RU2245680C1 - Method for diagnosing the cases of cardiac ischemia disease - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method involves carrying out Doppler tissular echocardiography examination. Left ventricle myocardium segments movement characteristics are measured in time in each j-th segment. Regional myocardium productivity index I_j of the left ventricle is measured with formula containing isovolumic contraction time, isovolumic relaxation time and withdraw period duration being used. I_j values estimation is carried out in segments fed by single coronary artery branch with blood. Left ventricle regional myocardium productivity index value being not less than in two segments fed by single coronary artery branch with blood and equal to or greater than 0.8, cardiac ischemia disease is to be diagnosed.

EFFECT: simplified diagnosis method.

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Description

FIELD OF THE INVENTION

The invention relates to medicine, namely to cardiology, in particular to echocardiography (Echocardiography), and can be used to diagnose coronary heart disease (CHD).

State of the art

IHD is one of the most common diseases of the cardiovascular system in economically developed countries. The central role in the pathogenesis of coronary heart disease belongs to myocardial ischemia, which is a complex set of processes caused by an imbalance between the oxygen demand of the myocardium and its delivery through the coronary bed (Janashia P.Kh., Nazarenko V.A., Ikolenko S.A. Pharmacotherapy of cardiovascular diseases, - M .: Russian State Medical University, 1998, p. 78). Mortality from cardiovascular disease is still the leading cause of death in the working-age population (A. Okorokov, Diagnosis of diseases of internal organs. - M .: Medicine, 2002, p. 86). Therefore, early diagnosis is necessary for the timely treatment of coronary heart disease, which prevents the development of heart failure and disability of patients with a cardiological profile. In this regard, the urgent problem of developing and introducing into wide clinical practice new highly informative and at the same time simple methods to diagnose coronary heart disease in the early stages of its development.

Diagnosis of coronary heart disease is based on the identification of objective signs of the disease and, above all, myocardial ischemia. In clinical practice, various methods are used for this purpose: electrocardiography (ECG) and electrocardiographic monitoring, physical exercise tests, radionuclide studies, exercise echocardiography, coronary angiography and others.

Conducted a search in patent and specialized literature found various methods for the diagnosis of coronary heart disease.

RF patent No. 2197180 (2003, BIMP No. 3) describes a “Method for the diagnosis of latent coronary heart disease in patients with arterial hypertension” during a Doppler echocardiographic study at rest. If diastolic dysfunction of the left ventricle (LV) is detected by the spectrum of the transmitral diastolic flow in patients with arterial hypertension (AH) without LV hypertrophy, IHD is diagnosed. The disadvantage of this method is that it is not possible to use in patients with a normal level of blood pressure and LV hypertrophy.

RF Patent No. 2200951 (2003, BIMP No. 8) protected the “Method for the diagnosis of coronary heart disease” by double determination of the level of immunoreactive insulin (IRI) in the blood serum during a bicycle ergometry test (VEM), with the first blood sampling being performed on an empty stomach in the morning at rest, and the second at the threshold load power. With an increase in IRI by 50% of the initial value, latent coronary heart disease is diagnosed. The disadvantage of this method is the large list of contraindications for stress tests, invasiveness, the need for double blood sampling, which significantly lengthens the study time.

RF patent No. 2150880 (2000, BIMP No. 17) describes a “Method for the diagnosis of coronary heart disease” based on measuring the rate of confluent diastolic flow (G) during a stress test during transesophageal atrial stimulation (AES) at the junction of the mitral cusps valve and at a distance of 3 cm towards the apex (G1) of the left ventricle. Calculate the ratio G1 / G. With the obtained values of this ratio less than 0.8, IHD is diagnosed. The disadvantages of the method are the need to participate in the study of at least two doctors, the need to register an ECG in 12 standard leads throughout the test, the ability to stop the test until the maximum heart rate (HR) or obvious ischemic signs on the ECG, for example, at the request of the patient for subjective sensations.

There is a method of topical diagnosis of coronary heart disease by assessing the condition of the coronary arteries and the left ventricle of the heart by selective coronary cardiography (Rabkin I.Kh. Guide to angiography. - M .: Medicine, 1977, p. 59-75). The method consists in a contrast study of the coronary arteries and LV in the direct, lateral and oblique projections. The high cost, technical requirements, invasiveness, the need for highly qualified personnel today limits the use of this method, in addition, impaired perfusion at the level of small coronary arteries during coronary angiography is not visualized. (Chazov EI Diseases of the circulatory system. - M.: Medicine, 1997, p. 832).

