RU2377950C2 - Diagnostic technique for vascular remodelling in arterial hypertension - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine namely to cardiology. The sphygmography sensors are established and connected to a recorder for 5-minute recording of sphygmograms. The average pulse wave velocity is determined. The derived data are used to calculate the variation coefficient of the pulse wave velocity to be compared to the reference. Herewith, if the pulse wave velocity exceeds 9.3 m/s, while the variation coefficient of the pulse wave velocity exceeds 9%, vascular remodelling is diagnosed in patients with arterial hypertension.

EFFECT: method allows for higher diagnostic accuracy ensured by consideration of the variation coefficient of the pulse wave velocity.

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Description

The invention relates to medicine and can be used to diagnose vascular lesions in arterial hypertension.

A known method and device for determining blood flow inside a blood vessel [1], which consists in introducing an optical tube into the test vessel. The recorded optical signal is fixed by means of a light detector mounted on the proximal end of the fiber, moreover, to improve the characteristics of the method and device, a fluorescent substance is added to the blood, or effects leading to autofluorescence of the blood are carried out. The method has the following disadvantages. Firstly, it is one of the invasive ones, secondly, the introduction of specialized additives in the blood can lead to undesirable consequences for the patient, thirdly, an abnormality in the optical characteristics of blood flow is recorded in a limited section of a medium-sized vessel.

A known method for assessing the volume distribution of blood flow in vessels [2], based on the use of ultrasound data. According to the materials of the analogue method, to increase the accuracy, ultrasound scanning determines the shock cardiac and shock blood volume of the blood, and the distribution of blood flow is calculated by the formula, and the state of blood flow is estimated by changing the distribution coefficient of blood flow in comparison with the norm. The method allows to solve the task of increasing the accuracy of determining the volume distribution of blood flow in the vessels, but requires ultrasound on expensive equipment and a sufficiently high qualification of the diagnostician. All this limits the possibility of using the claimed method in wide outpatient practice.

A known method for the diagnosis of vascular lesions in arterial hypertension, adopted as a prototype [3] and consisting in the use of sphygmofafia - a method for studying hemodynamics and diagnosis of some forms of pathology of the cardiovascular system, based on the graphic recording of pulse fluctuations in the wall of a blood vessel. The method is as follows. On the patient’s body, pulse sensors are installed that allow the conversion of the perceived mechanical vibrations of the vessel wall (or the accompanying changes in the electrical capacitance or optical properties of the body part under study) into electrical signals. These signals, after preliminary amplification, are fed to a recording device, which is a special prefix to an electrocardiograph or other recorder. Synchronously recorded sphygmograms of the central and peripheral pulse are used to determine the propagation speed of the pulse wave through the arteries; it is calculated as the quotient of dividing the path length of the wave by the duration of the interval between the beginnings of the anacrotic pulse of the studied arteries. So, the pulse wave propagation velocity in the aorta (vessel of elastic type) is calculated by the sphygmogram of the carotid and femoral arteries, in peripheral arteries (vessels of the muscle type) - by volumetric sphygmograms recorded on the shoulder and lower third of the forearm or on the thigh and lower third of the lower leg. The pulse wave propagation velocity depends on the elastic modulus of the arterial wall; it increases with increasing tension of the arterial walls or their compaction. By analyzing the propagation velocity of the pulse wave and comparing it with the norm, a diagnosis of the state of the vessels is carried out.

The main disadvantage of the prototype method is the low accuracy. This is due to the fact that the pulse wave propagation speed (even if the average value is determined for a given period of time) is not a sufficiently informative indicator, since a sample with either large or small deviations from it can correspond to the same average value. Much more informative will be the indicator of the variability of the pulse wave propagation velocity, indicating the deviation of the current value from the average. This indicator is the higher, the greater the number of atherosclerotic plaques, defects in which the thickness of the intima-media complex exceeds 0.9 mm will be detected during diagnosis. A comprehensive analysis of this indicator together with the pulse wave propagation speed allows the most correct and complete assessment of the state of the vascular system in arterial hypertension.

The technical result of the invention is to increase the accuracy of the diagnosis of vascular remodeling in arterial hypertension.

This result is achieved due to the fact that the method for the diagnosis of vascular remodeling in arterial hypertension, which consists in installing sphygmographic examination sensors, connecting them to the recorder, measuring the sphygmograms for five minutes, determining the average pulse wave velocity and comparing the obtained values with the norm, is supplemented by the obtained data determine the coefficient of variation of the propagation velocity of the pulse wave and compare it with the norm, while if the average velocity defamiliarisation pulse wave exceeds 9.3 m / s and the speed variation ratio of pulse wave exceeds 9% in hypertensive patients diagnosed presence of vascular remodeling.

Figure 1 presents a fragment of a sphygmogram explaining the essence of the proposed method. For figure 1, the following notation is introduced: 1 - sphygmogram of the carotid artery; 2 - sphygmogram of the femoral artery; t is the delay time of the pulse wave on the carotid-femoral segment (s).

The diagnostic method is as follows.

