RU2356492C1 - Absent coronary artery involvement diagnostic method in suspected coronary heart disease and pseudoischemic electrocardiogram changes - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: patients of CHD are examined for graduated physical activity (GPA). The absent coronary artery involvement is derived from original mathematical formulas with using GPA duration, available maximum heart rate in GPA examination, as well as angina and ejection fraction intensities.

EFFECT: method allows detecting involvement of one coronary artery and more than 2 coronary arteries, the absence of hemodynamically important involvements of coronary arteries by low-price and noninvasive method without coronary angiography required.

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Description

Coronary heart disease (CHD) remains the main cause of mortality in all developed countries, including Russia. In this case, both the diagnosis of coronary heart disease and the assessment of the severity of the course and prognosis of this disease are important. The severity of CHD is closely correlated with the degree of damage to the coronary arteries. At the same time, often heartless pains (cardialgia) often resemble angina pectoris, the main manifestation of chronic CHD. Moreover, in some cases, the so-called "pseudo-ischemic" changes appear on the ECG. All this can lead to a non-existent diagnosis of coronary heart disease, the appointment of unnecessary treatment, etc.

For the diagnosis of coronary heart disease, it is known to use samples with dosed physical activity (PDPN) (Aronov D.M. et al. Functional tests in cardiology, Cardiology, 1995, No. 12, pp. 83-93). Using such samples, it is possible not only to diagnose coronary heart disease, but also to determine the severity of its course (RF patent No. 2272559, 03/27/2006).

However, there is still no complete clarity on the question of which of the indicators recorded in the process of conducting these tests have the greatest significance, there is also no unambiguous general interpretation of the results of PDPN, which can lead to an incorrect assessment of the severity of coronary heart disease in a particular patient.

A method is also known that allows, according to the results of PFD on the treadmill, to divide patients with coronary heart disease into groups of high, medium and low risk using the so-called Duke index. This technique takes into account the duration of physical activity, the value of the maximum displacement of the ST segment during the test, and the severity of angina (Marc D. Et. Al., 1991).

A significant drawback of the Duke index is that it well reflects the severity of coronary heart disease in patients with a severe course of the disease, and in patients with a milder course of coronary artery disease and in people without coronary artery disease, it is less informative, since ST segment depression in PDPN is not always recorded even in patients with severe ischemic heart disease. When using the Duke index, you can get underestimated indicators that exaggerate the severity of the disease associated with pseudo-ischemic depression of the ST segment.

In addition, the methods listed above, which make it possible to assess the severity of coronary heart disease using PDPH, do not allow to identify the number of affected coronary arteries based on non-invasive research methods.

To assess coronary artery damage and the severity of coronary heart disease, selective coronary angiography is used (Diagnosis and treatment of stable angina pectoris. Russian recommendations. VNOK, M., 2004, pp. 3-28). The method of angiography is complex, invasive, when performing the study, the risk of developing complications is high and, in addition, the method is not publicly available. However, this particular method is closest to the claimed

The present invention is aimed not only at the possibility of detecting the severity of ischemic lesions, but also at identifying with a high degree of probability the number of coronary arteries affected by the atherosclerotic process. Moreover, the proposed method is non-invasive, simple and cheap.

The invention is as follows:

The following studies were carried out for patients with coronary heart disease (318 people):

1. History taking, identification of risk factors for coronary heart disease.

2. Standard survey for the detection of angina pectoris.

3. Removal of an ECG at rest.

4. Test with dosed physical activity on the treadmill.

5. Echocardiography.

Samples with dosed physical activity (DFN) were performed on a treadmill, according to the protocol developed in the department of preventive pharmacology and used in the SRRC for scientific and practical activities. The load test protocol is presented in table 1.

Table 1.
Treadmill physical exercise test protocol used at GNITsPM Stage Treadmill Speed Treadmill angle Stage duration one 3 km / h 0% 3 min 2 4 km / h four% 3 min 3 4 km / h 8% 3 min four 4 km / h 12% 3 min 5 4 km / h 16% 3 min 6 5 km / h 16% 3 min 7 5 km / h twenty% 3 min 8 6 km / h twenty% 3 min 9 6 km / h 24% 3 min

The criterion for termination of the exercise test was the achievement of submaximal heart rate (75% of the maximum for a given age and gender) or the achievement of an attack of moderate intensity angina, as well as generally accepted signs requiring the cessation of physical activity. The intensity of pain with a submaximal load of angina was evaluated in points (BFN) in accordance with the scale

0 - lack of pain;

1 - clearly felt pain that does not require cessation of physical activity;

2 - pain, requiring, as a rule, termination of the load or reduce its pace;

3 - severe pain requiring the use of nitroglycerin.

