JP2006075391A - Evaluation system of degree of arteriosclerosis by determination of blood vessel sound under loading with exercise - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a determining method and an evaluation system for the degree of arteriosclerosis in which no burden is imposed on a patient and which exhibits both of precision and simplicity. <P>SOLUTION: The determining method for the degree of arteriosclerosis uses the measured value of the frequency of the blood vessel sound as an index. The evaluation system and the apparatus for the degree of arteriosclerosis use the determining method. A technique is provided which measures the frequency of the blood vessel sound (Korotkoff sound) by attaining the simplicity and speediness of measuring and which uses increase in the peak frequency of the power spectrum of the frequency of the blood vessel sound with the advance of the arteriosclerosis as an index. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an arteriosclerosis degree quantification method using a measurement value of blood vessel sound as an index, and an arteriosclerosis degree evaluation system or an evaluation apparatus using the quantification method.

Arteriosclerosis increases with aging, and its index or risk factor is known in a wide variety such as hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia and the like. Moreover, the arteriosclerosis index (ratio of HDL cholesterol value in the total cholesterol value) calculated based on the quantitative result of the blood test is commonly used in health examinations.

Furthermore, a method for evaluating the degree of arteriosclerosis by measuring the arterial pulse wave velocity is known (Patent Document 1). In this method, the pulse wave of the arteries of both arms and both legs is recorded simultaneously with the measurement of the phonocardiogram and blood pressure, and the propagation speed of the pulse wave is measured. This measurement is performed in a resting state.
JP 2004-49331 A

Since arteriosclerosis is used as one of the indexes related to diseases of important organs such as the brain and heart, if the degree of arteriosclerosis can be evaluated on a daily basis, the effect on health management is high. However, in the conventional evaluation method, it is necessary to attach a measuring instrument to the whole body in blood collection or in a resting state, and there is a defect that the burden on the subject is large and not easy.

An object of the present invention is to provide an arteriosclerosis quantification method and evaluation system that does not place a burden on a subject and solves the above-described conventional defects, and also has sufficient accuracy and simplicity. is there.

In order to solve the above-mentioned problems, the present inventor has conducted intensive research for many years, and as a result, regarding the blood vessel sound (Korotkoff sound) used as an index of blood pressure measurement, “the peak frequency of the power spectrum of the blood vessel sound is I found a phenomenon that it increases as the degree of arteriosclerosis increases. Based on this surprising discovery, the present invention has been completed.

According to the present invention, as means for solving the above-described problems, the arteriosclerosis determination method and the arteriosclerosis evaluation system described in the following (1) to (8) are provided:
(1) A method for determining the degree of arteriosclerosis using the measured value of blood vessel sound as an index;
(2) The method for quantifying the degree of arteriosclerosis according to (1), wherein the index is a measurement value of blood vessel sound under exercise load;
(3) The method for determining the degree of arteriosclerosis according to the above (1), wherein the index is a measurement value of both blood vessel sounds at rest and under an exercise load, and is calculated based on a comparison of these two measurement values;
(4) The method for quantifying the degree of arteriosclerosis according to (1) to (3) above, wherein the measurement target used as an index is at least one kind of sound selected from the frequency or wavelength, wave height and waveform of blood vessel sound;
(5) The method for determining the degree of arteriosclerosis according to the above (1) to (4), wherein the index is the frequency of the blood vessel sound and is calculated based on the peak frequency of the measured power spectrum of the frequency;
(6) (A) a step of applying exercise, (B) a step of controlling the blood flow of at least one region selected from the upper limbs and the lower limbs by applying and reducing pressure under exercise, (C) exercise load The method for quantifying the degree of arteriosclerosis according to (1) to (5), comprising: a step of measuring a blood vessel sound under blood flow control; and (D) recording and analyzing the measurement value.
(7) (A) Means for loading exercise, (B) Means for controlling blood flow in at least one region selected from the upper limb and lower limb portions by pressurization and decompression, (C) Blood vessel sound under blood flow control And (D) an evaluation system for the degree of arteriosclerosis characterized by comprising means for recording and analyzing the measured value; and (8) the means for loading the exercise is an electric braking type bicycle ergometer. (7) The arteriosclerosis evaluation system.

(1) Since the arteriosclerosis quantification method and evaluation system according to the present invention measures under conditions where blood flow velocity and blood pressure are amplified by exercise load, it can capture even minute changes that cannot be detected in a resting state. It is.
(2) A blood vessel sound can be measured by a method similar to conventional blood pressure measurement. Therefore, since blood collection and attachment of a measuring instrument to the whole body are not required, the subject is not burdened, and it is simple, labor-saving, and economical from the viewpoint of cost, labor, and time required.
(3) Since it is simple, it is easy to combine with physical fitness evaluation, and can be added or combined as one of the evaluation items in one exercise test, preventing arteriosclerosis, prolonging life and health Contributes greatly to the maintenance, management, and promotion of

Measurement of blood vessel sound: For measurement, at least one selected from the frequency, frequency, wavelength, wave height, and waveform of the blood vessel sound, for example, only the frequency, the combination of the frequency and the waveform, the frequency, the wavelength, A combination of three of the waveforms can be used.
In particular, when using a frequency, as described above, the peak frequency of the power spectrum of the blood vessel sound frequency increases as the degree of arteriosclerosis increases, so that the frequency itself is used as a quantitative index of the degree of arteriosclerosis. It is desirable.

