Elliptical Heart Valve Prostheses With Varying Strut Widths
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Solution Overview
Problem
Existing heart valve prostheses with circular cross-sections are not well-suited for patients with non-circular or elliptical native heart valves, leading to increased potential for para-valvular leakage (PVL) due to mismatch in shape.
Innovation Solution
A heart valve prosthesis with a frame that has varying strut widths to form an elliptical shape, allowing the prosthesis to expand into a substantially elliptical shape when deployed, which matches the native heart valve anatomy and reduces the risk of PVL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular cross-section heart valve prosthesis is used, then the device is simple to manufacture and deploy, but it causes para-valvular leakage when implanted in non-circular or elliptical native heart valves
Solution Approach 1:
The frame structure employs varying strut widths at different locations to match the elliptical geometry of the native valve annulus. Specifically, the struts have greater width at the major axis of the ellipse and reduced width at the minor axis, creating local structural variations that enable conformal fitting to the non-circular anatomy while maintaining overall structural integrity
Solution Approach 2:
The frame transitions from a symmetric circular design to an asymmetric elliptical design with non-uniform strut distribution. The strut widths are deliberately made asymmetric relative to the circular geometry, with wider struts positioned along the major axis and narrower struts along the minor axis, allowing the prosthesis to match the asymmetric elliptical shape of the native valve
2Shape
If the strut widths are varied to form an elliptical shape, then the fit to native valve anatomy is improved, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing approach varies the geometric parameters of the struts, specifically the width parameter, along the circumferential direction of the frame. By continuously or discretely changing the strut width parameter around the ellipse perimeter, the frame achieves the desired elliptical cross-section shape while maintaining manufacturability through systematic parameter variation
3Reliability
If a circular heart valve prosthesis is deployed in an elliptical native valve, then the deployment process remains simple, but para-valvular leakage occurs due to shape mismatch
Solution Approach 1:
The frame is pre-formed with an elliptical cross-section geometry and non-uniform strut widths before deployment. This preliminary shaping ensures that when the prosthesis is deployed, it naturally conforms to the elliptical native valve annulus without requiring complex real-time adjustments or reconfiguration during the deployment procedure
Data Source
AI summary
A heart valve prosthesis includes a frame and a prosthetic disposed within a lumen of the frame. The frame includes a plurality of struts and crowns and has a radially collapsed state and a radially expanded state. A stiffness of the plurality of struts is varied by varying the width of at least one strut of the plurality of struts such that when the frame is in the radially expanded state, the frame has a substantially elliptical shape.