Left Atrial Appendage Volume Reduction Device
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Solution Overview
Problem
Patients with atrial fibrillation experience thrombi formation in the left atrial appendage due to stagnant blood, leading to stroke risk, and existing medical devices that close off the appendage have negative side-effects such as hypertension and disrupted pressure-volume modulation.
Innovation Solution
A medical device with an elongate shaft and a volume-reducing means that expands to fit within the left atrial appendage, maintaining an open fluid flow path and reducing the appendage's volume to prevent thrombi formation while preserving its functional roles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the left atrial appendage is closed off to prevent thrombi formation, then stroke risk is reduced, but hypertension and disrupted pressure-volume modulation occur
Solution Approach 1:
The patent extracts only the harmful function (thrombi formation) from the left atrial appendage by reducing its volume, while preserving the beneficial functions (pressure-volume modulation, stretch receptor signaling). This is achieved by deploying a collapsible basket device that compresses the appendage tissue without complete occlusion, allowing controlled volume reduction while maintaining physiological functionality.
Solution Approach 2:
The patent applies local quality by creating a gradient of tissue compression within the appendage. The collapsible basket exerts varying degrees of compression on different regions of the appendage wall, with greater compression in areas prone to thrombi formation and lesser compression in regions critical for physiological function. This localized differential compression allows simultaneous thrombi prevention and function preservation.
2Reliability
If the left atrial appendage volume is reduced to minimize stagnant blood, then thrombi formation decreases, but device complexity increases
Solution Approach 1:
The patent segments the appendage treatment function into multiple independent elements of the collapsible basket. The basket comprises numerous individual wires or struts that can independently compress different regions of the appendage. This segmentation allows the device to achieve effective volume reduction through the collective action of many simple elements rather than requiring a single complex mechanism.
Solution Approach 2:
The patent employs a dynamic collapsible basket structure that can transition between expanded and compressed states. The basket is delivered in a low-profile collapsed state through catheter access, then expanded within the appendage to exert compression forces. This dynamic transformation simplifies the delivery mechanism and reduces the need for complex permanent implantation structures.
3Reliability
If a collapsible basket is used to reduce appendage volume, then thrombi formation is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes in the basket material properties to achieve effective compression with tolerable manufacturing tolerances. The basket wires are made from shape memory alloy or elastic materials that can undergo large reversible deformations. This allows the basket to be manufactured with standard tolerances yet still achieve the required compression forces and appendage volume reduction when deployed and inflated.
Data Source
AI summary
A medical device for reducing the volume of a left atrial appendage (LAA) may include an elongate shaft having a distal portion, and a volume-reducing means expandable from a collapsed to an expanded state, the volume-reducing means being releasably attached to the distal portion. The volume-reducing means may include an actuatable frame and an impermeable covering disposed over the frame. The volume-reducing means may be sized to fit within the LAA in the expanded state while maintaining an open fluid flow path from a distal region through the ostium of the LAA. A medical device may include a second volume-reducing means to be placed within and substantially occlude a distalmost region of the LAA. A method may include inserting a volume-reducing means into the LAA, expanding the volume-reducing means, and positioning the volume-reducing means such that an open fluid flow path is maintained through an entire cycle of the heart.