Stent-Valve Sheath Release Geometry for Stable Valve Placement
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Solution Overview
Problem
Existing delivery systems for prosthetic heart valves face issues with embolization due to rapid and asymmetric expansion during deployment, particularly in anatomies with tight curves, leading to undesired deployment locations and increased risk of valve migration.
Innovation Solution
A delivery system with strategically angled proximal and distal sheaths that allow controlled, incremental release of the stent-valve portions, using radiopaque markers for alignment, to ensure symmetrical and controlled expansion, reducing the risk of embolization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional delivery system is used for prosthetic heart valve implantation, then the valve can be delivered through arterial passageways, but rapid and asymmetric expansion occurs during deployment leading to embolization and undesired deployment locations
Solution Approach 1:
The delivery system is divided into two separate sheaths: a distal sheath that releases the lower portion of the stent-valve and a proximal sheath that releases the upper portion. This segmentation allows independent control of each release action, enabling the operator to first deploy the lower portion for anchoring, then subsequently deploy the upper portion to complete the valve implantation, thereby preventing asymmetric expansion and embolization
Solution Approach 2:
The distal sheath is designed with an angled proximal edge that facilitates preliminary release of the lower portion of the stent-valve before the upper portion is released. This preliminary action allows the lower portion to expand first and provide anchoring stability, establishing a stable foundation before the upper portion is released to complete the deployment
2Ease of operation
If the distal sheath has a straight proximal edge, then the structure is simple, but release of the stent-valve lower portion is asymmetric particularly in anatomies with tight curves
Solution Approach 1:
The distal sheath incorporates an angled proximal edge rather than a straight edge, creating an asymmetric geometry that is specifically designed to interact with the curved anatomy of the aorta. This asymmetric shape allows the sheath to conform to and release the stent-valve lower portion symmetrically even when navigating tight anatomical curves, as the angle compensates for the curvature of the delivery path
Data Source
AI summary
A delivery system for delivering a stent-valve may include an inner shaft including a distal tip, a stent-valve crimped onto the inner shaft, a distal sheath disposed over at least a lower portion of the stent-valve, and a proximal sheath disposed over at least an upper portion of the stent-valve. The distal sheath has a proximal free end with an angled proximal edge defining a short side and a long side of the distal sheath. The proximal sheath is actuatable independently from the distal sheath, and moveable proximally to release the upper portion of the stent-valve. The distal sheath is moveable distally to release the lower portion of the stent-valve. The angled proximal edge releases a first side of the lower portion of the stent-valve before an opposite second side.