Prosthetic Heart Valve Leaflet Suturing for Tear Resistance
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Solution Overview
Problem
Collapsible prosthetic heart valves face challenges in securing valve leaflets to the stent, leading to potential tearing and failure due to repeated movement, which can have significant consequences for the patient.
Innovation Solution
The leaflets are secured to the stent by suturing the folded end portions of their free edges to commissure points, with optional reinforcement layers and configurations such as U-shaped pleats, spiral rolls, or web overlays to distribute stress and minimize tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If valve leaflets are secured to the stent using conventional attachment methods, then the valve can be assembled, but the repeated movement over millions of cycles causes tearing and failure of the leaflets
Solution Approach 1:
The leaflet attachment is divided into multiple discrete attachment points distributed around the valve circumference rather than a single continuous attachment. Each attachment point secures a specific portion of the leaflet to the stent, creating multiple independent load-bearing points that distribute stress across the entire leaflet structure, preventing localized tearing and extending service life.
2Ease of operation
If the valve is made collapsible for less invasive delivery, then delivery through catheters is enabled, but the repeated expansion and collapse creates stress on the leaflets and stent interface
Solution Approach 1:
The leaflets are pre-attached to the stent in a collapsed configuration before delivery, with attachment points positioned to accommodate the delivery mechanism. This preliminary attachment ensures that when the valve is deployed and expanded, the leaflets are already secured to withstand the mechanical stresses of expansion and subsequent cardiac cyclic loading, maintaining strength throughout the valve's operational life.
3Strength
If multiple attachment points are used to secure leaflets to the stent, then the structural integrity is improved, but the manufacturing complexity increases
Solution Approach 1:
The attachment system is designed to be self-aligning and self-securing through the valve's inherent structural features. The leaflet material and stent geometry work together to automatically position and secure attachment points without requiring complex external tools or multi-step assembly procedures. This self-service approach maintains high structural integrity while simplifying manufacturing by leveraging the valve's own design characteristics.
Data Source
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AI summary
A collapsible prosthetic heart valve (100) includes a collapsible and expandable stent (102) and a collapsible and expandable valve assembly (104). The stent has a proximal end and a distal end. A plurality of commissure points (116) is disposed on the stent. The valve assembly is disposed within the stent and includes a plurality of leaflets (108). Each leaflet has a free edge (505). An end portion (724a, 724b) of the free edge of each leaflet is folded and sutured (730a, 730b) to a corresponding one of the plurality of the commissure points.