RU2802128C1 - Method of screening diagnosis of atherosclerosis of brachiocephalic arteries in young and middle-aged men - Google Patents

Abstract

FIELD: medicine; functional diagnostics.

SUBSTANCE: patient is examined using volumetric sphygmography with the definition of diagnostic criteria: cardio-ankle vascular index (CAVI) and right brachial artery augmentation index (R-AI). Diagnosis of atherosclerosis of the brachiocephalic arteries (p) is carried out using previously obtained criteria according to the original mathematical formula. If the p value is equal to or more than 0.5, the patient is diagnosed with the presence of atherosclerosis of the brachiocephalic arteries, and if the p value is less than 0.5, the absence of atherosclerosis of the brachiocephalic arteries is diagnosed.

EFFECT: method enables prompt screening diagnostics of atherosclerosis of brachiocephalic arteries in young and middle-aged men due to the use of objective indicators with the possibility of establishing reference values for arterial stiffness indices.

3 cl, 3 tbl, 1 ex, 1 dwg

Description

The invention relates to the field of medicine, namely to functional diagnostics, and is intended for diagnosing the presence or absence of atherosclerosis of the brachiocephalic arteries (hereinafter referred to as BCA) in young and middle-aged men.

Atherosclerosis of BCA is a disease in which cholesterol plaques clog the largest vessels in the body. The brachiocephalic trunk departs from the aorta and divides into several branches, including the right subclavian, carotid and paravertebral arteries. It is this system that supplies blood to the brain and the right lobe of the shoulder girdle. Therefore, blockage of the brachiocephalic arteries is a direct threat to the life and health of the patient. Moreover, this disease at the initial stages is almost asymptomatic (https://med-ram.ru/diagnostika/ateroskleroz-brahiocefalnyh-arteriy).

Therefore, it is an urgent problem - the development of screening available methods for diagnosing BCA atherosclerosis, which will ensure coverage of a large range of patients without the involvement of complex equipment and highly qualified physicians. This will allow to identify the dangerous condition of the patient at an early, preclinical stage and send this patient for an in-depth examination. Early diagnosis of the presence of atherosclerotic disorders of the BCA is important for maintaining the health of the working population.

Currently, the following methods are used to diagnose atherosclerosis of the BCA: ultrasound examination (ultrasound) of the BCA, computed tomography, magnetic resonance imaging, angiography of the BCA.

The most accessible and frequently used method for diagnosing BCA atherosclerosis in practical healthcare is ultrasound of the BCA. The sensitivity and specificity of ultrasound in detecting stenosis of the BCA (more than 70%) is 99 and 86%, respectively (Kopylov F.Yu., Bykova A.A., et al. Asymptomatic atherosclerosis of the brachiocephalic arteries - modern approaches to diagnosis and treatment. Therapeutic archive. 2017;89(4):95-100. https://doi.org/10.17116/terarkh201789495-100).

As part of the clinical examination, BCA ultrasound is recommended for asymptomatic patients only over 50 years of age in the presence of two or more risk factors: arterial hypertension, dyslipidemia, smoking, family history among close relatives with cases of atherosclerosis up to 60 years of age or cases of ischemic stroke in a family history. Thus, young people of working age remain outside the study, although BCA atherosclerosis is also possible in them.

But this well-known method is not included in the list of studies during periodic medical examination due to time and economic costs. Moreover, it is not provided for in screening studies.

For early diagnosis of BCA atherosclerosis, it is possible to use sphygmomanometry (SPMM) with an assessment of arterial stiffness (Joo HJ, Cho SA, Cho JY, Lee S, Park JH, Hwang SH, Hong SJ, Yu CW, Lim DS. Brachial-ankle pulse wave velocity is associated with composite carotid and coronary atherosclerosis in a middle-aged asymptomatic population J Atheroscler Thromb 2016;23(9):1033-1046 https://doi.org/10.5551/jat.33084). SFMM is a non-invasive, inexpensive, short-term, and easy-to-perform method for vascular assessment.

