LVAD Thrombus Detection via Power Trend Analysis

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Solution Overview

Problem

Determining adverse events in patients with implanted ventricular assist devices (VADs) is challenging due to issues with sensor calibration, power consumption, and sensitivity, often leading to false alarms and increased morbidity.

Innovation Solution

A method using low-pass filters to calculate power consumption trends, determine differences, and generate alarms when thresholds are exceeded, including short-term and long-term trends, and speed-dependent thresholds to detect adverse events such as thrombus and other conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors are implanted into or onto the VAD to detect operating parameters, then adverse events can be detected, but sensor calibration is subject to failure from corrosion and increases power consumption

Engineering Contradiction:
Improveadverse event detectionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent replaces physical sensors with a computational method that uses existing power consumption data from the VAD's motor controller. Instead of implanting additional sensors to detect thrombus formation, the system analyzes changes in power consumption patterns through signal processing algorithms, eliminating the need for extra sensing hardware and its associated calibration and power requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The VAD's existing power consumption measurements, already taken for motor control purposes, are repurposed to detect adverse events. The system uses the motor controller's existing data acquisition capability to monitor power consumption and apply filtering algorithms, allowing the device to self-diagnose thrombus formation without additional sensors or power expenditure.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If sensors are implanted to detect adverse events, then detection capability is improved, but the system becomes more complex with calibration requirements

Engineering Contradiction:
Improveadverse event detection sensitivityVSAvoidsensor calibration system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from physical sensors and implements it through software-based analysis of power consumption data. By removing the sensor hardware and its calibration infrastructure, the system achieves adverse event detection capability while significantly reducing device complexity and eliminating calibration requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using physical sensors to directly measure thrombus-related parameters, the system creates a computational model that correlates power consumption patterns with thrombus formation. The algorithm analyzes deviations in power consumption from expected patterns, effectively copying the detection function through mathematical modeling rather than direct physical measurement.

Inventive Principle:
Principle #26Copying

3Device complexity

If simple detection methods are used, then device complexity is reduced, but sensitivity is insufficient and false alarms increase

Engineering Contradiction:
Improvedetection systemVSAvoiddetection sensitivity
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the power consumption signal into different frequency components using filtering techniques. By applying low-pass filters with specific cutoff frequencies, the system separates relevant thrombus-related power variations from noise and normal operational fluctuations, enhancing detection sensitivity while maintaining computational simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts detection thresholds based on analyzed power consumption trends rather than using fixed thresholds. The algorithm adapts to normal variations in power consumption patterns and only triggers alerts when deviations exceed dynamically determined limits, reducing false alarms while maintaining high sensitivity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20220032035A1Early warning of lvad thrombus formation
Publication Date: 2022.02.03 BOSTON SCIENTIFIC SCIMED INC
  • US20220032035A1 patent drawing
  • US20220032035A1 patent drawing
  • US20220032035A1 patent drawing

AI summary

A method of determining an adverse event within a patient having an implantable blood pump including calculating a plurality of power consumption trends of the blood pump during a plurality of time periods using a low-pass filter, determining a plurality of power trend differences between the plurality of power consumption trends, calculating a total amount of the plurality of power trend differences during a time interval, and generating an alarm when the total amount of the plurality of power trend differences exceeds a pre-determined threshold.