Prosthetic Valve Leaflet Connectors for Reliable Commissure Coaptation
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Solution Overview
Problem
Ischemic heart disease causes regurgitation of heart valves due to papillary muscle dysfunction and ventricular dilation, leading to incomplete valve coaptation and subsequent blood regurgitation, which increases stroke volume and decreases cardiac output.
Innovation Solution
A prosthetic valve implant with concentric frames, comprising an inner and outer frame, is percutaneously delivered and expanded at the native heart valve, securing tissue between the upstream support portion and flanges, with prosthetic leaflets connected via flexible sheets and connectors to ensure proper coaptation and prevent regurgitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve annulus is dilated, then the valve leaflets cannot fully coapt, but this leads to regurgitation and increased stroke volume
Solution Approach 1:
The prosthetic valve is delivered in a compressed state through a catheter and then expanded at the target site. The frame is preliminarily compressed to fit through the delivery system, then expanded to engage the dilated annulus and force proper coaptation of the leaflets, preventing regurgitation before it occurs during normal valve operation
Solution Approach 2:
The implant changes its physical parameters from a compressed delivery state to an expanded functional state. The frame expands radially to engage the dilated annulus, changing the geometric parameters of the valve structure to restore proper leaflet coaptation and prevent regurgitation in the presence of annular dilation
2Ease of operation
If the prosthetic valve is delivered percutaneously in a compressed state, then it can be minimally invasively implanted, but it requires expansion mechanisms and complex frame structures
Solution Approach 1:
The frame structure is designed to be dynamic rather than static, transitioning from a compressed configuration during delivery to an expanded configuration at the implant site. This dynamic transformation allows the valve to be delivered percutaneously through a catheter and then deployed to its functional shape, engaging the annulus and securing leaflet coaptation
Solution Approach 2:
The prosthetic valve is nested within a delivery catheter in a compressed state, with the frame contained inside the delivery system. The valve is delivered through the catheter in this nested configuration and then expanded at the target site, allowing minimally invasive percutaneous access while maintaining the complex frame structure needed for proper valve function
3Stability of the object's composition
If the outer frame is undersized with respect to the inner frame, then residual stress is present to maintain concentricity, but this creates stress concentrations in the frames
Solution Approach 1:
The outer frame is deliberately designed with a smaller nominal size than the inner frame, creating a parameter mismatch that generates residual compressive stress. This residual stress acts as a pre-load to maintain concentric alignment of the frames during expansion and operation, preventing buckling and maintaining structural stability despite the stress concentrations created by the size difference
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2E
AI summary
A unitary flexible sheet (612) is folded to define (i) a panel (608); (ii) a first tab (606a), having a first-tab outer layer and a first-tab inner layer, and protruding away from the panel; and (iii) a second tab (606b), having a second-tab outer layer and a second-tab inner layer, and protruding away from the panel. A commissural portion of a first prosthetic leaflet (58a), and a commissural portion of a second prosthetic leaflet (58b) are disposed between the first-tab inner layer and the second-tab inner layer. A first stitching (632) is stitched through the inner layer of each tab, and the commissural portion of each leaflet. A second stitching (634) is stitched through the outer and inner layers of each tab, and the commissural portion of each leaflet. The first- tab outer layer and the second-tab outer layer cover the first stitching. Other embodiments are also described.