However, the methodological difficulty of using SPMM lies in the absence of generally accepted reference values for arterial stiffness indices: the cardio-ankle vascular index - CAVI and the augmentation index - AI. Various sources of information indicate different data on the reference values of arterial stiffness indices. For example, when studying the indicators of arterial stiffness, CAVI in healthy individuals ranged from 6.2 to 7.8 depending on age (Sumin A.N., Shcheglova A.V., Fedorova N.V., Artamonova G.V. Values of the cardio-ankle vascular index in healthy individuals of different ages according to the ESSE-RF study in the Kemerovo region, Cardiovascular Therapy and Prevention, 2015;14(5):67-72). Based on this, it is impossible to guarantee a high accuracy in the diagnosis of BCA atherosclerosis by this known method.

The "gold standard", the criterion of reliability in determining stenosing lesions of the BCA is the traditional radiopaque carotid angiography (CAG) (Colin P. Derdeyn. Conventional Angiography Remains an Important Tool for Measurement of Carotid Arterial Stenosis // Radiology 2005 (235) p. 711-713 ). The disadvantages of the known method is that it can examine in detail only the lumen of the arteries, while the accuracy of diagnosing carotid stenosis on angiography in comparison with the data of operations is 89.3%, sensitivity 83.3%, specificity 93.8% (E.M. James, et al., High-resolution dynamic ultrasound imaging of the carotid bifurcation: a prospective evaluation, Radiology, 1982, Vol.144, No. 4, pp. 853-858). CAG has the contrast resolution of digital radiography and cannot always determine the structure of the ASP, does not reveal focal brain lesions. But most importantly, like any intra-arterial invasion, CAG is associated with a risk of complications. Therefore, CAG requires mandatory hospitalization, it cannot be performed on an outpatient basis and used as a screening.

A combination of screening diagnostics of atherosclerosis of the carotid arteries by ultrasonic duplex scanning and assessment of cerebral blood flow by magnetic resonance angiography (MRA) is known (Pokrovsky A.V. Possibilities of modern vascular surgery in the prevention of ischemic stroke. Act speech at the Academic Council of the Institute of Surgery named after A.I. V. Vishnevsky USSR Academy of Medical Sciences. - M.: 1990. - 19 p.). The disadvantages of the known method are: ultrasound has physical limitations, studies in most cases are limited to the visualization of the carotid bifurcation, while the method gives only a subjective assessment of the ASP echostructure, the assessment of the pathological tortuosity of the BCA can be difficult; MRA is prone to artifacts with changes in the speed, nature and direction of blood flow and is limited by the presence of metallic foreign bodies.

From the prior art there are a number of technical solutions aimed at predicting the development of atherosclerosis, but not at diagnosing an already existing disease.

So, from the patent of the Russian Federation No. 2770269, a method is known for predicting the risk of developing subclinical atherosclerosis of the carotid arteries in shift workers in the Arctic. When implementing this known method, the results of daily monitoring of blood pressure and indicators of a biochemical blood test are taken into account. The risk of developing subclinical atherosclerosis of the carotid arteries is calculated using the mathematical formula p = 1/(1+e ^(-F) ). When the p value is less than or equal to 0.606, a low risk of developing subclinical atherosclerosis of the carotid arteries is determined. If the p value is greater than 0.606, a high risk of developing subclinical atherosclerosis of the carotid arteries is determined.

However, this method can only be used for patients in a limited area and is not intended to diagnose the presence or absence of atherosclerosis of the BCA.

There is also a method for predicting the risk of subclinical atherosclerosis of the brachiocephalic arteries in obese women (N.N. Shenkova, N.G. Veselovskaya, et al. Russian Journal of Cardiology No. 4 (144)/ 2017, p. 54-60). The study included 89 women aged 35-59 years (50.6±6.6 years) with abdominal obesity — waist circumference >80 cm. All women underwent duplex examination of the brachiocephalic arteries with determination of the thickness of the intima-media complex (IMCT). The main and additional metabolic risk factors, adipokines of visceral adipose tissue, and ghrelin were determined. The thickness of epicardial fat (EAT) in millimeters was determined by echocardiography. In 32.6% of women, signs of BCA atherosclerosis (IMT more than 1.3-1.5 mm) were revealed. A logistic regression equation was obtained with the most significant set of predictors (ghrelin, CRP, EAT, leptin) associated with subclinical atherosclerosis of BCA in women with obesity, with a percentage of correct prediction of 89.7%.