To analyze the propagation velocity of the pulse wave, sensitive sensors are installed on the patient's body. To record sphygmograms from the carotid and femoral arteries, sensors are used, one of which is located in the neck at the point of distinct pulsation of the right carotid artery. Registration of the sphygmogram of the femoral artery is carried out using a sensor, the cuff of which is installed in the upper third of the right thigh; the cuff pressure is set at 20-30 mm Hg. Registration of sphygmograms is carried out in the position of the subject lying on his back after an adaptation period of 10-15 minutes. After connecting the sensors to the sphygmographic attachment to determine the propagation velocity of the pulse wave through the vessels of the elastic type, synchronous recording of sphygmograms of the carotid and femoral arteries (carotid-femoral segment) is performed. The recording time is at least 5 minutes. Records are being edited to exclude artifacts. When the number of artifacts that make up more than 10% of the record, re-register the data. After registering the sphygmograms, the data are processed, determining in seconds for each anacrocy the duration of all intervals between the points of the beginning of the rapid rise of the pulse wave in the carotid and femoral arteries (the delay time of the pulse wave on the carotid-femoral segment t in Figure 1). Next, for each measured value of t, the propagation velocity of the pulse wave is calculated by the formula:

C = L / t

where C is the propagation velocity of the pulse wave through the vessels of the elastic type (m / s);

L is the distance between the points of measurement of pulse pressure along the path of blood flow (m).

The distance between the sensor locations is determined by direct measurement on the surface of the body. For the selected sensor installation method, the L value is determined as follows:

L = L2 + L3-L1,

where L1 is the distance from the sensor on the carotid artery to the jugular notch of the sternum;

L2 is the distance from the jugular notch of the sternum to the navel;

L3 is the distance from the navel to the installation site of the sensor on the femoral artery.

The obtained instantaneous values of the velocity Ci are averaged over the entire sample, which makes it possible to calculate the average propagation velocity of the pulse wave Cav.

The next step in the implementation of the method is the determination of the variability of the propagation velocity of the pulse wave.

Parameters such as the average pulse wave velocity (SSR), standard deviation (SD), and the coefficient of variation (CV) of the pulse wave velocity for elastic vessels are calculated.

Statistical time indicators are calculated using the following formulas:

,

,

where SSR (m / s) is the average velocity of the pulse wave during a 5-minute recording.

,

,

where SD (m / s) is the standard deviation of the pulse wave propagation velocity.

,

,

where CV (%) is the coefficient of variation of the pulse wave propagation velocity.

Then, the obtained data are compared with the norm and when the values of the pulse wave propagation frequency Сav are more than 9.3 m / s and the coefficient of variation of the pulse wave velocity CV is more than 9%, patients with arterial hypertension are diagnosed with vascular remodeling.

Studies have shown that the use of the proposed method in some cases allows you to get a positive result.

Example 1

To prove the adequacy of the diagnosis of vascular lesions in terms of pulse wave propagation velocity and pulse wave propagation velocity variability, the diagnostic results were compared using the proposed method and the generally accepted method. 55 patients with arterial hypertension aged 30-60 years were examined. Vascular lesion was confirmed by ultrasound examination of blood vessels according to the criteria of GFCF (thickness of the intima-media complex ≥ 0.9 and / or plaque). By the generally accepted method (without taking into account variability), vascular lesion was detected in 24 people, in 31 patients - it was not detected. The proposed method revealed vascular lesions in most patients with ultrasound signs (coincidence in 41 cases, which is 75%). Thus, the determination of PWV and the variability of PWV can be used to detect vascular lesions in patients with hypertension.

Example 2

Patient S., 55 years old. Diagnosis: Hypertension II Art. AG 2 tbsp. H1.

In the study: pulse wave propagation velocity - 9.65 m / s (> N), pulse wave propagation velocity variability - 10% (> N). According to the results of ultrasound of the common carotid artery, TIM is 1.1 mm (> N).

Example 3

Patient D., 58 years old. Diagnosis: Hypertension II Art. AG 2 tbsp. H1.

In the study: pulse wave propagation velocity - 8.6 (N) m / s, pulse wave propagation velocity variability - 11% (> N). Ultrasound of the common carotid artery - 1.0 mm (> N).

The use of a method for the diagnosis of vascular remodeling in arterial hypertension can increase accuracy and avoid the use of expensive equipment to detect vascular lesions.

Information sources

1. International application No. 90/12537 PCT (WO). Method and device for determining blood flow inside a blood vessel. Stenow E., Teners L., Oberg A.

2. RF application No. 94045540. A method for assessing the volume distribution of blood flow in vessels. Lukyanov V.F., Lukyanova S.V. Publication date 1996.12.29.

3. Vinogradov T.S. Instrumental methods for the study of the cardiovascular system. 1986, Moscow: S.299-372.

Claims (1)

A method for the diagnosis of vascular remodeling in arterial hypertension, including the installation of sphygmographic examination sensors, connecting them to a recorder, five-minute measurement of sphygmograms, determining the average pulse wave propagation velocity and comparing the obtained values with a norm, characterized in that the coefficient of variation of the pulse wave propagation velocity is determined from the obtained data and compare it with the norm, while if the average velocity of the pulse wave exceeds 9.3 m / s and to coefficient of variation of the pulse wave propagation velocity exceeds 9% in hypertensive patients diagnosed presence of vascular remodeling.

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