Dielectric Coated Expandable Frame for Cardiac Ablation
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Solution Overview
Problem
Existing occlusion devices for the left atrial appendage (LAA) lack sufficient circumferential and radial strength to maintain a seal against the LAA wall, leading to potential emboli or blood clots re-entering the bloodstream.
Innovation Solution
A medical device featuring an expandable frame with a dielectric coating on one portion and an uncoated electrode region on another, detachably connected to a catheter system, allowing for precise deployment and energy delivery to ablate tissue and occlude the LAA effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an expandable frame with fabric graft is used to occlude the LAA, then the device can be delivered via catheter system, but the frame lacks sufficient circumferential and radial strength to maintain seal against LAA wall distortive forces
Solution Approach 1:
The expandable frame is divided into multiple interconnected members (struts and rings) that can be delivered in a compressed state within the catheter and then expanded at the target site. This segmentation allows the frame to achieve sufficient strength when deployed while maintaining deliverability in a low-profile configuration.
Solution Approach 2:
The frame transitions from a compressed, flexible state during delivery to an expanded, rigid state at the implantation site. This dynamic transformation allows the same structure to satisfy both deliverability requirements and structural strength requirements for maintaining seal against LAA wall forces.
2Strength
If a metallic cage structure is used to provide sufficient strength, then radial strength is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
A fabric graft is integrated with the metallic frame to create a composite structure. The fabric graft provides the sealing surface and distributes forces across the occlusion site, while the metallic frame provides structural support. This combination achieves sufficient radial strength with a less complex structure than a solid metallic cage.
Solution Approach 2:
The device combines metallic materials (for frame strength) with fabric materials (for sealing and force distribution). This composite construction achieves the required radial strength and sealing performance while reducing the complexity compared to a purely metallic solid cage structure.
3Reliability
If the entire frame is coated with dielectric material for ablation, then electrical insulation is improved, but the ability to deliver ablative energy to tissue is reduced
Solution Approach 1:
The dielectric coating is applied selectively to specific portions of the frame members rather than the entire surface. This allows different regions of the frame to have different electrical properties: coated regions provide insulation where needed, while uncoated regions serve as electrode surfaces for delivering ablative energy to the tissue.
Solution Approach 2:
The frame surface is segmented into coated and uncoated regions, creating distinct functional zones. The coated portions provide electrical insulation for safety and controlled energy delivery, while the uncoated portions function as electrodes for effective tissue ablation.
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 achieves a secure seal within the LAA, preventing emboli and blood clots from re-entering the bloodstream, while also enabling effective tissue ablation to treat atrial fibrillation.
Implementation Method 1
the interconnected members in a first portion of the expandable frame are coated with a dielectric layer
Implementation Method 2
ablation of tissue by electroporation
Data Source
AI summary
A medical device includes an elongate hollow shaft having a shaft proximal end, a shaft distal end, and a lumen extending along the elongate hollow shaft. A handle is disposed at the shaft proximal end. A connector assembly having a connector assembly proximal end and a connector assembly distal end, the connector assembly proximal and distal ends being opposite ends of the connector assembly. An expandable frame is detachably disposed at the connector assembly distal end, the expandable frame including a plurality of interconnected members formed of an electrically conductive material, wherein the interconnected members in a first portion of the expandable frame are coated with a dielectric layer, and wherein the interconnected members in a second portion of the expandable frame are uncoated and configured as an electrode region of the expandable frame.