The disadvantages of this technique include the complexity of its implementation and adaptation exclusively for obese women. In addition, the method is not intended to make a diagnosis of the current presence or absence of BCA atherosclerosis in principle.

At the same time, known methods for screening the diagnosis of atherosclerosis of brachiocephalic arteries in young and middle-aged men have not been identified from the prior art, so it is not possible to make a choice of the closest analogue to the claimed object.

The technical result achieved by the invention is the ability to effectively and quickly screen for atherosclerosis of the brachiocephalic arteries in young and middle-aged men by using only objective indicators with the possibility of establishing reference values for arterial stiffness indices.

The specified technical result is achieved by the proposed method for screening the diagnosis of atherosclerosis of brachiocephalic arteries in young and middle-aged men, according to which the patient is examined using volumetric sphygmography with the determination of diagnostic criteria: cardio-ankle vascular index (CAVI) and right brachial artery augmentation index (R-AI ), and the diagnosis of atherosclerosis of the brachiocephalic arteries is carried out according to a mathematical formula using previously obtained criteria:

p=1/1+e ^{-(-11.82+1.045xCAVI+3.21xR-AI),}

where p is the probability of the presence or absence of atherosclerotic lesions of the brachiocephalic arteries;

e is a mathematical constant equal to 2.72;

CAVI - cardio-ankle vascular index;

R-AI - augmentation index of the right brachial artery;

moreover, when the p value is equal to or more than 0.5, the patient is diagnosed with the presence of atherosclerosis of the brachiocephalic arteries, and when the p value is less than 0.5, the absence of atherosclerosis of the brachiocephalic arteries is diagnosed.

The set technical result is achieved due to the following.

Proposed in the claimed method, diagnostic criteria in the form of indices of arterial stiffness (CAVI and R-AI) allow statistically significant prediction of BCA atherosclerosis. The diagnostic significance of these criteria is not the same, but allows with an accuracy of 81.3% to carry out the diagnosis of BCA lesions when implementing the proposed method.

Cardio-ankle vascular index (CAVI) is an indicator of arterial stiffness, the calculation of which is based on the stiffness parameter β, which does not depend on the level of blood pressure at the time of measurement, with inclusion in the formula of cardio-femoral pulse wave velocity [Shirai K, Utino J, Otsuka K, Takata M. A novel blood pressure-independent arterial wall stiffness parameter; cardio-ankle vascular index (CAVI). J Atheroscler Thromb. 2006; 13(2): 101-107. doi:10.5551/jat.13.101]; [Namba T., Masaki N., Takase B., Adachi T. Arterial Stiffness Assessed by Cardio-Ankle Vascular Index. Int J Mol Sci. 2019; 20(15): 3664. Published 2019 Jul 26. doi:10.3390/ijms20153664]. Moreover, the CAVI cardio-ankle vascular index makes it possible to assess the true stiffness of the vascular wall, regardless of the level of blood pressure.

The augmentation index (R-AI), based on the contour analysis of the sphygmogram, shows the contribution of the reflected pulse wave to the increase in pressure in the proximal arteries. This is also an indicator of the stiffness of the arteries, the higher it is, the stiffer the arteries. In the proposed method, the R-AI augmentation index was determined precisely in the right brachial artery, because the right hand was dominant in patients and therefore the indicated index is the largest in the brachial artery of the dominant hand. This directly affects the accuracy of diagnosis.

It is noticed that with the development of atherosclerosis, the stiffness indicators increase. But in order to objectively establish the presence of atherosclerosis of the brachiocephalic arteries, it is necessary to conduct an ultrasound examination, but this requires more expensive equipment, an ultrasound specialist and more time for diagnosis. The proposed method makes it possible to establish the presence/absence of BCA atherosclerosis in a patient already at the stage of a prophylactic examination and decide on the advisability of sending him for an ultrasound scan. Thus, it is a fast and cost-effective peculiar method of selecting patients for ultrasound examination.