The closest analogue of the claimed invention, taken as a prototype, is the "Method for the diagnosis of coronary heart disease" described in the patent of the Russian Federation No. 2182464 (2002, BIMP No. 14). The method consists in the diagnosis of coronary heart disease based on the assessment of the presence of ischemia by the nature of changes in the parameters of tissue velocities by conducting tissue doppler echocardiography (TD-Echocardiography) during stress echocardiography. The acceleration index is calculated as the ratio of the early tissue diastolic velocity to the acceleration time, measured from the beginning of the diastolic movement of the myocardium to the onset of the peak velocity of the early diastole. The retardation time calculated from the peak rate of early diastolic filling to diastasis is calculated. With a decrease in the acceleration and deceleration rates and with a change in the ratio of the early diastolic speed to the late diastolic speed from a value of more than 1 initially to a value of less than 1, IHD is diagnosed during the test.

The disadvantages of the prototype are the complexity of the method, its limited diagnostic capabilities associated with the need for physical activity, since the presence of a large number of contraindications for stress tests (NP) makes it impossible to use the method in all patients. In addition, the possibility of various kinds of complications during the NP - excessive hypertonic reaction, rhythm disturbances, provocation of angina pectoris up to myocardial infarction - limit its use in non-specialized medical institutions. In addition, NP has an increased complexity and significantly lengthens the study time, since during its conduct requires the participation of at least 2 doctors, as well as continuous monitoring of ECG and blood pressure.

The aim of the invention (its technical results) is to simplify the procedure for recognizing myocardial ischemia at the segmental level, the possibility of applying the method to all patients without limitation, as well as reducing the time of the study.

Disclosure of invention

This goal is achieved by measuring the temporal indicators of movement j of the LV myocardium segments recorded during TD-Echocardiography. As time indicators, the time of isovolumic contraction (t _ivcj ), the duration of the expulsion period (t _sj ), the time of isovolumic relaxation (t _ivrj ) are _measured . In each jth LV segment, the index of regional myocardial productivity (Ij) is calculated by the formula

Where

j is the segment number;

t _ivcj is the isovolumic contraction time;

t _ivrj is the time of isovolumic relaxation;

t _sj is the duration of the exile period.

With a value of And _j equal to or more than 0.8 in at least two LV segments supplied with one branch of the coronary artery, IHD is diagnosed. The method is illustrated using the drawing.

Brief Description of the Drawing

The drawing shows a spectrogram, which consists of a systolic wave “sj” and two diastolic waves “ej” and “aj”. The systolic wave has two peaks - “s ₁ j” and “S ₂ j”. The peak “s ₁ j” occurs during the period of isovolumic contraction, “s ₂ j” is the actual systolic contraction of the LV wall. Diastolic wave “ej” - corresponds to the peak of early diastolic filling in the spectrum of the transmitral flow, “aj” - corresponds to the peak of atrial filling. The duration of the systolic peak “s ₁ j” corresponds to the time of isovolumic contraction - t _{ivc j} , the duration of the systolic peak “s ₂ j” - corresponds to the length of the expulsion period - t _sj , and the interval between the end of the period of exile and the beginning of “ej” corresponds to the time of isovolumic relaxation - t _{ivr j} (Beresten N.F., Krutova T.V., Drobyazko O.A. et al. Possibilities of tissue doppleroechocardiography: literature review. Ultrasound. Volume 3, No. 4, 2002, p. 395).

The implementation of the method

The method is as follows.

An ultrasound examination of the heart in the patient’s position on the left side is performed on an Akuson Aspen ultrasound scanner (Siemens) using a variable frequency sensor of 2-3.5 MHz. Four-chamber and two-chamber apical sections of the LV are obtained from the apical access, which makes it possible to evaluate the myocardium in the areas of blood supply to all coronary arteries, taking into account the segmental division of the LV proposed by the American Association for Echocardiography (Mitkov V.V., Sandrikov V.A. Clinical Guide to Ultrasound Diagnostics. - M .: Vidar, 1998, 5 volume, p.143-144). TD-Echocardiography is carried out in a pulsed mode with the filter installed to receive low-frequency signals and minimizing the amplification of Doppler signals in the basal, middle and apical segments of the interventricular septum, lateral, lower and anterior LV walls.

