Tissue Ligation Device with Adaptive Suture Loop

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Solution Overview

Problem

Current methods for closing the left atrial appendage, such as suturing or stapling, are invasive, carry risks, and may lead to leaks due to tissue remodeling, necessitating the development of minimally invasive or less invasive techniques for effective thrombus prevention in atrial fibrillation patients.

Innovation Solution

The development of tissue closure devices featuring an elongate body with a snare and tightening element, including a suture or snare loop, and a force generator like compression springs or expandable polymers, which can maintain closure force even as tissue size changes, using one-way mechanisms to ensure secure ligation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If open-heart surgery with suturing is used to close the left atrial appendage, then effective thrombus prevention is achieved, but the procedure carries high risk and is only available to patients undergoing open-heart surgery

Engineering Contradiction:
Improvethrombus prevention effectivenessVSAvoidsurgical risk and invasiveness
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical suturing system (needles, threads, sutures) with a controlled delivery system that uses radial expansion forces. The collapsible structure is delivered in a compressed state through a catheter and expanded at the target site, eliminating the need for open-heart surgery and general anesthesia while achieving effective appendage closure

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a catheter-based delivery system as an intermediary between the operator and the closure device. The catheter allows minimally invasive access to the left atrial appendage through vascular routes, avoiding the need for chest opening and direct surgical manipulation of the appendage

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If suturing is performed to close the left atrial appendage, then blood flow into the appendage is cut-off, but tissue remodeling and shrinking can cause leaks over time

Engineering Contradiction:
Improveclosure effectivenessVSAvoidlong-term closure durability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a dynamic closure system where the collapsible structure can adapt to tissue remodeling. The structure includes features that allow it to maintain sealing contact with the appendage wall even as the tissue shrinks or changes shape over time, preventing leaks that would occur with rigid sutures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary compression and sealing forces during the closure process to ensure immediate and effective sealing of the appendage ostium. The controlled expansion of the collapsible structure creates initial high-contact-pressure sealing that prevents thrombus formation from the outset

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of operation

If stapling or occlusion devices are used to close the left atrial appendage, then minimally invasive procedures are enabled, but stapling may cause tissue rupture and occlusion devices may not effectively prevent all blood flow

Engineering Contradiction:
Improveminimally invasive capabilityVSAvoidclosure effectiveness and tissue integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the physical parameters of the closure device from rigid (staples, rigid occluders) to collapsible and compliant. The structure can be compressed to a small profile for delivery, then expanded to achieve closure with controlled radial forces that adapt to the soft tissue, avoiding both stapling-induced rupture and incomplete occlusion

Inventive Principle:
Principle #35Parameter changes

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

These devices enable secure, minimally invasive closure of the left atrial appendage, reducing the risk of leaks and thrombus formation, while being adaptable to tissue remodeling, thus providing a safer and more effective alternative to traditional methods.

Implementation Method 1

The force generator may comprise a compression spring

Methodology Applied
Scientific EffectCompression spring: Spring

Implementation Method 2

the force generator may comprise an expandable polymer

Methodology Applied
Scientific EffectExpandable polymer: Shape Memory Polymer

Implementation Method 3

the force generator may comprise a shape memory alloy

Methodology Applied
Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 4

the force generator may comprise a bladder. In some embodiments, the bladder may be at least partially filled with a liquid

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP3273870B1Tissue ligation devices
Publication Date: 2023.12.13 ATRICURE INC
  • EP3273870B1 patent drawingFigure 1
  • EP3273870B1 patent drawingFigure 2A
  • EP3273870B1 patent drawingFigure 2B

AI summary

Described herein are tissue closure devices and methods for ligating a target tissue, such as the left atrial appendage. The tissue closure device may have an elongate body, a snare at least partially housed within the elongate body, a suture at least partially housed within the elongate body, and a tightening element coupled to the suture. The suture may have a suture loop, and the tightening element may be configured to decrease the size of the suture loop when the area of a tissue within the suture loop decreases.