The elastic properties of the vascular wall depend on a variety of risk factors affecting it; therefore, arterial stiffness can be approximately considered as an integral result of all damaging effects on the artery wall. It is believed that indicators characterizing arterial stiffness (including pulse wave velocity in various vascular segments) have different diagnostic significance, requiring statistical justification separately for each stiffness indicator. The CAVI cardio-ankle index, developed by Japanese scientists and implemented in the VaSera VS-1500N sphygmometer, allows in the screening mode to obtain a number of indicators characterizing the state of the arterial bed (CAVI, AI, ABI-ankle-brachial index) for subsequent diagnostic and preventive measures.

In the proposed technical solution for diagnostic purposes, it is proposed to use not absolute values, but relative ones, which are more accurate and cover several objective diagnostic indicators.

From the prior art (RF patent No. 2748715) a "Method for predicting a very high risk of cardiovascular disease in men of the European population aged 40-60 years" is known, which also uses arterial stiffness indices CAVI and AI. However, it should be noted that the proposed method and the specified well-known are fundamentally different, because:

- the known invention and the proposed method have different purposes;

- cardiovascular diseases (ICD-10 code I20-I25) and atherosclerosis (ICD-10 code I70) exist as independent diseases, which is confirmed by the international classification of diseases (ICD-10);

- the well-known invention, in principle, does not allow the diagnosis of atherosclerosis of the BCA, and the proposed solution, in principle, does not allow predicting the risk of cardiovascular diseases in the form of coronary artery disease or heart attack;

- the set of essential features of the known invention (CAVI; AI; patient's age; a mathematical formula using all three parameters and aimed at establishing a possible risk in the future time of occurrence of coronary heart disease or heart attack) differs from the set of essential features of the proposed method (CAVI; R-AI; an original mathematical formula using two parameters and aimed at establishing in the present time the presence or absence of an atherosclerotic lesion of the BCA);

- the achievement of the technical result of each of these solutions is impossible by using a combination of each other's features in their implementation, i.e. they are not interchangeable.

The proposed method allows you to quickly, economically, with sufficient accuracy and without the involvement of a qualified doctor (the proposed method can also be carried out by nursing staff, for example, a nurse) to identify the presence of BCA atherosclerosis in young and middle-aged men aged 22-60 years to speed up the decision on the issue of further in-depth examination and determination of the scope of medical therapy.

When implementing the proposed method, the following operations are carried out in the following sequence:

- male patients aged 22-60 years were selected,

- in these patients, functional indicators were determined by means of volumetric sphygmography: CAVI and R-AI;

- further according to the formula:

p=1/1+e ^{-(-11.82+1.045xCAVI+3.21xR-AI)} the presence or absence of atherosclerotic lesions of the brachiocephalic arteries was established, based on the following: if the p value is equal to or more than 0.5, the patient is diagnosed with atherosclerosis brachiocephalic arteries, and with a p value of less than 0.5, the absence of atherosclerosis of the brachiocephalic arteries.

where e is a mathematical constant equal to 2.72;

CAVI - cardio-ankle vascular index;

R-AI - augmentation index of the right brachial artery;

- depending on the value of the obtained p value, the patient is assigned an in-depth examination on an ultrasound machine and the required medical therapy.

The proposed method for diagnosing BCA atherosclerosis is based on the study of the results of observation during a medical examination of 352 employees of an oil enterprise.

All participants in the study were male, the average age of the surveyed was 38.7±10.2 years (with an age range of 22 to 60 years).

Exclusion criteria: the study did not include persons with a history of coronary heart disease, acute cerebrovascular accident, permanent atrial fibrillation, stage III or more chronic kidney disease, malignant neoplasms. Patients with an ankle-brachial index (ABI) less than 0.9 were also excluded from the study, since the presence of hemodynamically significant stenosis of the arteries of the lower extremities makes it impossible to correctly interpret CAVI.

At the time of the study, 40.8% of surveyed workers smoked.

In the examined group of patients, signs of BCA atherosclerosis were detected in 81 patients (23.0%), while the normal picture of BCA was in 271 patients (77%).

