Left Atrial Appendage Closure Using Radial Tissue-Pulling Arms
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Solution Overview
Problem
Existing medical devices for closing the left atrial appendage in patients with atrial fibrillation are inadequate in preventing thrombi formation and migration, leading to stroke or heart attack risks.
Innovation Solution
A left atrial appendage closure device with engagement arms and a drive assembly that radially inwardly pull the appendage tissue using a threaded core rod and nut sleeve mechanism to secure the tissue, minimizing exposure to blood flow and reducing thrombosis risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a left atrial appendage closure device is deployed to close off the left atrial appendage, then the risk of thrombi formation is reduced, but the device complexity increases due to the need for engagement arms and drive assembly mechanisms
Solution Approach 1:
The closure device is divided into multiple functional components: a central ring structure, multiple engagement arms (typically 3-6) radially arranged, and a drive assembly. Each engagement arm can independently engage the LAA tissue, allowing the device to handle varying LAA sizes and shapes while maintaining reliability in thrombi prevention.
Solution Approach 2:
The engagement arms are designed to nest within each other or within the central ring structure during delivery, allowing the complex multi-component device to be compressed into a small profile for catheter delivery. After deployment, the arms unfold and radiate outward to engage the LAA, transforming from a compact nested state to an expanded functional state.
2Reliability
If engagement arms are used to pull LAA tissue radially inward, then the closure effectiveness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The engagement arms incorporate shape memory alloy materials (such as nitinol) that undergo phase transitions between martensite and austenite phases. During delivery, the arms are in a flexible martensite state that allows easy deformation and nesting. After deployment in body temperature, they transform to the rigid austenite phase, providing the necessary structural integrity and radial pulling force for effective closure.
3Object-affected harmful factors
If the device is isolated from blood flow to prevent thrombosis, then thrombi formation risk is reduced, but the ease of operation decreases due to complex deployment procedures
Solution Approach 1:
The engagement arms are pre-formed with specific geometries including engagement features (such as hooks, barbs, or clamps) that are designed to automatically engage the LAA tissue upon deployment. The drive assembly is pre-loaded with the engagement arms in a nested configuration, and simple rotational or axial movements of the drive assembly trigger the unfolding and tissue engagement sequence, eliminating the need for complex manual manipulation during the procedure.
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 device effectively closes the left atrial appendage, reducing the risk of thrombi formation and migration, thereby minimizing stroke and heart attack risks by isolating the device from blood flow.
Implementation Method 1
a threaded core rod and nut sleeve mechanism to secure the tissue
Data Source
AI summary
A left atrial appendage closure (LAAC) device is adapted to pull a left atrial appendage (LAA) closed on itself. The LAAC device includes a tissue engagement structure that is adapted to engage tissue within the LAA and pull the tissue inwardly when the tissue engagement structure is driven from an initial actuation level towards a final actuation level. The LAAC device includes a drive assembly that is adapted to drive the tissue engagement structure from the initial actuation level towards the final actuation level.