Coronary heart disease: general information

Ischemic heart disease (IHD) is a myocardial lesion caused by impaired coronary blood flow. A synonym for the term "ischemic heart disease" is the term "coronary heart disease". Coronary artery lesions may be of organic or functional origin. Organic lesions are atherosclerosis of the coronary arteries, functional factors are spasm, transient platelet aggregation and thrombosis. Atherosclerotic stenosis of the coronary arteries is detected in approximately 95% of patients with IHD. Only 5% of patients have normal or slightly altered coronary arteries.

Cases of myocardial ischemia due to coronary blood flow disorders of other etiologies (abnormalities in the development of coronary arteries, coronary artery disease, aortic stenosis, relative coronary insufficiency with myocardial hypertrophy) are not related to coronary heart disease and are considered within the framework of the corresponding diseases (“ischemia without coronary heart disease”).

Ischemia is insufficient blood supply. Myocardial ischemia occurs when the myocardium's need for oxygen exceeds the capacity to deliver it through the coronary arteries. Therefore, the cause of ischemia may be either an increase in the myocardium's need for oxygen (against the background of a decrease in the ability of the coronary arteries to increase coronary blood flow - a decrease in the coronary reserve), or a primary decrease in coronary blood flow.

Normally, with an increase in the myocardium's need for oxygen, the coronary arteries and arterioles expand with an increase in coronary blood flow by 5-6 times (coronary reserve). With stenosis of the coronary arteries, the coronary reserve decreases.

The main cause of sudden reduction of coronary blood flow is coronary artery spasm. Many patients with coronary artery disease have a combination of atherosclerotic lesions and a tendency to coronary artery spasm. Additional reduction of coronary blood flow is caused by platelet aggregation and coronary artery thrombosis.

Coronary heart disease, most often associated with the atherosclerotic process, involves deterioration of blood flow through the coronary arteries. Clinical manifestations of coronary heart disease (CHD) include silent ischemia, angina, acute coronary syndrome (unstable angina, myocardial infarction) and sudden cardiac death. Diagnosis is based on characteristic symptoms, ECG, stress tests and sometimes (coronary angiography). Prevention involves changing correctable (modifiable) risk factors (such as hypercholesterolemia, physical inactivity, smoking). Treatment includes the administration of drugs and procedures aimed at reducing ischemia and restoring or improving coronary blood flow.

In the United States, ischemic heart disease is the leading cause of death in both sexes (one-third of all deaths). Mortality among Caucasian men is about 1 in 10,000 in the 25- to 34-year-old age group and almost 1 in 100 in the 55- to 64-year-old age group. Mortality among Caucasian men aged 35 to 44 years is 6.1 times higher than among Caucasian women of the same age. For unknown reasons, the sex difference is less pronounced among other races.

Mortality among women increases after menopause and by age 75 is equal to or even higher than that of men.

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Clinical forms of ischemic heart disease

There are 3 main clinical forms of coronary heart disease:

1. Angina pectoris

• Angina pectoris
• Spontaneous angina (rest angina)
• Unstable angina

2. Myocardial infarction

• Q-wave myocardial infarction
• Non-Q wave myocardial infarction

3. Post-infarction cardiosclerosis

The main complications of coronary heart disease:

1. Sudden coronary death
2. Heart rhythm disturbance
3. Heart failure

Before an accurate diagnosis is established, unstable angina and myocardial infarction are combined under the term "acute coronary syndrome". In addition to the listed clinical forms of coronary heart disease, there is the so-called "painless myocardial ischemia" ("silent" ischemia).

Among all patients with coronary heart disease, two main groups can be distinguished (two extreme variants of the clinical course of coronary heart disease):

1. patients who suddenly develop acute complications of coronary heart disease - acute coronary syndromes: unstable angina, myocardial infarction, sudden death;
2. patients with gradual progression of angina pectoris.

In the first case, the causes are rupture of an atherosclerotic plaque, coronary artery spasm, and acute thrombotic occlusion. Small ("hemodynamically insignificant") plaques that stenose less than 50% of the lumen of the coronary artery and do not cause angina pectoris are more likely to rupture. These are plaques with an increased lipid content and a thin capsule (the so-called "vulnerable", "unstable" plaques).

In the second case, there is a gradual progression of stenosis with the formation of a "hemodynamically significant" plaque, stenotic over 50% of the lumen of the coronary artery. In this case, "stable" plaques with a dense capsule and lower lipid content are formed. Such stable plaques are less prone to rupture and are the cause of stable angina.

Thus, to a certain extent, there has been a change in the ideas about the clinical significance of the degree of stenosis of the coronary arteries - despite the fact that clinical manifestations of myocardial ischemia occur with more pronounced stenosis, acute coronary syndromes are more often observed with minor stenosis, due to the rupture of small, but "vulnerable" atherosclerotic plaques. Unfortunately, the first manifestation of coronary heart disease is often acute coronary syndromes (in more than 60% of patients).

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Prevention of ischemic heart disease

Prevention of coronary heart disease involves eliminating risk factors for atherosclerosis: stopping smoking, reducing excess body weight, healthy eating, rational physical activity, normalizing the lipid profile of blood serum (especially the use of HMG-CoA reductase inhibitors - statins), controlling arterial hypertension and diabetes mellitus.