Expandable Microsphere Sealing for Paravalvular Leak Prevention
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Solution Overview
Problem
Conventional collapsible prosthetic heart valves suffer from paravalvular leaks due to inadequate sealing and anchoring, particularly in cases with uneven calcification or unresected native valve leaflets, leading to adverse clinical outcomes such as blood regurgitation and reduced cardiac performance.
Innovation Solution
A prosthetic heart valve design featuring a stent with an external cuff containing expandable microspheres that expand to fill gaps between the valve and the native valve annulus, providing superior sealing without excessive radial force, using a cuff with a porous outer portion and a pocket for the microspheres that are activated by blood or bodily fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional prosthetic valve with a fixed cuff is used, then the device structure is simple, but gaps form between the cuff and implant site causing paravalvular leakage
Solution Approach 1:
The cuff is designed with expandable microspheres that can dynamically change volume in response to fluid pressure, allowing the sealing surface to adapt and conform to the implantation site geometry, thereby eliminating gaps and preventing paravalvular leakage
Solution Approach 2:
The microspheres within the cuff change their physical state from collapsed to expanded when exposed to blood or bodily fluids, altering the cuff's outer diameter and shape to achieve optimal sealing contact with the annulus without requiring complex mechanical adjustment mechanisms
2Reliability
If excessive radial force is applied to ensure sealing, then paravalvular leaks are reduced, but the risk of annular damage and malpositioning increases
Solution Approach 1:
The radial force application is dynamic rather than static - the microspheres gradually expand in response to fluid pressure, allowing the cuff to progressively conform to the annulus and achieve sealing through controlled expansion rather than sudden high-force application, thereby reducing risk of annular damage
Solution Approach 2:
The sealing force is distributed locally where needed - the expandable microspheres allow different regions of the cuff to expand independently to match the local geometry of the implantation site, providing customized sealing pressure at each location rather than uniform radial force, which prevents over-compression and tissue damage
3Adaptability or versatility
If the valve is designed to accommodate uneven calcification and unresected leaflets, then adaptability to different patient anatomies is improved, but manufacturing precision becomes more difficult
Solution Approach 1:
The cuff geometry is made dynamic through the expandable microsphere mechanism, allowing a single manufactured cuff design to adapt to various anatomical configurations including uneven calcification and unresected leaflets, eliminating the need for multiple precisely manufactured cuff variants for different patient anatomies
Solution Approach 2:
The outer diameter and shape parameters of the cuff are designed to be variable through microsphere expansion, allowing the same manufactured cuff to achieve different final geometries based on the implantation site characteristics, thereby accommodating anatomical variations without requiring complex manufacturing processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design significantly reduces paravalvular leaks by ensuring a tight seal between the prosthetic valve and the native valve annulus, enhancing cardiac performance and reducing clinical complications associated with improper fitment and calcification.
Implementation Method 1
The microspheres are made from a hydrophilic material and are configured to expand upon contact with blood or other bodily fluids
Implementation Method 2
The outer portion of the cuff is porous and the microspheres are positioned outside of the stent
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A prosthetic heart valve (100', 100") includes a valve assembly mounted to an expandable stent (102). The prosthetic heart valve includes a cuff (300) coupled to the stent. The cuff includes a pocket (306) formed between an outer side (302) and an inner side (304) of the cuff. The pocket includes a plurality of biocompatible and irreversibly expandable microspheres (310). After implantation of the prosthetic heart valve into a patient, any gaps existing between the cuff and the native heart valve are exposed to bodily fluid, such as blood. The blood enters the pocket of the cuff through pores (320) in the outer side of the cuff. The blood interacts with the microspheres, causing irreversible expansion of the microspheres. The microspheres expand to fill any gaps between the prosthetic heart valve and the native heart tissue, sealing the gaps and preventing leakage through the gaps.