Occlusion Device Framework with Segmented Struts for LAA Seal
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Solution Overview
Problem
Existing occlusion devices for the left atrial appendage lack sufficient circumferential and radial strength, leading to distortion and potential failure to prevent emboli, and suffer from foreshortening issues that affect deployment accuracy.
Innovation Solution
A framework design with a proximal, middle, and distal portion, featuring a biocompatible covering and strut pairs that maintain stability and flexibility, allowing for improved circumferential strength without foreshortening, and includes anchors for securement within the LAA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic cage framework is used to support the occlusion device, then the device can maintain its shape and resist distortion forces, but the framework lacks sufficient circumferential and radial strength to resist the distortive forces exerted by the LAA
Solution Approach 1:
The framework is divided into multiple struts arranged in a pattern that provides both structural support and flexibility. The struts are segmented into radial and circumferential components that work together to resist distortion forces while maintaining seal integrity against the LAA wall.
Solution Approach 2:
The framework combines different material properties by using a composite structure of radial struts and circumferential struts. This composite design provides both the necessary strength to resist distortion and the flexibility to conform to the LAA geometry, resolving the contradiction between strength and seal reliability.
2Strength
If the framework is made more rigid to maintain seal integrity, then the device can resist distortion forces, but the device becomes difficult to recapture into the delivery catheter
Solution Approach 1:
The framework employs dynamic struts that can change their mechanical properties based on applied forces. During delivery, the struts remain flexible to allow recapture into the catheter. Once deployed, the struts gain rigidity to maintain seal integrity and resist distortion forces from the LAA.
Solution Approach 2:
The mechanical parameters of the framework (particularly the strut stiffness) change based on the deployment state. The framework transitions from a compliant state during delivery to a rigid state during operation, resolving the contradiction between ease of recapture and structural integrity.
3Ease of operation
If expandable occlusion devices are used to occlude the LAA, then the device can be delivered via catheter, but the devices suffer from foreshortening during expansion that affects deployment accuracy
Solution Approach 1:
The framework is pre-configured with struts arranged in specific geometric patterns that compensate for expansion effects. The radial and circumferential strut arrangement is designed beforehand to maintain accurate positioning and orientation during expansion, preventing foreshortening and ensuring precise deployment at the target site.
Data Source
AI summary
An occlusion device (e.g., for treatment of the left atrial appendage) includes a framework and a biocompatible covering disposed over at least a part of the framework. The framework may include a proximal portion, a middle portion, and a distal portion, wherein: the proximal portion includes a first hub that has a fixed first diameter; the middle portion has a second diameter and includes a plurality of beams extending from the first hub to a distal portion, wherein each of the plurality of beams is connected to an adjacent beam by a first circumferentially extending column of strut pairs; and the distal portion has a third diameter. In one or more embodiments, the framework includes improved circumferential strength and minimizes foreshortening.