Bioprosthetic Tissue Crimping via Patterned Substrate
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Solution Overview
Problem
Existing bioprosthetic heart valve designs face challenges in controlled tissue folding during crimping, leading to potential tissue damage and increased packing density due to uncontrolled folding, which affects the crimp profile and deployment efficiency.
Innovation Solution
A method involving a patterned substrate with raised regions and areas of relief is used to deform bioprosthetic tissue, reducing thickness and density in specific areas to facilitate controlled folding and minimize tissue damage, by compressing the tissue against the substrate and treating it with a fixative to create a patterned leaflet structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If bioprosthetic tissue is crimped down to reduced size for transcatheter delivery, then the valve can be delivered through vasculature, but the tissue folds in an uncontrolled manner causing damage and increased packing density
Solution Approach 1:
The tissue is pre-patterned with crease lines and folded configurations before crimping, so that during compression the tissue follows predetermined fold paths rather than folding randomly. This preliminary structuring prevents uncontrolled folding and tissue pinching by the frame diamonds during the crimping process.
Solution Approach 2:
The tissue is divided into multiple folded sections or lobes that can collapse independently into the available space within the crimped stent formation. This segmentation allows each segment to fold along controlled crease lines, distributing the compression stress and preventing any single area from being pinched or damaged.
2Volume of moving object
If tissue is compressed to reduce thickness, then crimp profile is improved, but tissue density increases causing uncontrolled folding
Solution Approach 1:
Crease lines are pre-formed in the tissue before compression, creating predetermined pathways for folding. When the tissue is compressed to reduce thickness, these pre-existing crease lines guide the folding process, ensuring that the tissue folds in a controlled manner rather than creating random folds due to increased density.
3Volume of moving object
If tissue is folded to fit within crimped stent formation, then delivery profile is reduced, but packing density increases causing tissue damage
Solution Approach 1:
The tissue is segmented into multiple folded sections that can be distributed within the crimped stent formation. This segmentation allows the tissue to occupy the available space more efficiently without creating excessive local packing density, as each segment folds independently along controlled crease lines rather than compressing into a single dense region.
Solution Approach 2:
Different regions of the tissue are given different properties through selective crease line placement and folding patterns. Areas with pre-formed creases fold more easily and occupy less space, while areas without creases maintain their structural integrity. This local differentiation allows the tissue to achieve compact packaging without creating damaging density concentrations in any single area.
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 method enables bioprosthetic tissue to fold more predictably and reduces tissue thickness, enhancing the crimp profile and deployment efficiency of transcatheter valve designs while minimizing tissue damage, thereby improving the functionality and durability of prosthetic heart valves.
Implementation Method 1
compressing the tissue against the engagement face to deform the tissue to a deformed state corresponding with the pattern
Implementation Method 2
treating the tissue with a fixative
Data Source
AI summary
Conditioned bioprosthetic tissues for forming prosthetic valves including a sheet of bioprosthetic tissue having a first major surface and a second major surface. The first major surface has a pattern including at least one depressed region and areas of relief adjacent to the at least one depressed region. The at least one depressed region has a first tissue density that is greater than a second tissue density of the areas of relief.