In addition, echocardiographic examinations were performed in B and M modes, Doppler echocardiography on an Acuson-128Xp ultrasound system (Siemens) with an electronic vector sensor (frequency of the ultrasonic oscillation generator 2.5-3.5 MHz). Visualization of the heart structures was carried out from the parasternal and apical accesses along the long and short axes of the heart in the patient's position on the left side. Under the control of a 2-dimensional image, echocardiography was performed in M-mode with simultaneous registration of a standard ECG lead at a speed of 100 mm / s. The sizes of the left and right atria were determined according to generally accepted methods. The calculations were carried out in at least three positions.

The following parameters were determined: systolic and diastolic sizes of the left ventricle (KSR and KDR, cm), the thickness of the interventricular septum and the posterior wall of the left ventricle (MFZD and ZSD, cm). The final diastolic and final systolic volumes of the left ventricle (LV) (BWW and CSR, ml), stroke volume (l / min),% anteroposterior shortening of the LV into the systole (% Δ S,%), as well as the LV ejection fraction (EF, %).

The ischemia index (II) is calculated by the formula

AI = (T + HR max / 100-5 * WB) + 366/604 * PV,

where T is the duration of the test with physical activity (FN) (min);

Heart rate - the maximum heart rate achieved during the sample with fn (beats / min);

WB - the severity of pain in points (0 - the absence of pain; 1 - clearly felt pain that does not require cessation of physical activity; 2 - pain requiring cessation of exercise) PV - ejection fraction (in percent).

They make a diagnosis by calculating the prognostic index of PI according to the formula:

PI = 0.02 * B-3.79 * P + 0.04 * (P-1) * B + 1.02 * IM + 1.13 * WB2 +

1.8 * FC2 + 2.09 * FCZ + 1.42 * IPN + 0.42 * IPU,

where B is the age (in years);

P - gender (1 - male, 2 - female);

MI - myocardial infarction (0 - no, 1 - yes);

VB2 - the severity of pain during exercise, estimated at 2 points;

FC2 - angina pectoris of the 2nd functional class in points (0 - no, 1 - yes);

ФК3 - angina pectoris of the 3rd functional class of the class in points (0 - no, 1 - yes);

IIT - indicator variables of belonging to the low values of the AI index (if AI <= 31.5, then IIT = 1; in other cases, IIT = 0);

IPU - indicator variables of belonging to moderate values of the AI index (if 31.5 <AI <= 41.6, then IPU = 1, in other cases, IPU = 0;); and with PI <= - 1.25, it is believed that the patient has no hemodynamically significant lesions of any of the coronary vessels

The invention is illustrated by the following examples:

Example 1

Patient T., 49 years old. Complaints of pain in the left half of the chest, prolonged, occurring both during physical activity and at rest. Sometimes resorting to taking nitroglycerin (atypical angina pectoris). HELL is usually normal, but rises to 150/90 mm Hg are sometimes recorded. Smooth or negative T waves in the left chest leads periodically appear on the ECG. The clinic is diagnosed with Coronary Heart Disease, angina pectoris 2 functional class. Treatment with antianginal drugs (nitrates) was prescribed, which did not give an effect, while causing a headache. A test was carried out with a load on the treadmill. Sample duration 14 min. The reason for the termination of the test is fatigue and the achievement of a submaximal heart rate of 150 per minute. Angina pectoris during the test is not fixed. On the ECG in leads III, aVF, V4, V5, depression of the ST segment in 2 mm of the intermediate form (between horizontal and oblique) was recorded.

Echocardiography revealed no significant deviations from the norm. The ejection fraction is 65%.

Index calculation: AI = (14 + 115 / 100-5 * 0) + 0.6 * 65 = 54.9, i.e. IIT = 0, IPU = 1.

PI = 0.02 * 49-3.79 * 2 + 0.04 * 1 * 49 + 1.02 * 0 + 1.13 * 2 + 1.8 * 0 + 2.09 * 0 + 1.42 * 0 + 0.42 * 1 = -4.14.

Conclusion - the absence of a significant lesion of the coronary arteries can be suspected.

With coronary angiography, stenotic changes in the coronary arteries were not detected.

