Vascular Filter Stability via Segmented Legs and Barbs
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Solution Overview
Problem
Current filters configured to capture blood clots within the vasculature, such as in the inferior vena cava, face challenges in stability and migration within the body lumen, which can lead to ineffective pulmonary embolism prevention and difficulties in removal or repositioning.
Innovation Solution
A filter design featuring a central tubular portion coupled with multiple legs, including barbs and radially expanding filtering zones, which are offset to enhance stability and prevent migration by engaging the lumen wall, and hooks for retrieval, potentially made from shape memory alloys for deployment and compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is designed with multiple legs and barbs to engage the lumen wall for stability, then migration prevention is improved, but device complexity increases
Solution Approach 1:
The filter is divided into multiple legs (typically 6 legs) that extend radially from a central hub. Each leg is independently structured with barbs at its distal end, allowing the filter to engage the lumen wall at multiple discrete points. This segmentation provides stable anchoring while maintaining a relatively simple overall structure composed of repeating modular units.
Solution Approach 2:
The barbs are strategically positioned at the distal ends of the legs, which are the portions of the device that contact the lumen wall. This local concentration of anchoring features at the critical interface with the body provides effective migration prevention without requiring complex structures throughout the entire device. The barbs are oriented to engage the lumen wall in a direction that prevents both proximal and distal migration.
2Ease of operation
If a filter uses shape memory alloys for deployment and compression, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The filter incorporates shape memory alloy materials that change their physical state in response to temperature changes. During delivery, the filter is compressed in a low-temperature martensitic phase that allows it to fit within a narrow catheter. Upon deployment, body temperature triggers a phase transformation to the austenitic phase, causing the filter to automatically expand to its full radial configuration. This parameter change (temperature-induced phase transformation) simplifies the deployment operation while the manufacturing precision is focused on ensuring uniform material composition and heat treatment.
3Reliability
If filtering zones are offset radially to enhance stability, then reliability is improved, but device complexity increases
Solution Approach 1:
The filtering function is segmented across multiple legs that are offset radially around the central axis. Each leg contains filtering zones at its distal end, and the radial offset arrangement ensures that filtering occurs at multiple locations around the lumen circumference. This segmentation provides both mechanical stability through lumen wall engagement and effective clot capture across a distributed filtering surface.
Solution Approach 2:
The filter combines multiple functions into the leg structure: mechanical support, lumen wall engagement via barbs, and clot filtering. The legs serve as structural elements that maintain the filter's radial configuration while simultaneously providing the filtering function through integrated filtering zones. This merging of functions reduces the need for separate components and simplifies the overall device architecture.
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 filter effectively captures blood clots while maintaining stability within the vasculature, minimizing the risk of migration and facilitating easy retrieval or repositioning, thereby preventing pulmonary embolism and ensuring effective placement.
Implementation Method 1
potentially made from shape memory alloys for deployment and compression
Data Source
AI summary
A filter, configured to be disposed within a body lumen, that includes one or more filtering zones. The filter may include one or more sets of legs, configured to interact with the body lumen wall in order to stabilize the position of the filter and to create a filtering structure. In some embodiments the filter may be integrally formed form a single tube of material.