RU2312585C1 - Method for detecting the risk of ischemic cardiac disease complications - Google Patents

Abstract

FIELD: medicine, cardiology.

SUBSTANCE: in patients with ischemic cardiac disease (ICD) it is necessary to carry out tests with dosed physical loading (DPL), echocardiographic studying and estimation of ejection fraction. One should calculate integral index (II) by the following formula: II=(T+HRmax/100-5*SD)+0.605*EF, where T - the duration of DPL (min); HRmax - achieved maximal HR at DPL tests being (strokes/min); SD - stenocardia degree in points (0/1/2); EF - ejection fraction (percentage). At II value <=31, 32-36, 37-42, 43-50 the risk of ICD complications should be evaluated, correspondingly, as high, moderately high, moderate and low. The innovation enables to stratify ICD patients according to the degree of coronary arteries' lesions and evaluate the risk of complications more objectively.

EFFECT: higher accuracy of detection.

2 ex, 2 tbl

Description

Coronary heart disease (CHD) takes a leading place in the structure of mortality in all developed countries. In the United States, for example, about 13.5 million people suffer from coronary heart disease, and it is coronary heart disease that causes death in more than one fifth of all deaths. In Russia, among men 35-64 years old, mortality from coronary heart disease is 56.6% of all deaths from cardiovascular diseases, among women of the same age this figure is 40.4%.

Moreover, the presence of angina pectoris as a syndrome indicates an increased risk of death. It is known that in individuals complaining of chest pain not related to physical activity, i.e. on cardialgia, mortality is more than 3 times less than in patients with angina pectoris (Shalnova S.A., Maksimov A.V., Kapustina G.S. et al. Prognostic significance of various variants of chest pain in men aged 40-59 Ter. Arkh., 1988, No. 1, 30-34).

However, in some patients with coronary heart disease suffering from angina pectoris, the disease has been stable for many years and does not end with any serious complications.

The prognosis of chronic coronary heart disease is primarily determined by the prevalence of stenotic changes in the coronary arteries and the degree of dysfunction of the left ventricle. So, it is shown that the annual mortality of patients with coronary artery disease with a lesion of one coronary artery, according to coronary angiography, is 2%, with a lesion of 2 coronary arteries - 7%, with a lesion of 3 coronary arteries - 11% (Reeves T., Oberman A., Jones W. Natural history of angina pectoris. Am. J. Cardiol. 1974; 33: 423-430).

J. Puma et al. showed that the prognosis of life for patients with isolated proximal stenosis of the left CA is quite favorable if this stenosis formed long ago (chronic occlusion) (Puma JA, Sketch MH, Tcheng JE Et al. The natural history of single-vessel chronic coronary occlusion: A 25-year experience. Am. J. Cardiol. 1997; 133: 393-399) 195]. The 15-year survival rate in patients with chronic proximal occlusion of the left SC was, according to this study, about 70%. In almost all of these patients, angina pectoris was detected. However, the angiography method is complex, invasive, when performing the study, the risk of developing complications is high and, in addition, the method is not publicly available.

Given the low availability of coronary angiography, in Russia the question of how a practical doctor can assess the risk of IHD complications in a particular patient is extremely relevant.

For the diagnosis of coronary heart disease, it is well 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 artery disease, but also to determine the severity of its course (RF patent No. 2272559, 03/27/2006), as well as to predict the course of the disease (RF patent No. 2220651, 01/10/2004).

Since coronary angiography is the most informative method that reflects the severity of changes in the coronary arteries and the severity of coronary artery disease, the results of stress tests were primarily compared with it (Lupanov V.P., Chotgaev Kh.Kh., Evstifeeva S.E., Deev A.D. et al. Clinical course of the disease and prognosis in patients with coronary heart disease with stable angina pectoris due to stenosing coronary atherosclerosis (data from a 20-year follow-up), Ter. Arch., 2002, No. 9, 13-20).

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

Closest to the claimed invention is a method that allows according to the results of PDPN on 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 values of 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 not always informative because ST segment depression in PDPN is not always recorded even in patients with severe ischemic heart disease. In addition, 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.

The invention is as follows.

The following studies were carried out for patients with coronary heart disease (259 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.

6. Coronaroangiography.

Some patients also had daily (Holter) ECG monitoring.

