Transcatheter Heart Valve Leaflet Inversion and Segmentation
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Solution Overview
Problem
The challenge in the medical field of structural heart is the difficulty in placing a transcatheter heart valve inside a previously placed cardiac valve due to obstruction by existing valve leaflets, which can block coronary blood flow and catheter access, posing significant risks to patients.
Innovation Solution
A percutaneous valve cutter is used to make longitudinal cuts in the original leaflets of the existing cardiac valve, allowing for the placement of a replacement valve with a self-expanding nitinol frame that opens up access to the coronary arteries, and a specifically designed replacement valve is deployed using a guidewire and delivery catheter system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transcatheter valve is placed inside a previously placed cardiac valve, then valve replacement is achieved, but the existing valve leaflets obstruct coronary blood flow and catheter access
Solution Approach 1:
The existing valve leaflets are divided into segments by making radial incisions from the valve annulus toward the coronary ostia. This segmentation creates separate access pathways through the leaflets, allowing coronary catheters to reach the coronary arteries while the valve replacement procedure proceeds. The incisions effectively segment the obstructive leaflet structure into manageable sections that no longer block coronary flow.
Solution Approach 2:
A specialized coronary access device is introduced as an intermediary tool to navigate through the incised leaflet segments. This device serves as a mediator that creates a safe passage through the valve leaflets to reach the coronary arteries, allowing coronary access without directly manipulating or risking damage to the coronary ostia themselves during the valve replacement procedure.
2Stability of the object's composition
If existing valve leaflets are left intact, then valve structure is preserved, but catheter access to coronary arteries is blocked
Solution Approach 1:
The valve leaflets are radially incised to create segmented access pathways. These incisions divide the continuous leaflet structure into sections, creating channels that allow catheters to pass through the valve mechanism and reach the coronary arteries. The segmentation maintains the overall valve structure while providing necessary access routes.
Solution Approach 2:
The problem of catheter access is solved by transitioning from a planar approach to a three-dimensional approach. Instead of trying to access coronaries from the standard catheter insertion path, the incisions create new spatial dimensions and pathways through the leaflet thickness and radial orientation, allowing catheters to navigate through the valve structure in multiple directions to reach the coronary ostia.
3Ease of operation
If radial incisions are made in valve leaflets, then coronary access is opened, but valve leaflet structure is altered
Solution Approach 1:
The radial incisions in the valve leaflets are performed as a preliminary action before the valve replacement procedure. By pre-opening access pathways through the leaflets, subsequent catheter manipulation and coronary access become significantly easier and safer. This preliminary modification of leaflet structure eliminates the need for complex intra-procedural leaflet manipulation during valve replacement.
Solution Approach 2:
The leaflet structure is transformed from a static, closed configuration to a dynamic, partially open state through the radial incisions. The incised leaflets can now move and separate more freely, creating variable access pathways that can be opened or closed as needed during the procedure. This dynamic modification allows flexible coronary access while maintaining valve function.
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
This method effectively resolves the obstruction issue by creating an access window for blood flow and catheter access, enabling safe and efficient replacement of the transcatheter valve, reducing the risk of complications during the procedure.
Implementation Method 1
The basic structure of the replacement valve is a self-expanding nitinol frame. The replacement valve is compressed on a delivery catheter and expanded with the retraction of an outer sheath.
Data Source
AI summary
A procedure for placing a cardiac valve includes cutting leaflets of another cardiac valve, expanding the cardiac valve, applying a downward pushing force to the expanded cardiac valve, and inverting the cut leaflets of the other cardiac valve toward a ventricle. The cardiac valve includes a self-expanding frame, vertical posts coupled to the self-expanding frame, and valve leaflets coupled to the self-expanding frame or to the vertical posts. Each of the vertical posts includes a connection to a corresponding control wire.