The control volume of the tissue pulse-wave Doppler is sequentially located in the center of each of the j-investigated LV segments, observing the insonation angle, and the Doppler spectrum of wall motion is recorded. A spectrogram is displayed on the monitor screen (see drawing).

The temporal indicators of myocardial motion are measured: t _{ivc j} , t _sj , t _{ivr j} (ms). Then, successively in each j-th segment is calculated and _j LV by formula (1). Then, the values of And _{j are} estimated in the segments supplied with one branch of the coronary artery. If the value of And _j LV is equal to or more than 0.8 in at least two segments supplied with one branch of the coronary artery, ischemic heart disease is diagnosed.

The study is based on determining the local function of the left ventricular myocardium. The TD-EchoCG method allows you to obtain accurate quantitative information about the movement of the myocardium in the zone of interest during the cardiac cycle by fixing the direction, speed and time of the characteristics of the movement of heart tissue at a given point in two-dimensional space in real time. In coronary heart disease, insufficient oxygen supply to the myocardium leads to a deficiency of macroergic compounds, which in turn leads to a slowdown in the process of early diastolic LV relaxation and an increase in isovolumic relaxation time (Mazur N.A. Diastolic myocardial dysfunction. - M.: RMAPO, 2001, p. 47-49). The increase in the length of the period of isovolumic contraction, the shortening of the period of exile corresponds to severe obstructive damage to the coronary arteries and is observed in the case of a marked decrease in myocardial contractility against the background of its severe ischemic damage (Kubyshkin V.F. Cardiodynamic phase syndromes. - Kiev: "Health", 1982, p. 98). Thus, the determination of the regional myocardial productivity index values allows us to capture and record the entire spectrum of ischemic changes in the myocardium at various stages of the development of coronary heart disease.

The method is illustrated by clinical examples.

Example 1: Patient P., 42 years old, medical history 835/92, was admitted to the cardiology department Growing HMU with complaints of shortages of air, discomfort behind the sternum arising from physical exertion. He considers himself sick for two years, when he first noted the appearance of the above symptoms, and therefore was treated for osteochondrosis. Entered for examination and clarification of the diagnosis. The results of the instrumental examination: ECG - normal position of the electrical axis of the heart. Sinus rhythm, heart rate 72 beats. in min, LV myocardial hypertrophy. Cardiac echocardiography (EchoCG) - moderate LV myocardial hypertrophy, LV systolic function is not impaired. The aorta is sclerosed, the root is dilated, valvular dysfunction and pulmonary hypertension have not been identified.

In the TD-Echocardiography mode, the patient was tested by the proposed method and calculated And _j . The results are presented in table 1. The index values were more than 0.8 in seven segments (the middle and apical segments of the MJP, the apical lateral, median and apical lower, basal, median and apical anterior segments) of the LV supplied with the left coronary artery (LCA), and namely, the anterior interventricular branch (LAD), and in three segments (basal MJP, basal and middle lower segments) of the LV, which are supplied with the right coronary artery (PCA). The patient was diagnosed with coronary heart disease. Coronary angiography (CG) was performed to confirm the patient. Results of CG: LCA - stenosis of the LAD in more than 80% in the proximal third and 40% in the middle third, PKA - stenosis of 70% in the proximal third. Coronary angiography confirmed the diagnosis made to the patient according to the claimed method. Surgical treatment is recommended for the patient.

Table 1 j Segment name Time interval, ms. And _j t _ivcj t _ivrj t _sj 1 Basal MJP 120 140 240 1,08 7 Basal lower 110 140 260 0.96 8 Middle bottom 90 140 200 1.15 2 Median MJP 80 130 250 0.84 3 Apical MJP 100 150 250 0.96 6 Apical lateral 100 130 260 0.88 nine Apical lower 120 150 270 1,0 10 Basal anterior 70 160 270 0.85 eleven Middle front 90 160 260 0.96 12 Apical anterior 120 140 230 1.13 4 Basal lateral 70 90 280 0.57 5 Median lateral 70 90 240 0.66

Example 2: Patient G., 53 years old, medical history No. 6239/646, was admitted to the cardiology department. The growth of HMU with complaints of discomfort behind the sternum during physical exertion. Arterial hypertension for 5 years. Constantly not treated. Periodically took Trirezid K. Entered for examination and clarification of the diagnosis. Instrumental research data: ECG - sinus rhythm, heart rate 68 beats. in minutes Normal position of the electrical axis of the heart. Violation of the processes of repolarization of the anterior septum. Echocardiography - heart cavities are not expanded, myocardial hypertrophy is not. Global contractility and LV systolic function are not impaired. Initial manifestations of LV diastolic dysfunction type 1. Compaction of the aorta. Mitral regurgitation of 1 degree. There are no zones of violation of local contractility at rest.

