Plasma Volume Variation Assessment for Heart Failure Monitoring

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Solution Overview

Problem

Current methods for evaluating congestion in heart failure patients are imprecise and lack sensitivity, particularly in outpatients, as they rely on physical examination and BNP or NT pro-BNP measurements that are highly variable and influenced by kidney function and age, necessitating a more reliable method for monitoring plasma volume variation.

Innovation Solution

A method for determining plasma volume variation in vitro using human parameters such as hemoglobin and hematocrit levels, with formulas like the Strauss formula, to assess cardiovascular risk by comparing variations to a reference value, and a device for measuring and alerting on potential cardiovascular events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If physical examination and BNP/NT pro-BNP measurements are used to evaluate congestion in heart failure patients, then the evaluation can be performed routinely, but the precision and sensitivity of the evaluation deteriorates

Engineering Contradiction:
Improveroutine evaluationVSAvoidcongestion evaluation precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention changes the measured parameter from BNP/NT pro-BNP levels to plasma volume variation (calculated from hemoglobin and hematocrit changes). This parameter transformation provides a more precise and reliable indicator of congestion status that is not influenced by kidney function or age, thereby resolving the contradiction between routine evaluability and measurement precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces plasma volume variation as an intermediary parameter that connects routine blood tests (hemoglobin, hematocrit) with accurate congestion assessment. This intermediary enables precise monitoring of plasma volume changes without requiring complex imaging or being affected by confounding factors, thus improving measurement precision while maintaining ease of operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If BNP or NT pro-BNP measurements are used to assess congestion, then the evaluation can be performed in outpatients, but the reliability deteriorates due to high variability and specificity problems

Engineering Contradiction:
Improveoutpatient assessment capabilityVSAvoidcongestion assessment reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention transforms the assessment parameter from hormone levels (BNP/NT pro-BNP) to plasma volume variation derived from routine hematology parameters. This change eliminates the variability and specificity issues inherent in BNP measurements while maintaining outpatient applicability, as hemoglobin and hematocrit are stable, routine parameters not influenced by kidney function or age

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses routinely available blood parameters (hemoglobin, hematocrit) as proxies to infer plasma volume variation. By copying information from standard blood tests that are already performed in outpatient settings, the method achieves reliable congestion assessment without requiring specialized tests, thus maintaining versatility while improving reliability

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2721418B1Method for determining a plasma volume variation and devices for implementing the method
Publication Date: 2020.08.26 INST NAT DE LA SANTE & DE LA RECHERCHE MEDICALE (INSERM)
  • EP2721418B1 patent drawingFigure 1A
  • EP2721418B1 patent drawingFigure 1B
  • EP2721418B1 patent drawingFigure 1C

AI summary

Method for monitoring the evolution of heart failure in a patient comprising determining in vitro a physiological human parameter in a patient, comprising the steps consisting of: i) measuring values of two or more human parameters (P1, P2,..PN) at time t1 wherein one or more of the human parameters (P1 t1, P2 t1,..PN t1) is obtained from a human physiological fluid sample, ii) measuring values of the same two or more parameters (P1 t2, P2 t2,..PN t2) at time t2 different from time t1, and iii) determining the physiological human parameter wherein the physiological human parameter is a plasma volume variation ?V between time t2 and time t1 from the values (P1 t1, P2 t1,..PN t1, P1 t2, P2 t2,..PN t2) obtained at times t1 and t2, and devices for implementing said method.