Heart Valve Leaflet Fixing via Nested Rods to Reduce Sheath Diameter
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Solution Overview
Problem
Existing artificial heart valve devices are too large and have a thick delivery sheath, which increases the risk of damage to blood vessels during surgical procedures and limits their applicability to patients with thin blood vessels.
Innovation Solution
The design includes a tubular stent body with fixing structures such as fixing rods and main bodies with through holes, where the leaflet is fixed using connecting portions that pass through these holes, reducing the maximum outer diameter of the valve and allowing it to be delivered through a thinner sheath, and incorporating a skirt structure to prevent perivalvular leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the leaflet is fixed using traditional sutured portions extending out of the framework, then the leaflet can be securely attached, but the valve device becomes thicker requiring a larger delivery sheath
Solution Approach 1:
The connecting portion is nested within the hollow of the framework rather than extending outward. The fixing rod passes through the connecting portion and is received within the hollow, creating a compact nested structure that reduces the overall outer diameter while maintaining secure attachment of the leaflet to the framework
Solution Approach 2:
The attachment structure transitions from a radial extension (sutured portion extending outward) to an axial arrangement (fixing rod passing through the hollow from one end to the other). This dimensional reorganization allows the same attachment function to be achieved with a smaller radial profile, reducing the required delivery sheath diameter
2Reliability
If a thicker delivery sheath is used to deliver the valve device, then the valve can be delivered safely, but the risk of damage to blood vessels increases
Solution Approach 1:
The nested configuration of the connecting portion within the framework hollow, with the fixing rod received inside, creates a compact valve device that fits within a thinner delivery sheath. This reduces the outer diameter of the delivery system, thereby reducing the risk of damage to blood vessels during the delivery procedure
3Object-affected harmful factors
If the valve device is made smaller to reduce sheath size, then blood vessel damage risk is reduced, but the mechanical strength and fatigue life may be compromised
Solution Approach 1:
The framework is segmented into multiple struts with hollows, and the leaflet is segmented into valve lobules with connecting portions. This segmentation allows for a distributed attachment system where multiple fixing rods secure the leaflet at different locations, maintaining mechanical strength and fatigue resistance while keeping each individual component compact for reduced overall device size
Data Source
Figure 1~2b
Figure 3a~4
Figure 5~6
AI summary
A heart valve prosthesis device (100) comprises a tubular stent body (11) having an inflow end (10A) and an outflow end (10B); a leaflet (12) disposed in the lumen of the stent body (11); and fixing structures (13) connected with the stent body (11) and configured to fix the leaflet(12) on the stent body (11). The leaflet (12) comprises at least two halves (121), and a connecting portion(s) (122) connecting two adjacent halves. The fixing structure (13) comprises a closed hollow portion (115) located on the stent body (11), and a fixing rod (132) disposed in the hollow portion (115); one end of the fixing rod (132) is connected to the hollow portion (115), and the other end is a free end; the connecting portion (122) is hung on the fixing rod (132) from the free end so as to fix the leaflet (12) on the stent body (11). The fixing structure improves the mechanical strength and fatigue durability of the leaflet, reduces the maximum outer diameter of the heart valve prosthesis after compression, reduces the size of the delivery sheath required for the heart valve prosthesis, and reduces the risk of damage of the sheath to blood vessels during surgery.