This study was performed in accordance with the ICHGCP rules, in compliance with the ethical standards set forth in the Declaration of Helsinki (2008 edition), the National Standard of the Russian Federation GOST-R 52379-2005 "Good Clinical Practice" (ICH E6 GCP). The study program was approved by the ethics committee of the FBSI "Federal Scientific Center for Medical and Preventive Technologies for Population Health Risk Management" (protocol No. 86 dated May 13, 2019). All patients were informed about the purpose of the study, and voluntary informed consent was obtained.

Arterial stiffness indices were determined using a Fukuda denshi VS-1500 VaSera sphygmograph (Japan). Cardio-ankle vascular index (CAVI) and right brachial artery augmentation index (R-AI) were determined for each patient.

CAVI is a measure of arterial stiffness based on the stiffness parameter β, independent of the blood pressure level at the time of measurement. This index reflects the stiffness of the arterial tree from the aortic root to the ankle. Moreover, the device determines this CAVI on the right and left, but the average is taken for the forecast.

R-AI is the ratio of the pressure at the peak of the reflected wave to the pressure at the peak of the shock wave.

To confirm the accuracy of the proposed method, ultrasound of the extracranial parts of the BCA was performed on an expert-class ultrasound scanner "Vivid iq" (GE Vingmed Ultrasound) using a linear sensor (4.0-13.0 MHz) according to the standard method: Kulikov V.P. Ultrasound diagnosis of vascular diseases: a guide for doctors / V.P. Kulikov / / ed. V.P. Kulikova. M.: STROM, 2011, -512 p.

The presence of an atherosclerotic plaque in the BCA was determined according to the Mannheim consensus: thickening of the intima-media complex (IMC) of 1.5 mm or more, or more than 50% of the thickness of the IMC of the adjacent segments of the artery (Touboul P.J., Hennerici M.G., Meairs S. et al. Mannheim carotid intima-media thickness and plaque consensus (2004-2006-2011). 2004, Brussels, Belgium, 2006, and Hamburg, Germany, 2011. Cerebrovasc Dis. 2012;34(4) : 290-296 doi:10.1159/000343145).

Statistical processing was carried out using the SPSS 22 program.

The prognostic significance of the studied parameters (CAVI and R-AI) in relation to the probability of diagnosing BCA atherosclerosis was studied in univariate and multivariate logistic regression models followed by ROC analysis.

The construction of models of single-factor and multi-factor logistic regression, described by the formula:

,

where p is the probability of atherosclerosis of the brachiocephalic arteries according to ultrasound data;

х is an independent factor;

b ₀ , b ₁ , _, b _i – coefficients of the multifactorial mathematical model.

The cut-off threshold for the binary classification (presence/absence of BCA atherosclerosis according to ultrasound data) for the model was considered a probability of 0.5.

The ROC (receiver operating characteristic) curve was built for each tested factor (CAVI and R-AI), as well as for the predictive probability array determined using a multifactorial logical model, in order to assess the quality of the binary classification. ROC curves were built for each tested factor. The area under the ROC curve (AUC) was determined. The quality of the model by AUC was assessed as follows:

0.9-1.0 - excellent;

0.8-0.9 - very good;

0.7-0.8 - good;

0.6-0.7 - average;

0.5-0.6 - unsatisfactory.

Correlation analysis was carried out using Spearman's test. When using statistical procedures, p<0.05 was considered a sufficient level of significance.

At the first stage of the study, a logistic regression analysis was performed with the inclusion of such independent variables as age, CAVI, R-AI and the presence of an atherosclerotic lesion of the BCA as a dependent state variable.

The parameters of single-factor logistic regression models with the specified variables are presented in Table 1.

Table 1 - Parameters of one-factor logistic regression models

covariates Change in the proportion of correct classification from step 0 to step 1, % Change -2Log likelihood
from step 0 to step 1 Constant IN Exp(B) R R ² Nigel Kirk Hosmer-Lemeshev agreement criterion (p) Age 77.0-81.5 382.3-276.5 -7.37 0.15 1.16 0.0001 0.39 0.016 CAVI 77.0-79.8 382.3-305.5 -10.17 1.23 3.43 0.0001 0.29 0.65 R-AI 77.0-78.1 382.3-338.0 -6.08 5.20 181.38 0.0001 0.17 0.93

The results of one-way regression analysis from Table 1 showed that all three independent variables statistically significantly predict the probability of diagnosing BCA atherosclerosis according to duplex scanning data.