In the TD-Echocardiography mode, the patient was tested by the proposed method and calculated And _j . The results are presented in table 2. The index values were more than 0.8 in seven segments (the middle and apical segments of the MJP, the apical lateral, median and apical lower, basal, median and apical anterior segments) of the LV supplied with the left coronary artery (LCA), and it is the anterior interventricular branch (LAD). The patient was diagnosed with coronary heart disease.

table 2 j Segment name Time interval, ms. And _j t _ivcj t _ivrj t _sj 2 Median MJP 90 120 250 0.84 3 Apical MJP 90 140 240 0.96 6 Apical lateral 100 150 260 0.96 nine Apical lower 100 150 240 0.99 10 Basal anterior 110 140 260 0.96 eleven Middle front 120 140 230 1.13 12 Apical anterior 90 120 230 0.91 1 Basal MJP fifty 80 200 0.65 7 Basal lower 90 70 240 0.66 8 Middle bottom 80 60 230 0.6 4 Basal lateral 60 120 280 0.64 5 Median lateral 70 110 300 0.6

To confirm the patient was conducted CG. The result of the CG: stenosis of the LAD in more than 90% in the proximal third. Coronary angiography confirmed the diagnosis made to the patient according to the claimed method. Surgical treatment is recommended for the patient.

To confirm the informational content of the proposed method, we examined 45 patients (including 5 patients with unstable angina, 1 patient with polytopic ventricular extrasystole, 6 patients with severe arterial hypertension), who were in the cardiac surgery department of the clinic Growth HMU, which, on the basis of a general clinical examination, was delivered diagnosis of ischemic heart disease. To confirm inadequate blood flow in the coronary arteries, the entire patient underwent coronary ventriculography according to Seldinger. Then, these patients underwent TD-Echocardiography according to the proposed method on an Akuson Aspen ultrasound scanner (Siemens) using a variable frequency sensor of 2-3.5 MHz. The temporal indicators of myocardial movement in the basal, middle and apical segments of the interventricular septum, lateral, lower and anterior LV walls were determined. In each jth segment, And _{j was} calculated by the formula (1). The values of And _j in segments with coronary blood flow deficiency (coronarographically confirmed stenosis of 50% or more) were 0.8 or more, while the values varied: t _{ivc j} from 60 to 140 ms, t _{ivr j} from 70 to 160 ms, t _sj 200 to 280 ms The Ij value in the segments without coronary blood flow deficiency ranged from 0.5 to 0.68, while the values varied: t _ivcj from 30 to 50 ms, t _ivrj from 70 to 90 ms, t _sj from 270 to 340 ms. The duration of the study of one patient by the claimed method averaged 35 ± 10 minutes

We conducted a retrospective analysis of 10 case histories of patients examined according to the prototype, that is, using physical activity. The average study duration was 60 ± 5 min.

Thus, in comparison with the prototype of the claimed method has the following advantages:

1. The procedure for recognizing LV myocardial ischemia is simplified at the segmental level.

2. Reduced time and labor costs of the study.

3. The method can be applied to all patients without limiting contraindications.

Claims (1)

A method for the diagnosis of coronary heart disease (CHD) by measuring the temporal indicators of the movements of the left ventricular myocardium (LV) segments by tissue doppler echocardiography (TD-Echocardiography), characterized in that isovolumic contraction time (t _ivcj ), isovolumic relaxation time (t _ivrj ) are _measured , the duration of the expulsion period (t _sj ), then in each estimated jth LV segment the LV myocardial regional productivity index (AND _j ) is calculated by the formula:

where j is the segment number, t _ivcj is the isovolumic contraction time, t _ivrj - isovolumic relaxation time, t _sj - the duration of the expulsion period, then assess the values of And _j in the segments supplied with one branch of the coronary artery, and when the index of regional productivity of the LV myocardium is not less than two, supplied with one branch of the coronary artery, segments equal to or more than 0.8 diagnosed with coronary heart disease.