Arterial Stiffness Evaluation Using Cuff Pressure and Pulse Wave Analysis
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Solution Overview
Problem
Conventional methods for evaluating arterial-wall stiffness require specialized facilities and knowledge, are invasive, and lack accuracy, making it difficult for individuals to assess vascular stiffness conveniently and reliably at home.
Innovation Solution
An arterial-wall stiffness evaluation system using a cuff with a pressure sensor to estimate the pressure-diameter characteristic curve, differentiating and numerically integrating pulse waves to assess vascular stiffness, employing arctan or sigmoid functions for robustness against body motion and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional diagnostic imaging ultrasonic apparatus or pulse-wave transmission velocity measurement is used, then measurement precision of arterial stiffness is improved, but device complexity and ease of operation deteriorate due to requiring large apparatuses and specialized knowledge
Solution Approach 1:
The patent replaces complex mechanical diagnostic imaging systems with a simplified pneumatic-cuff-based measurement system. Instead of using ultrasonic apparatus or pulse-wave transmission velocity measurement equipment, the invention uses a cuff to apply external pressure and detect pulse wave characteristics, thereby achieving arterial stiffness measurement with simpler, more accessible equipment that can be used in home settings.
Solution Approach 2:
The patent introduces a cuff as an intermediary device between the measurement system and the artery. The cuff applies controlled external pressure and serves as a mediator to detect pulse wave characteristics, enabling indirect but accurate measurement of arterial stiffness without requiring direct contact with or complex imaging of the vessel wall.
2Ease of operation
If cuff-based pulse wave amplitude measurement is used, then ease of operation is improved, but measurement precision deteriorates due to not considering vascular wall characteristics
Solution Approach 1:
The patent changes the measurement parameters from simple pulse wave amplitude to a combination of pulse wave amplitude and external pressure applied by the cuff. By measuring how pulse wave amplitude varies with different cuff pressures, the system captures vascular wall characteristics and achieves more precise stiffness evaluation while maintaining operational simplicity.
Solution Approach 2:
The patent applies excessive action by using cuff pressure that exceeds normal physiological conditions to deliberately alter vascular wall characteristics. By applying varying degrees of external pressure beyond normal ranges, the system can observe how the vascular wall responds and calculate stiffness parameters more accurately.
3Ease of operation
If estimated function is used to derive transmural pressure and vascular diameter relationship, then ease of operation is improved, but measurement precision deteriorates due to dependency on estimated function accuracy
Solution Approach 1:
The patent introduces feedback by using the measured pulse wave characteristics under different cuff pressures to iteratively refine the estimation of arterial stiffness parameters. The system continuously adjusts its calculations based on the observed relationship between external pressure and pulse wave amplitude, thereby reducing dependency on pre-assumed functions and improving measurement accuracy.
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
Enables accurate, non-invasive, and convenient evaluation of arterial-wall stiffness at home without specialized knowledge, providing a more reliable assessment than conventional techniques and reducing temporal restrictions.
Implementation Method 1
a pressure sensor for detecting pressure in the cuff
Data Source
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AI summary
An arterial-wall stiffness evaluation system of the present invention includes: a cuff to be attached to a part of a living body; a pressure sensor for detecting pressure in the cuff; a cuff-pressure control section for controlling the pressure in the cuff to be increased or decreased up to a predetermined value, based on a value detected by the pressure sensor; and a data processing section for calculating, based on pulse waves detected by the pressure sensor, pulse-wave amplitudes of cuff-pressure pulse waves and blood-pressure pulse waves, and for evaluating arterial-wall stiffness based on the pulse-wave amplitudes. The arterial-wall stiffness is evaluated by a pressure-diameter characteristic curve, which represents a relationship between vascular diameter and transmural pressure applied to a vascular wall, or by estimation from shapes and amplitudes of the detected pulse waves. Alternatively, the evaluation is performed by estimating, from the detected pulse waves, a differential function obtainable by differentiating a pressure-diameter characteristic curve with respect to a transmural pressure, or by use of an arctan or a sigmoid function. This allows anybody to easily evaluate blood vessel stiffness anytime with high accuracy even at home without any special knowledge.