Alternating Cuff-Stent Stitching for Prosthetic Valve Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inaccurate deployment and anchoring of prosthetic heart valves can lead to perivalvular leakage, reducing cardiac efficiency and straining the heart muscle, particularly in aortic valves with calcified tissues, and anatomical variations complicate wear and durability.
Innovation Solution
A stitching technique is applied to the cuff of the prosthetic heart valve, alternating between stitches sewn to the cuff only and stitches sewn to both the cuff and stent, to secure the cuff to the stent and minimize bending, ensuring a larger effective orifice area and better sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cuff is coupled to the stent using conventional stitching methods, then the cuff is secured to the stent, but perivalvular leakage occurs due to inaccurate deployment and anchoring
Solution Approach 1:
The cuff is pre-formed with an integrated stitching pattern attached to the stent before valve assembly. This preliminary attachment ensures accurate positioning and prevents perivalvular leakage by eliminating the need for post-assembly stitching adjustments that could compromise sealing accuracy.
Solution Approach 2:
The stitching pattern is designed with specific geometric parameters including alternating stitch lengths (first stitch longer than second stitch) and optimized spacing to accommodate anatomical variations in native valve annuli. This parameter optimization ensures reliable sealing across different patient anatomies while maintaining deployment accuracy.
2Adaptability or versatility
If the cuff is made flexible to accommodate anatomical variations, then adaptability improves, but structural stability deteriorates
Solution Approach 1:
The cuff is divided into multiple segments or zones with different flexibility characteristics. The stitching pattern creates localized rigid zones for stability while maintaining flexible zones for anatomical adaptation. This segmentation allows the cuff to conform to irregular annuli while maintaining structural integrity during deployment and operation.
Solution Approach 2:
The cuff incorporates composite construction with varying material properties along its length. Certain regions use more flexible materials to accommodate anatomical variations, while other regions use stiffer materials to maintain structural stability. The integrated stitching pattern reinforces these composite zones to prevent over-expansion or deformation.
3Ease of manufacture
If the stitching pattern is simplified for easier manufacture, then manufacturing complexity reduces, but sealing effectiveness deteriorates
Solution Approach 1:
The complex stitching pattern is pre-formed and integrated into the cuff during manufacturing rather than being applied separately during assembly. This preliminary integration maintains the sophisticated alternating stitch pattern needed for effective sealing while simplifying the overall manufacturing process by eliminating multi-step stitching operations.
Solution Approach 2:
The stitching pattern is merged with the cuff structure as an integrated component rather than a separate attachment element. This combining of the cuff and stitching into a single manufactured unit preserves the complex geometric pattern necessary for sealing effectiveness while reducing manufacturing steps and improving consistency.
Data Source
AI summary
A prosthetic heart valve includes a collapsible and expandable stent having a proximal end, a distal end, an annulus section adjacent the proximal end and an aortic section adjacent the distal end, the stent including a plurality of struts. A cuff may be coupled to the stent so that a flat, bottom edge of the cuff lies adjacent the proximal end of the stent. A pattern of stitches may be circumferentially disposed around the flat bottom edge of the cuff, the pattern of stitches alternating between stitches sewn to the cuff only and stitches sewn to both the cuff and the stent.