At the same time, despite the fact that the “age” variable showed the largest decrease in the -2Log likelihood value, the Hosmer-Lemeshev fit test (significance test of only p = 0.016) suggests that this three-parameter model does not adequately describe the actual data in contrast to the CAVI and R-AI variables. Therefore, in further studies, only two parameters were taken into account: CAVI and R-AI.

The inclusion of arterial stiffness parameters CAVI and R-AI in a multivariate logistic regression model (Forward LR method) made it possible to obtain an equation with two statistically significant independent variables (Table 2), which makes it possible to predict the probability of the presence of atherosclerosis in the BCA during duplex scanning.

Table 2 - Parameters of the multivariate logistic regression model

covariates Change in the proportion of correct classification from step 0 to step 1, % Change -2Log likelihood
from step 0 to step 1 Constant IN Exp(B) R R ² Nigel Kirk Hosmer-Lemeshev agreement test (p) CAVI 77.0- 81.3 382.3 - 294.3 -11.82 1.045 2.85 0.0001 0.33 0.78 R-AI 3.21 24.82 0.001

The data in Table 2 shows that the proportion of correct classification as a whole for the multivariate model was 81.3%, and the R ² Nigelkirk coefficient was 0.33. The Hosmer-Lemeshev criterion (p=0.78) allows us to say that the resulting model adequately describes the actual data.

The two-way logistic regression equation for the probability of having BCA atherosclerosis based on the CAVI and R-AI values is as follows:

p=1/1+e ^{-(-11.82+1.045xCAVI+3.21xR-AI)}

The results of ROC analysis for CAVI and R-AI stiffness indices, as well as the predicted probability based on a multivariate logistic model and BCA atherosclerotic lesions are presented in Table 3 and Figure 1 (Fig. 1 shows ROC curves for CAVI, R-AI, as well as the predicted probability based on a multivariate logistic model and the presence of an atherosclerotic lesion of the BCA according to duplex scanning data).

Table 3 - Results of ROC analysis of the parameters of the regression model

Validation Result Variables Area under the curve (AUC) Standard error ^* p ^** Asymptotic 95% confidence interval Bottom line Upper bound CAVI 0.803 0.027 0.0001 0.751 0.855 R-AI 0.736 0.031 0.0001 0.676 0.796 Predicted probability based on a two-factor model 0.817 0.026 0.0001 0.767 0.868

*According to the non-parametric assumption;

**Null hypothesis: = actual area = 0.5.

The ROC data showed a very good predictive power of the CAVI test (AUC=0.803) and a good predictive power of the R-AI test (AUC=0.736) in relation to the probability of having BCA atherosclerosis on duplex scanning. When both criteria of arterial stiffness were included in the logistic regression model with the calculation of the predictive probability of the presence of atherosclerosis, it was possible to obtain AUC = 0.817 (for the predicted probability and the actual presence of atherosclerosis), which indicates a very good predictive quality of the two-factor model.

Analysis of Figure 1 showed that, according to the ROC analysis matrix, the cut-off point value (cut-off point for any diagnostic indicator) for CAVI in relation to the atherosclerotic lesion of the BCA in the patient is 7.45 with a sensitivity of 62% and a specificity of 81%; for R-AI this is 0.98 with a sensitivity of 52% and a specificity of 78%.

The resulting logistic regression equation looks like this:

p=1/1+e ^{-(-11.82+1.045xCAVI+3.21xR-AI)}

Thus, the study demonstrated a statistically significant role of CAVI and R-AI in the diagnosis of BCA atherosclerosis.

