Resilient Loop Anchoring for Vascular Filter Stability
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Solution Overview
Problem
Existing vascular filters face challenges in maintaining proper positioning within vessels due to migration and tilting caused by blood pressure and vessel movement, which can lead to reduced filtering efficiency and vessel damage from anchoring elements.
Innovation Solution
The design incorporates resilient loops with piercing members at the distal ends of filter legs that can adapt to vessel diameter changes, limiting penetration depth and providing stable anchoring while allowing for flexible deployment and retrieval, using shape memory materials like Nitinol for enhanced stability and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If barbs are used as anchoring elements to prevent filter migration, then filter positioning stability is improved, but vessel wall damage increases
Solution Approach 1:
The anchoring element uses a flexible loop structure instead of rigid barbs. The loop is formed from a resilient material that can flex and adapt to the vessel wall, distributing the anchoring force across a larger area and preventing concentrated stress points that cause damage. The loop maintains filter positioning while conforming to the vessel wall geometry.
Solution Approach 2:
The anchoring mechanism changes from a fixed rigid structure to a dynamic resilient structure that can change its physical state. The loop can be compressed to a smaller diameter for delivery, then expands to engage the vessel wall. The resilient material allows the anchoring element to adapt its shape and size in response to vessel movements and pressure changes.
2Strength
If barbs are designed to pierce through the entire vessel wall thickness for secure anchoring, then filter fixation strength is improved, but vessel wall damage increases
Solution Approach 1:
The loop structure engages the vessel wall through a combination of radial compression and friction rather than deep penetration. The resilient material allows the loop to maintain contact pressure against the vessel wall, providing secure fixation without requiring the anchoring element to pierce through the entire wall thickness.
Solution Approach 2:
The invention converts the potential harm of deep penetration into a beneficial shallow engagement mechanism. The loop structure uses the vessel wall's natural elasticity and the loop's resiliency to create a secure anchor that relies on distributed pressure and friction rather than deep penetration, thereby fixing the filter strongly while minimizing damage.
3Stability of the object's composition
If rigid anchoring elements are used to prevent filter tilting, then filter orientation stability is improved, but adaptability to vessel movement decreases
Solution Approach 1:
The anchoring element transitions from a static rigid structure to a dynamic resilient structure. The loop can change its shape and orientation in response to vessel movements, pulsations, and pressure changes while maintaining its anchoring function. This dynamic behavior allows the filter to remain stable relative to the vessel wall despite physiological movements.
Solution Approach 2:
The resilient material allows the loop to change its physical parameters (shape, size, orientation) in response to environmental conditions. The loop can compress, expand, and flex as the vessel moves, maintaining optimal engagement with the vessel wall throughout the range of motion while preventing filter tilting.
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 solution effectively minimizes filter migration and tilting, maintains optimal vessel contact, and allows for easy retrieval by preventing deep penetration and accommodating vessel movement, thus enhancing filtering efficiency and reducing vessel damage.
Implementation Method 1
each loop being a sprung element and providing a vessel abutment surface for limiting the penetration of the piercing member into a vessel wall
Implementation Method 2
using shape memory materials like Nitinol for enhanced stability and adaptability
Data Source
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AI summary
An implantable medical device (10) includes a plurality of legs (16) and, preferably, a circumferential array of support elements (24). The legs (16) have anchoring elements (22) at their distal ends (20). The anchoring elements (22) are formed from a turn (32) of the wire forming the legs (16), while piercing elements (34) are formed by the extremities of the wire. The loops (32) formed in this manner hold the piercing elements (34) in the desired position and orientation during use of the filter assembly (10) and also provide resiliency to counter any effects of movement of the filter assembly (10) caused by movement or changes in the vessel (50) in which the filter assembly (10) is deployed. The anchoring elements (22) can also straighten during removal of the filter assembly (10), thereby facilitating the removal of the filter (10) even after endothelialisation.