-memory alloys and connecting struts to securely anchor the valve by rotating and reverting to a shape-set configuration
Data Source
Figure 1
Figure 2~3B
Figure 3C~3D
AI summary
A collapsible and expandable stent (320) extends in an axial direction from a proximal end to a distal end. The stent may include a plurality of first cells (324), each first cell having an open space defined by a first plurality of struts (322). The stent may further include a second cell (330) nested in the open space of one of the first cells, the second cell being defined by a second plurality of struts (330a-d). The stent may additionally include first and second connecting struts (332, 334) connecting the second cell to the one first cell. The second cell may be configured to pivot about the first and second connecting struts with respect to the one first cell. The pivoting may create a clearance space between the second cell and an outer perimeter of the stent in which portions of a native valve structure may be clamped.