The Duke index, calculated according to the results of the same stress test, was 4, which falls into the zone of moderate risk.

The examination allowed to make a diagnosis of coronary disease. After 3 years, the patient was alive; no complications from the cardiovascular system occurred during this time.

Thus, in this case, the use of the proposed index, in contrast to the Duke index, which assigned the patient to a moderate risk group, made it possible to assess the patient's prognosis as favorable. Despite feeling unwell, the presence of “pseudo-ischemic” signs on the ECG, the diagnosis of coronary heart disease was withdrawn, unnecessary drug treatment was canceled, life prognosis was assessed as favorable. Further observation confirmed the correctness of the conclusions made (for 3 years the patient did not experience any cardiovascular complications).

Example 2

Patient K., 53 years old. Complained of pain behind the sternum during fast walking, climbing stairs, forcing to stop or reduce the pace of walking (typical angina pectoris, class 2). Does not use nitroglycerin. 3 years ago, among complete health, he suffered a myocardial infarction of anterior localization. HELL is normal.

On examination: satisfactory condition. There are no visible edema. On an ECG taken at rest, cicatricial changes in the anterior localization. With echocardiography - a decrease in local and global contractility of the left ventricle, ejection fraction - 38%.

In the test with a load on the treadmill - performed a load lasting 6 minutes. The reason for the termination of the load is the development of a typical attack of angina pectoris (2 points), while no ST segment changes were recorded in any of the 12 ECG leads.

Maximum heart rate during the test - 115 per min.

Index calculation: AI = (6 + 115 / 100-5 * 2) + 366/604 * 38 = 20.35, i.e. IPP = 1, IPU = 0.

PI = 0.02 * 53-3.79 * 1 + 0.04 * 0 * 53 + 1.02 * 1 + 1.13 * 2 + 1.8 * 1 + 2.09 * 0 + 1.42 * 1 + 0.42 * 0 = 3.89.

Conclusion - damage to two or more coronary arteries can be suspected. The Duke index calculated based on the results of the same test was equal to - 2 (moderate risk).

Thus, with relatively good health, the absence of ECG signs of myocardial ischemia, the use of the proposed index according to the results of a test with a load revealed a high risk of complications. The traditional Duke index indicated only moderate risk. Coronary angiography performed at the same time revealed stenotic changes (stenosis of more than 75%) of all three major coronary arteries. Aorto-coronary bypass surgery (which the patient refused) was recommended. Prescribed drug therapy. 2 years after the initial examination, the patient died suddenly.

Thus, the proposed index makes it possible to assess the absence of coronary artery lesions, in particular in patients with the presence of “pseudo-ischemic” signs on the ECG, without using the expensive invasive method of selective coronarography, to clarify drug treatment and assess the prognosis of life.

Claims (1)

A method for diagnosing the absence of damage to the coronary arteries with suspected coronary artery disease, characterized in that they perform tests with dosed physical activity (DF), conduct an echocardiographic study, calculate the ejection fraction, calculate the integral index of ischemia (II) by the formula
AI = (T + HR max / 100-5 · WB) + 366/604 · PV,
where T is the duration of the test with physical activity (FN), min;
Heart rate max - achieved maximum heart rate during the sample with fn, beats / min;
WB - the severity of pain in points (0/1/2) with FN;
PV - ejection fraction,%,
calculate the prognostic index PI according to the formula
PI = 0.02 · B-3.79 · P + 0.04 · (P-1) · B + 1.02 · IM + 1.13 · WB2 +
1.8 · FC2 + 2.09 · FC3 + 1.42 · IPN + 0.42 · IPU,
where B is the age (in years);
P - gender (1 - male, 2 - female);
MI - myocardial infarction (0 - no, 1 - yes);
VB2 - the severity of pain during exercise, estimated at 2 points;
FC2 - angina pectoris of the 2nd functional class in points (0 - no, 1 yes);
ФК3 - angina pectoris of the 3rd functional class in points (0 - no, 1 yes);
IIT - indicator variables of belonging to the low values of the AI index (if AI <= 31.5, then IIT = 1; in other cases, IIT = 0);
IPU - indicator variables of belonging to moderate values of the AI index (if 31.5 <II <= 41.6, then IPU = 1, in other cases, IPU = 0); and with PI <= - 1.25, the absence of hemodynamically significant lesions of the coronary vessels is diagnosed in patients with suspected coronary artery disease.