Biased Cell Cardiac Valve Structure for 15F Delivery
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Solution Overview
Problem
Existing transluminal cardiac valves, particularly xenograft valves, face challenges such as large catheter sizes, thrombogenicity, rigidity, and potential for prion transmission, limiting their use in individuals with small femoral arteries and requiring alternative access methods, and they often limit coronary access.
Innovation Solution
A low-profile, self-expanding cardiac valve made of a single piece superelastic metal frame with polymer-covered leaflets, configured to flex in- and out-of-plane, allowing percutaneous delivery through a 15 F catheter, and incorporating biased cells to modulate leaflet deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional transluminal cardiac valves are used, then valve function is provided, but large catheter sizes are required which limits use in individuals with small femoral arteries
Solution Approach 1:
The valve is divided into multiple biased cell units that can be collapsed into a compact configuration for delivery through small catheters, then expanded to functional size at the implantation site. This segmentation allows the valve to pass through 15F catheters while maintaining full functional dimensions when deployed.
Solution Approach 2:
The valve structure employs nested configurations where the valve frame and leaflets are collapsed within the catheter lumen during delivery, similar to nested dolls. The biased cells are compressed into a low-profile state that fits within small catheter bore, then expand to full size upon deployment.
2Reliability
If xenograft valves are used, then valve replacement is achieved, but thrombogenicity and risk of prion transmission occur
Solution Approach 1:
The invention changes the material parameter from biological tissue (xenograft) to synthetic materials (polymer and metal). The valve leaflets are made from thromboresistant polymers and the frame from superelastic metal, fundamentally altering the material composition to eliminate biological hazards while maintaining valve function.
Solution Approach 2:
The valve employs composite construction combining superelastic metal frame (nitinol or cobalt-chromium alloy) with polymer leaflet material. This composite structure provides mechanical strength from the metal while the polymer provides thromboresistance and biocompatibility, eliminating the thrombogenicity associated with xenograft tissue.
3Strength
If conventional cardiac valve designs are used, then valve function is provided, but rigidity limits flexibility and coronary access
Solution Approach 1:
The valve incorporates flexible polymer leaflet material that can bend and flex to accommodate coronary artery anatomy. The leaflets are thin films that provide adequate strength while allowing the valve to conform to curved vascular paths and provide access to coronary ostia.
Solution Approach 2:
The valve employs dynamic structures with biased cells that can flex and adapt during deployment and operation. The superelastic metal frame and flexible polymer leaflets allow the valve to dynamically adjust to vascular anatomy, providing both structural integrity and flexibility for coronary access.
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 solution provides a cardiac valve with enhanced fatigue resistance, chronic durability, and biocompatibility, enabling safe and effective percutaneous implantation without large catheters, reducing thrombogenic risk and improving coronary access.
Implementation Method 1
a low-profile, self-expanding cardiac valve made of a single piece superelastic metal frame
Implementation Method 2
Each biased cell is configured to assume a substantially quadrilateral shape as a directional strain is applied to the biased cell
Data Source
AI summary
A method of making a biased cardiac valve including a cell configured to flex out-of-plane upon application of a lateral or circumferential force applied to the biased cell, the biased cell having an elongate member projecting axially from an apex of the biased cell that flexes out-of-plane concomitantly with out-of-plane flexion of the biased cell. A monolithic hypotube is formed into a lattice structure having a plurality of biased cells and elongate members and is configured into a cardiac valve having a main body portion, a valve leaflet portion, and a plurality of elongate biasing arm members. A polymer coating or covering is disposed on the valve leaflet portion and the elongate biasing arm members and subtends space between adjacent pairs of elongate biasing arm members to form valve leaflet cusps that are biased toward a central axis of the cardiac valve by the elongate biasing arm members.