In Vitro Thrombogenicity Testing Apparatus with Controlled Blood Loops
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Solution Overview
Problem
Current in vivo methods for testing medical device thrombogenicity are plagued by anatomy and animal variability, limited data sets, and the need for euthanizing test animals, lacking consistent controls for comparison.
Innovation Solution
An in vitro apparatus and method using a controlled enclosure with heating and temperature feedback, positive and negative thrombogenicity control rods, and thrombogenicity test loops to evaluate medical devices, allowing for reduced animal use and consistent thrombogenic response comparison.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in vivo testing in canine model is used, then thrombogenicity can be tested, but animal variability and anatomy differences cause inconsistent results
Solution Approach 1:
The patent creates a simplified in vitro model that copies the essential physiological conditions of in vivo blood flow and thrombogenicity without using actual animals. The apparatus uses artificial blood loops and controlled flow conditions to replicate the thrombogenic environment, eliminating animal variability while maintaining test validity
Solution Approach 2:
The invention changes the testing parameters from living biological systems to controlled physical-chemical parameters. By controlling temperature, flow rate, and blood composition in the in vitro system, the patent achieves consistent thrombogenicity testing without the variability inherent in animal models
2Measurement precision
If in vivo testing is performed, then thrombogenicity data can be obtained, but limited data sets and lack of controls reduce test quality
Solution Approach 1:
The patent segments the testing system into multiple independent blood loops (typically 3-5 loops), each providing independent thrombogenicity data. This segmentation allows for repeated measurements and statistical analysis, greatly increasing the data set size and measurement precision compared to single animal studies
Solution Approach 2:
The in vitro apparatus incorporates controlled feedback mechanisms for temperature regulation and flow rate control, ensuring consistent testing conditions across all loops. This controlled environment provides more reliable and precise measurements than uncontrolled in vivo conditions
3Reliability
If in vivo thrombogenicity studies are conducted, then medical device safety can be assessed, but test animals must be euthanized
Solution Approach 1:
The patent replaces the living animal system with an artificial in vitro copy that maintains blood circulation and thrombogenicity functions. This copying approach eliminates the need for animal euthanasia while preserving the ability to assess medical device safety through thrombogenicity testing
Solution Approach 2:
The invention introduces an intermediary in vitro blood circulation system that mediates between the need for safety assessment and the ethical concern of animal euthanasia. This intermediary system provides the necessary testing functionality without requiring living animals
4Measurement precision
If conventional in vivo testing is used, then thrombogenicity can be evaluated, but lack of consistent controls for comparison reduces test reliability
Solution Approach 1:
The patent segments the testing system into distinct control loops, including positive controls (thrombogenic surfaces), negative controls (non-thrombogenic surfaces), and test article loops. This segmentation provides consistent control groups for comparison while maintaining manageable system complexity through modular design
Solution Approach 2:
The in vitro apparatus uses homogeneous testing conditions across all loops, with consistent temperature control, flow rates, and blood composition. This homogeneity ensures that comparisons between control groups and test articles are valid and reliable
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
This approach reduces animal variability, eliminates the need for animal euthanasia, and provides consistent controls for evaluating thrombogenicity, enabling more controlled and humane testing of medical devices.
Implementation Method 1
a heating element thermally coupled to the enclosure
Implementation Method 2
a temperature feedback circuit operably coupled to the heating element and configured to control the heating element to maintain an interior of the enclosure within a preset temperature range
Implementation Method 3
a peristaltic pump; and a tubing loop, wherein a first portion of the tubing loop is positioned within the peristaltic pump
Data Source
AI summary
An apparatus for in vitro testing of medical device thrombogenicity includes an enclosure; a heating element thermally coupled to the enclosure; and a temperature feedback circuit operably coupled to the heating element and configured to control the heating element to maintain an interior of the enclosure within a preset temperature range. Positive, negative, and intermediate control rods are provided as standards against which to compare a medical device test article. Multiple blood test loops can be established through the enclosure using a common blood supply. The medical device test article can be placed in one of the loops, while the remaining loops can contain controls. Blood can be circulated through the test loops at a flow rate similar to that encountered in vivo, and thrombus formation can be assessed thereafter.