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 stress test was the achievement of submaximal heart rate (75% of the maximum for a given age and gender) or the achievement of an average intensity angina attack (2 points), as well as generally accepted signs requiring the termination of physical activity.

Prior to the test, patients were introduced to the scale for assessing the intensity of angina pectoris in points [157].

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.

For each sample, the duration of the DPF sample (min) was calculated, the maximum heart rate achieved with the DPF sample (strokes / min), the severity of angina in points (0/1/2). 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), thickness of the interventricular septum and the posterior wall of the left ventricle (MZhPD 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, %).

Calculated indicator integral index GNITsPM

AI = (T + HRmax / 100-5 · BC) + 0.605 · PV,

where T is the duration (min) DFN;

Heart rate - the maximum heart rate achieved during the DPF test (beats / min);

BC - the severity of angina in points (0/1/2);

PV - ejection fraction (in percent).

Quintiles of the indicator according to GNITsPM:

≤31, -32-36, -37-42, -43-50, -≥51

are considered to be groups of high, moderately high, moderate, low risk and a group of relative norm.

The invention is illustrated by the following examples.

Example 1

Patient K., 53 years old. Complained of pain behind the sternum during fast walking, climbing stairs, forcing to stop or slow down 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: 6 + 115 / 100-5 · 2 + 38 · 0.605 = 20.2 (high risk).

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 (in contrast to the Duke index) made it possible to objectively assess the prognosis of the patient's life. Despite the relatively satisfactory condition at the time of the examination, the index indicated a high risk of complications, long-term follow-up fully confirmed this fact.

Example 2

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 up 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%.

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

Index calculation: 14 + 150 / 100-5 · 0 + 65 · 0.605 = 54.8 (relative norm).

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 made it possible to remove the diagnosis of coronary heart disease and abandon the active drug treatment. The values of the proposed index, calculated on the basis of the test with physical activity, indicated a favorable prognosis of the patient's life (relative norm). 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 prognosis of the patient's life 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).

Statistics

All observed patients according to the results of the test with physical activity were divided into 5 subgroups depending on the values of the proposed index: less than or equal to 31 (average 25.4) - 36 people, 32-36 (average 34.0) - 37 people, 37-42 (average 38.5) - 37 people, 43-50 (average 45.5) - 37 people, more than or equal to 51 (average 55.7) - 37 people. These subgroups were designated respectively as subgroups of high risk, moderate high risk, moderate risk, low risk and relative norm.

When observing patients (period from 2 to 3 years) in these subgroups, the number of endpoints (any cardiovascular complications) was 18, 16, 15, 10, and 6, respectively, in%, this was 50.0, 43.2, respectively , 40.5, 27.0, 16.2. If the subgroup of the relative norm is taken as 1, then the probability of complications, standardized by age and gender, is 4.9 for the high-risk subgroup, 3.6 for the moderate-risk subgroup, 3.7 for the moderate-risk subgroup, and low-risk for the low-risk subgroup 1.8.

Table Subgroups High risk Moderately High Risk Moderate risk Low risk Relative rate Index quintiles ≤31 32-36 37-42 43-50 ≥51 Number of patients 36 37 37 37 37 The number of complications during the observation eighteen 16 fifteen 10 6 The complication rate in% 50,0 43,2 40.5 27.0 16,2 Relative risk of complications 4.9 3.6 3,7 1.8 1,0

The present invention provides a new integral index for dividing IHD patients into risk groups, which takes into account the values of several indicators of exercise tolerance and signs of myocardial ischemia, including the maximum heart rate achieved during PDPN, and also taking into account the ejection fraction. This index allows not only to stratify patients with angina pectoris by the severity of coronary artery damage, but also to determine the likelihood of a risk of IHD complications.

Claims (1)

A method for determining the risk of coronary heart disease complications, including conducting tests with dosed physical activity (DF) and the use of an integral index (II), characterized in that they additionally conduct an echocardiographic study, calculate the ejection fraction, and the AI is calculated by the formula: AI = (T + HRmax / 100-5 · BC) + 0.605 · PV, where T is the duration (min) DFN; Heart rate max - achieved maximum heart rate during the DPF test (beats / min); BC - the severity of angina in points (0/1/2); PV - ejection fraction (in percent), and with II values of 31, 32-36, 37-42, 43-50, the risk of coronary heart disease complications is assessed as high, moderately high, moderate and low, respectively.