Embolus Filter with Upstream Basket and Nitinol Anchors
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Solution Overview
Problem
Existing blood clot filters increase pressure on blood vessel walls and can completely block blood flow when filled with emboli, leading to vascular injury or disease.
Innovation Solution
A blood filter design featuring a filter basket positioned upstream from anchor members, with retainer members to limit radial expansion and prevent increased stress on the vessel walls, allowing for emboli capture without blocking blood flow, using shape memory alloys like Nitinol for the anchor and filter members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter basket is positioned downstream with anchor members forming the first filtering zone, then the filter can be anchored securely to the vessel wall, but the captured emboli increase stress on the blood vessel walls and can completely block blood flow
Solution Approach 1:
The filter is divided into two separate filtering zones: a first filtering zone formed by anchor members for initial emboli capture, and a second filtering zone formed by locator members positioned upstream. This segmentation allows emboli to be captured in the upstream second zone before reaching the anchor members, preventing stress concentration on the vessel wall while maintaining secure anchoring in the first zone.
Solution Approach 2:
The filter utilizes the longitudinal dimension of the vessel by positioning filtering zones at different locations along the blood flow path. The second filtering zone (locator members) is positioned upstream in the longitudinal dimension, allowing it to intercept emboli before they reach the first filtering zone (anchor members) that are engaged with the vessel wall, thereby solving the stress and blockage problem while maintaining anchoring security.
2Quantity of substance
If the filter basket expands radially to capture more emboli, then the filtering capacity increases, but the stress on the blood vessel walls increases leading to vascular injury
Solution Approach 1:
The filtering function is segmented between two distinct structures: anchor members that provide secure attachment to the vessel wall with minimal radial expansion, and locator members that form the second filtering zone with increased radial expansion capacity. This segmentation allows the locator members to expand radially and capture emboli without transmitting significant stress to the vessel wall, as they are not anchored directly to it.
Solution Approach 2:
The locator members act as an intermediary structure between the blood flow and the anchor members. They intercept and capture emboli in the second filtering zone, preventing emboli from reaching the anchor members and reducing the load on the vessel wall. The locator members absorb the emboli capture function while the anchor members maintain the structural connection to the vessel.
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 emboli without applying additional stress to the blood vessel walls and prevents complete blockage of blood flow, even when filled, by positioning the filter basket upstream and using Nitinol to manage expansion and anchoring forces.
Implementation Method 1
using shape memory alloys like Nitinol for the anchor and filter members
Data Source
AI summary
A blood filter device for placement in a blood vessel including a plurality of anchor members disposed radially and extending angularly about a first hub. A filter basket is preferably positioned upstream from the anchor members. The anchor members each include a hook configured to penetrate the vessel wall to prevent longitudinal movement due to blood flow. The filter basket is made up of a number of filter members configured to retain blood clots within the basket without completely blocking blood flow or applying additional force to vessel walls. Portions of the filter members may project radially outward to position the basket near the vessel centerline, but the filter basket preferably does not include hooks or anchors for anchoring the filter basket to the blood vessel.