Heart Valve Delivery Capsule Retraction for Precise Centering
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Solution Overview
Problem
Existing delivery devices for percutaneous transcatheter implantation of stented prosthetic heart valves suffer from inaccurate and unpredictable steering due to a long lever arm, leading to potential complications such as paravalvular leakage and the need for a permanent pacemaker.
Innovation Solution
A delivery device design featuring a capsule assembly that transitions between expanded and collapsed configurations, with the capsule retracting into an outer stability shaft to minimize steering inaccuracies, allowing for precise centering of the stented prosthetic heart valve at the treatment site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard delivery device with a long lever arm is used, then the capsule can be fully retracted to release the stented prosthetic heart valve, but steering accuracy deteriorates leading to unpredictable positioning
Solution Approach 1:
The capsule is designed to transition between expanded and collapsed configurations dynamically. During delivery, the capsule remains in an expanded configuration to maintain a short lever arm for accurate steering. Upon deployment, the capsule collapses to allow full retraction and valve release, thus resolving the contradiction between steering accuracy and release capability
Solution Approach 2:
The system changes the geometric parameter of the capsule (its configuration state) to optimize performance at different stages. In the expanded configuration, the capsule provides a short lever arm for precise steering control. In the collapsed configuration, it allows sufficient retraction distance for complete valve deployment, thereby addressing both steering accuracy and release requirements
2Measurement precision
If the capsule is kept in an expanded configuration during delivery, then steering accuracy is improved, but the device complexity increases due to the need for configuration transition mechanisms
Solution Approach 1:
The capsule configuration transition is achieved through self-service mechanisms where the capsule's own structural properties enable the transition. The capsule naturally collapses upon valve deployment without requiring complex external actuation systems, thus improving steering accuracy while minimizing the addition of complex mechanical components
Solution Approach 2:
The collapsed capsule is designed to nest within the delivery device structure, specifically within the outer stability shaft. This nesting arrangement allows the capsule to transition from an expanded configuration during delivery to a collapsed state for deployment, achieving accurate steering while keeping the overall device structure compact and manageable
3Productivity
If the capsule retracts fully to release the valve, then valve deployment is complete, but steering inaccuracies accumulate over the longer lever arm distance
Solution Approach 1:
The capsule is positioned and centered on the valve annulus before the valve deployment action occurs. By establishing accurate positioning in the expanded configuration while the lever arm is still short, the system performs the critical centering action preliminarily, ensuring accurate valve placement even as the capsule subsequently retracts for complete deployment
Data Source
AI summary
A delivery device for percutaneously delivering a stented prosthetic heart valve includes a capsule assembly, a handle, and an outer stability shaft. The capsule assembly includes a capsule and a proximal shaft coupled to the capsule. The capsule includes an expanded configuration wherein the capsule has a first outer diameter, and a collapsed configuration wherein the capsule has a second outer diameter smaller than the first outer diameter. The outer stability shaft defines a lumen and is coupled to the handle and configured to receive the proximal shaft within the lumen of the outer stability shaft. The outer stability shaft has an inner diameter, wherein the first outer diameter of the capsule is greater than the inner diameter of the outer stability shaft and the second outer diameter of the capsule is smaller than the inner diameter of the outer stability shaft.