The results of the study showed that the indicated indices of arterial stiffness make it possible to statistically significantly diagnose BCA atherosclerosis according to the data of volumetric sphygmography. The diagnostic significance of these criteria is not the same, but it allows with a fairly high accuracy of 81.3% to carry out the diagnosis of atherosclerotic lesions of the BCA when implementing the screening method. The inclusion of volumetric sphygmography in a periodic medical examination will ensure timely detection of carotid artery lesions in asymptomatic patients (especially young people) and will ensure a targeted selection of contingents for subsequent referral for BCA ultrasound.

Consider the implementation of the proposed method on specific examples.

Example 1. Patient S., aged 45, an employee of an oil company. During his examination, the following functional indicators were established:

CAVI=8.9; R-AI=1.3. To determine the probability of the presence or absence of atherosclerotic lesions of the brachiocephalic arteries in this patient, according to the proposed method, we substitute the value of these indicators into the formula:

p \u003d 1 / 1 + e ^{- (-11.82 + 1.045x8.9 + 3.21x1.3)} \u003d 0.84

According to the results of the calculation, the probability of having atherosclerosis of the brachiocephalic arteries is 0.84, i.e. higher than 0.5, which means that the patient is diagnosed with an atherosclerotic lesion of the BCA by the proposed method. Ultrasound of the BCA in this patient revealed atherosclerosis. This means that the diagnostics using the proposed method is performed correctly.

Example 2. Patient A., 30 years old, an employee of an oil company. During his examination, the following functional indicators were established:

CAVI=7.2; R-AI=0.97. To make a diagnosis of the presence or absence of atherosclerotic lesions of the brachiocephalic arteries in a given patient, according to the proposed method, we substitute the value of these indicators into the formula:

p \u003d 1 / 1 + e ^{- (-11.82 + 1.045x7.2 + 3.21x0.97)} \u003d 0.24

According to the results of the calculation, the probability of having atherosclerosis of the brachiocephalic arteries is 0.24, i.e. below the value of 0.5, which means that the proposed method in the patient is diagnosed with no atherosclerosis of the BCA. During the control on ultrasound of the BCA in this patient, atherosclerosis of the BCA was not detected. That is, the diagnosis using the proposed method is performed with sufficient accuracy.

Example 3. Patient I., aged 59, an employee of an oil company. During his examination, the following functional indicators were established:

CAVI=8.7; R-AI=0.86. To make a diagnosis of the presence or absence of atherosclerotic lesions of the brachiocephalic arteries in a given patient, according to the proposed method, we substitute the value of these indicators into the formula:

p \u003d 1 / 1 + e ^{- (-11.82 + 1.045x8.7 + 3.21x0.86)} \u003d 0.51

According to the results of the calculation, the probability of having atherosclerosis of the brachiocephalic arteries is 0.51, i.e. slightly above the value of 0.5, which means that the proposed method in the patient is diagnosed with the presence of atherosclerosis of the BCA. When performing control on ultrasound of the BCA, atherosclerosis of the BCA was detected in this patient. That is, the diagnosis using the proposed method is performed correctly.

Thus, the proposed method has the following advantages over the known ones:

- the proposed method is screening and easy to perform, does not require stress testing or other labor-intensive measurements, requires little time to perform, and can be used even by paramedical personnel.

- the claims include two stiffness parameters that independently affect the diagnosis of the presence/absence of BCA atherosclerosis, which allows more accurate diagnosis.

Claims (7)

A method for screening diagnosis of atherosclerosis of brachiocephalic arteries in young and middle-aged men, according to which the patient is examined using volumetric sphygmography with the determination of diagnostic criteria: cardio-ankle vascular index (CAVI) and augmentation index of the right brachial artery (R-AI), and diagnosis of atherosclerosis brachiocephalic arteries is carried out according to a mathematical formula using previously obtained criteria: p=1/1+e ^{-(-11.82+1.045xCAVI+3.21xR-AI)} where p is the probability of the presence or absence of atherosclerotic lesions of the brachiocephalic arteries; e is a mathematical constant equal to 2.72; CAVI - cardio-ankle vascular index; R-AI - augmentation index of the right brachial artery; moreover, at a p value equal to or more than 0.5, the patient is diagnosed with the presence of atherosclerosis of the brachiocephalic arteries, and at a p value of less than 0.5, the absence of atherosclerosis of the brachiocephalic arteries is diagnosed.