Noninvasive Aortic Pulse Wave Velocity Measurement via Acoustic Transit Time
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Solution Overview
Problem
Conventional methods for measuring aortic pulse wave velocity are invasive, require manual estimation of distance, and lack high accuracy and cost-effectiveness, limiting their applicability and precision in vascular disease diagnosis and cardiovascular event prediction.
Innovation Solution
A non-invasive method using pulse wave sensors and acoustic actuators/sensors attached to the skin surface near the aorta, where the pulse wave velocity is determined by calculating the transit time of both pulse waves and acoustic signals, allowing for precise and continuous measurement without manual distance estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional invasive methods are used to measure aortic pulse wave velocity, then measurement accuracy may be improved, but patient comfort and safety deteriorate due to mechanical manipulation of the artery system
Solution Approach 1:
The patent replaces mechanical pulse wave sensors with acoustic sensors that detect pulse waves through sound waves. The acoustic sensor listens to the blood flow sounds in the aorta, eliminating the need for mechanical contact with the artery wall while maintaining measurement capability. This substitution resolves the contradiction by removing the harmful mechanical manipulation while preserving the ability to measure pulse wave velocity accurately.
2Measurement precision
If manual distance estimation is used in conventional methods, then device complexity is reduced, but measurement precision deteriorates due to lack of accurate distance measurement
Solution Approach 1:
The patent introduces acoustic signals as an intermediary to indirectly measure the distance between the aortic valve and measurement points. By measuring the transit time of acoustic signals (which travel at known speed through tissue) and using this to calculate distance, the system achieves accurate distance measurement without requiring direct mechanical measurement tools, thus maintaining simplicity while improving precision.
3Measurement precision
If invasive catheter-based methods are used, then direct aortic measurement is achieved, but ease of operation deteriorates due to requiring medical interventions
Solution Approach 1:
The patent extracts the measurement function from the invasive catheter-based system and implements it through external acoustic sensing. The acoustic sensor is placed on the skin surface and listens to the aortic sounds through the body wall, extracting the pulse wave information without requiring insertion into the vascular system. This makes the procedure as simple as placing a sensor on the skin, comparable to an ECG, while maintaining the ability to measure direct aortic parameters.
4Measurement precision
If conventional pulse wave sensors are used, then device simplicity is maintained, but measurement precision deteriorates due to inability to accurately determine signal path length
Solution Approach 1:
The acoustic sensor serves multiple functions: it detects the pulse wave signals from the aorta, measures the transit time of acoustic signals for distance calculation, and provides timing references for synchronization. This multi-functionality allows the system to achieve accurate pulse wave velocity measurement by combining distance information from acoustic transit time with pulse wave timing, without requiring separate dedicated components for each measurement task.
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 method provides a cost-effective, high-accuracy, and non-invasive means to measure aortic pulse wave velocity, enabling precise long-term monitoring and prediction of cardiovascular events, with the ability to measure vital parameters and avoid mechanical manipulation of the artery system.
Implementation Method 1
determination of a signal path of the at least one acoustic signal between the at least one third location and the at least one fourth location from the runtime of the at least one acoustic signal
Implementation Method 2
detection of at least one pulse wave in the aorta of the person being measured by at least one of the first pulse wave sensors at the respective first location and determination of the time of detection
Data Source
Figure 1~2
AI summary
In the case of a measurement method and in a measuring apparatus for noninvasively measuring the aortal pulse wave velocity of a test subject (5), i.e. for measuring the propagation velocity of pressure waves in the blood of the aorta (8) of the test object (5), two pulse wave sensors (1, 2) that are applied to different locations on the skin surface of the test subject (5) in the region of the aorta (8) detect the same pulse wave in the aorta (8) of the test subject (5). An acoustic actuator (3) produces an acoustic signal in the region of the first pulse wave sensor (1) and an acoustic sensor (4) detects the acoustic signal in the region of the second pulse wave sensor (2). From the travel time of the acoustic signal, the signal path thereof and hence, approximately, the path of the pulse wave are determined. The aortal pulse wave velocity is determined from the path of the acoustic signal and the travel time of the pulse wave. The pulse wave is preferably detected by bioimpedance measurements. As a result, there is no need for pressure cuffs that are uncomfortable and mechanically influence the arterial system during the measurement. The electrodes of the pulse wave sensors (1, 2) are preferably attached in the region of the heart, in particular at the aortic arch (9), and on an upper thigh of the test subject (5).