Sheathed Embolization Device for Foam Particulate Containment
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Solution Overview
Problem
Current endovascular devices for left atrial appendage closure face challenges such as air embolism, pericardial effusions, tissue tearing, device embolization, and stroke, primarily due to the lack of effective volume filling occlusion and the risk of particulate generation during delivery.
Innovation Solution
A sheathed embolization device (SED) comprising SMP foam encapsulated within a membrane to provide rapid clotting, endothelialization, and tissue ingrowth, integrated with nitinol for fluoroscopic guidance, and a detachment mechanism to mitigate particulate generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SMP foam is used for embolization device, then rapid clotting and occlusion are achieved, but foam particulates are generated during delivery
Solution Approach 1:
A flexible membrane sheath is applied around the SMP foam to encapsulate it. This membrane acts as a barrier that prevents foam particulates from detaching and entering the bloodstream during delivery, while still allowing the foam to expand and achieve rapid occlusion of the left atrial appendage.
Solution Approach 2:
The membrane serves as an intermediary layer between the SMP foam and the bloodstream. It mediates the interaction by blocking direct contact between foam particulates and blood, thereby preventing embolization while maintaining the therapeutic occlusion function.
2Reliability
If conventional closure devices are used, then LAA closure is achieved, but adverse events like air embolism and tissue tearing occur
Solution Approach 1:
The flexible membrane sheath surrounding the SMP foam provides a protective interface that reduces mechanical stress on surrounding tissues during deployment. This membrane-based approach minimizes tissue tearing and eliminates air embolism risks associated with conventional rigid closure devices.
3Ease of operation
If SMP foam is compressed to fit inside catheter, then delivery is enabled, but volume expansion is required for occlusion
Solution Approach 1:
The SMP foam utilizes shape memory polymer properties to undergo a phase transition from a compressed low-volume state (for delivery) to an expanded high-volume state (for occlusion). The foam is programmed with a specific expansion ratio that activates when exposed to body temperature, enabling it to fill the LAA cavity effectively after delivery through the catheter.
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 SED achieves improved occlusion times, reduces adverse events like device thrombosis and migration, and effectively captures foam particulates, enhancing the safety and efficacy of LAA closure procedures.
Implementation Method 1
SMP foams are capable of being compressed to fit inside a catheter and then actuating once exposed to body heat and water inside vasculature, achieving up to a 70-fold volume expansion
Implementation Method 2
The material is heated above its glass transition (Tg) temperature, and an external stress is applied to deform the material to its secondary shape
Implementation Method 3
The porous architecture of the foams provides a large surface area for rapid clotting and connective tissue infiltration
Implementation Method 4
A thin flexible membrane that fully encapsulates the SMP foam... effectively captures foam particulates
Data Source
AI summary
An embodiment includes an apparatus comprising: a shape memory polymer (SMP) foam having an outside surface; and a membrane that encapsulates at least 50% of the outside surface of the SMP foam; wherein (a) the SMP foam includes a thermoset SMP, and (b) the membrane includes a thermoplastic polymer. Other embodiments are addressed herein.