String-Rod Mechanism for Transcatheter Valve Deployment

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Solution Overview

Problem

Existing medical device deployment methods, such as those for prosthetic mitral valves, often risk damaging the device or dislodging it during the retraction of a nose cone, especially when trying to maintain a distal portion in a radially constrained configuration after radial expansion of chord-recruiting arms.

Innovation Solution

A string-rod constraining mechanism is used to maintain the distal portion of the medical device in a radially constrained configuration, where strings extend from the device to a rod within the delivery catheter, allowing the proximal portion to expand without the need for a nose cone, reducing the risk of damage or dislodgement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a nose cone is used to maintain the distal portion in a radially constrained configuration, then the device can be deployed with selective expansion, but the device may be damaged or dislodged during nose cone retraction

Engineering Contradiction:

Improveselective radial expansion capabilityVSAvoiddevice integrity during deployment

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent removes the nose cone component from the delivery system entirely, replacing it with a string-rod constraining mechanism. This extraction eliminates the harmful retraction action that caused device damage while preserving the ability to maintain radial constraint on the distal portion during deployment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces strings as an intermediary mechanism between the rod and the distal portion of the device. These strings provide the constraining force needed to maintain radial constraint without requiring direct contact between the rod and device, thereby eliminating the dislodgement risk associated with nose cone retraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the distal portion is maintained in radially constrained configuration using a string-rod mechanism, then the risk of device damage is reduced, but the device complexity increases

Engineering Contradiction:

Improvedevice integrity during deploymentVSAvoiddelivery system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses flexible strings instead of rigid structural components to maintain radial constraint. These thin, flexible elements provide the necessary constraining force while being minimally invasive and easy to retract, thereby reducing overall system complexity compared to traditional nose cone designs.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20230380968A1Transcatheteral deployment of a medical device without use of a nose cone

Publication Date: 2023.11.30 SHEBA IMPACT LTD

AI summary

Apparatus and methods are described including a medical device (22, 90), and a delivery catheter (24) that is configured deliver the medical device (22, 90) to a portion of subjects body. An overtube (40) is configured to maintain a proximal portion of the medical device (22, 90) in a radially-constrained configuration, during delivery of the medical device (22, 90) to the portion of the subjects body. A string-rod constraining mechanism (41) includes a rod (44) disposed at least partially within the overtube (40), and at least one string (42). The string-rod mechanism (41) maintains a distal portion of the medical device (22, 90) in a radially-constrained configuration, when the overtube (40) is not covering the distal portion of the medical device (22, 90), by the at least one string (42) extending from the distal portion of the medical device to the rod (44). Other applications are also described.