Pressurization and decompression of blood vessels: By loosening the pressure of the pressurized blood vessels, the blood vessels are slightly opened, and the blood flow that flows out of the gaps becomes turbulent, and blood vessel sounds are generated. In addition, the blood vessel sound is affected by the hardness of the blood vessel wall. Therefore, pressurization and decompression on the blood vessel enables quantitative measurement of the difference in arteriosclerosis by analyzing the peak frequency of the blood vessel sound power spectrum.

Exercise load: The peak frequency of the blood vessel sound is more conspicuous in the state where the blood flow velocity and blood pressure are amplified by the exercise load than at rest. In addition, the exercise load enables capture of minute changes that cannot be detected in a resting state, and increases the detection sensitivity of blood vessel sounds. Therefore, it is desirable to measure blood vessel sound under exercise load. It should be noted that the exercise load on the subject is preferably kept within the range of 110 to 130 beats / minute, where the stroke volume per one heartbeat reaches a maximum.

Arteriosclerosis evaluation system: its configuration is shown in FIG. This system includes a pressure-reducing zone 1 that suppresses blood flow in the upper limbs and lower limbs of a living body, for example, the upper arm by pressurization and decompression, and measurement of blood vessel sound generated inside a blood vessel in which blood flow is controlled. A sound device 2 and an analysis device 3 for recording and analyzing data obtained by the sound measurement device are provided.

Pressurized and depressurized band 1: Manchette (a long and slender cloth band with a built-in rubber bag) used for blood pressure measurement or a similar band can be used.

Sound measuring device 2: A normal microphone or a device specialized in heart sound measurement, such as a heart sound microphone (MA-250; manufactured by Fukuda Denshi Co., Ltd.) can be used.

Analysis device 3: An AD converter 4 that converts an analog signal input from the sound measuring device 2 into a digital signal and outputs the digital signal, and a computer 5 that performs frequency analysis of an acoustic signal input through the AD converter.

Operation of pressurization and depressurization zone 1: A mechanism for pressurization and depressurization can be provided by a pressure control device 6 that operates in conjunction with the computer 5.
<Reference example>

Model of generation of blood vessel sound: A schematic diagram is shown in FIG.

The blood vessel 7 pressurized by the pressurization / decompression zone 1 loosens the pressure of the pressurization / decompression zone, so that the blood vessel opens slightly, the blood flow flowing out from the gap becomes turbulent, and the blood vessel sound 8 is generated. .

The blood vessel sound 8 is measured by the sound measuring device 2 installed downstream of the blood vessel 7 pressurized by the pressurization / decompression zone 1.

Hereinafter, the contents of the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

The arteriosclerosis degree can be quantified and evaluated by measuring the frequency of the blood vessel sound using the arteriosclerosis evaluation system (FIG. 1).

The exercise load on the subject is pedaled by an electric braking type bicycle ergometer, and is increased by the incremental load method starting from 10 watts.

The exercise time is 3 minutes for each load, and the blood vessel sound is measured in the last 1 minute (from 2 minutes to 3 minutes) where the heart rate is considered to have reached a steady state.

The blood vessel sound in the range of heart rate 110-130 beats / minute, at which the stroke volume per one heartbeat reaches the maximum, is recorded and analyzed, and the peak frequencies are compared.

Since the peak frequency increases depending on the degree of arteriosclerosis, for example, if the peak frequency value is 180 Hz or less, it is evaluated as a normal level, if it is in the range of 180-240 Hz, it is evaluated as a caution level, and if it is 240 Hz or more, it is evaluated as a warning level. .

Medical equipment for medical checkup based on quantitative evaluation of arteriosclerosis, health equipment for health maintenance / management / promotion, home medical equipment for prevention of arteriosclerosis, sports measuring equipment, etc.

It is the figure which showed the structure of the evaluation system of an arteriosclerosis degree. It is the figure which showed the model of generation | occurrence | production of the blood vessel sound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pressurization decompression zone 2 ... Sound measuring device 3 ... Analysis device 4 ... AD converter 5 ... Computer 6 ... Pressure control device 7 ... Blood vessel 8 ... Blood vessel sound

Claims (8)

A method for quantifying arteriosclerosis, characterized by using a measured value of blood vessel sound as an index. The method for quantifying the degree of arteriosclerosis according to claim 1, wherein the index is a measured value of blood vessel sound under exercise load. The arteriosclerosis quantification method according to claim 1, wherein the index is a measurement value of both blood vessel sounds under rest and exercise load, and is calculated based on a comparison between the two measurement values. The method for quantifying the degree of arteriosclerosis according to claim 1, 2 or 3, wherein the measurement target used as an index is at least one sound property selected from the frequency or wavelength, wave height and waveform of blood vessel sound. The method for quantifying the degree of arteriosclerosis according to claim 1, 2, 3, or 4, wherein the index is a frequency of a blood vessel sound, and the index is calculated based on a peak frequency of a measured power spectrum of the frequency. (A) a step of applying exercise, (B) a step of controlling the blood flow of at least one region selected from the upper limb and the lower limb portion by applying pressure and reducing pressure under the exercise load, and (C) under the exercise load, The quantification of the degree of arteriosclerosis according to claim 1, 2, 3, 4, or 5, comprising the step of measuring a blood vessel sound under blood flow control, and (D) recording and analyzing the measured value. Method. (A) Means for loading exercise, (B) Means for controlling blood flow in at least one region selected from upper and lower limbs by pressurization and decompression, (C) Measuring blood vessel sound under blood flow control And (D) a system for evaluating the degree of arteriosclerosis, characterized by comprising means for recording and analyzing the measured value. 8. The arteriosclerosis evaluation system according to claim 7, wherein the means for applying exercise is an electric braking type bicycle ergometer.

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