Stent Cell Bridge for Cuff Attachment in Prosthetic Heart Valves
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Solution Overview
Problem
Prosthetic heart valves often experience paravalvular leakage due to inaccurate placement and anatomical variations, leading to reduced cardiac efficiency and increased risk of infection during removal, necessitating methods to minimize leakage and improve anchoring within the patient's anatomy.
Innovation Solution
A collapsible prosthetic heart valve design featuring a stent with a cuff that extends across intermediate portions of cells in the second circumferential row, allowing for improved sealing and reduced obstruction of coronary arteries, while maintaining coronary perfusion by strategically positioning the cuff to cover potential gaps and adapt to calcified tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a prosthetic heart valve is placed to seal against the native valve annulus, then paravalvular leakage is reduced, but coronary artery ostia may be obstructed
Solution Approach 1:
The cuff is designed with varying properties along its length: the first portion (proximal end) is configured to seal against the native valve annulus to prevent paravalvular leakage, while the second portion (distal end) is configured to clear or not obstruct the coronary artery ostia. This local differentiation of function allows the single cuff structure to simultaneously achieve both sealing effectiveness and coronary artery patency.
2Reliability
If the cuff extends further distally to seal gaps, then paravalvular leakage is minimized, but coronary perfusion is obstructed
Solution Approach 1:
The cuff's distal portion is specifically designed with different geometric or structural characteristics compared to the proximal portion. The distal end may have a reduced profile, different radial force characteristics, or specific cell structure that allows it to clear the coronary artery ostia while the proximal end maintains strong sealing capability against the annulus.
3Strength
If the prosthetic valve is made non-collapsible for structural stability, then anchoring strength is improved, but invasiveness of delivery procedure increases
Solution Approach 1:
The stent is designed as a dynamic structure that transitions from a compressed state during delivery to an expanded state after implantation. The self-expanding mechanism allows the stent to achieve its full structural strength and anchoring capability only after deployment, during which it can be delivered through a minimally invasive catheter-based approach. The stent's material properties (such as shape memory alloy) enable it to automatically expand and conform to the annulus geometry, providing strong anchoring without requiring open-heart surgery.
Data Source
AI summary
A prosthetic heart valve includes a collapsible stent extending from an inflow end to an outflow end, and a cuff having an inflow end an outflow end. The stent includes first and second circumferential rows of cells defined by first and second pluralities of struts, respectively. The second circumferential row is positioned closer to the outflow end of the stent than the first circumferential row. At least one cell in the second circumferential row includes by a first strut opposed to a fourth strut and a second strut opposed to a third strut. A bridging feature in at least one cell in the second circumferential row includes first and second supplemental struts extending across an intermediate portion of the cell. The outflow end of the cuff is coupled to the stent along the bridging feature.