136. Atherosclerosis: definition of the concept, risk factors, developmental theories. Macro- and microscopic stages of atherosclerosis.

Atherosclerosis is a chronic disease based on a violation of fat and protein metabolism, characterized by damage to elastic and muscle – elastic arteries, deposition of lipids and proteins in the intima with a reactive proliferation of CT.

137. Atherosclerosis: definition, structure of stable and unstable atherosclerotic plaques. Complications and causes of death of patients.

Atherosclerosis is a chronic disease based on a violation of fat and protein metabolism, characterized by damage to elastic and muscle – elastic arteries, deposition of lipids and proteins in the intima with a reactive proliferation of CT.

The stability of the plaque depends on its structure, size and configuration. Stable plaques are static or have been characterized by slow growth for many years. Stable plaques are rich in collagen; unstable plaques are rich in lipids. Stable - thick fibrous capsule protecting the lipid nucleus - Narrowing of the vessel lumen - Revealed by angiography Unstable - well-preserved lumen - large lipid nucleus - thin fibrous capsule - decrease in the number of myofibroblasts, collagen fibers

Complications

1. Tendency to thrombosis and embolism;

2. Organ ischemia:

in the heart - coronary heart disease, fibrosis, myocardial infarction;

in the kidneys - chronic renal ischemia, chronic fibrosis, kidney failure; in the intestine - chronic intestinal ischemia; in the lower extremities - chronic ischemia with the formation of intermittent lameness and the development of gangrene;

3. Aortic aneurysm.

Causes of death: Atherosclerosis of the branches of the aortic arch leads to insufficient blood supply to the brain, which can lead to a stroke. And atherosclerosis of the coronary (coronary) arteries of the heart leads to the development of coronary heart disease.

138. Clinical and anatomical forms of atherosclerosis and related complications.

Depending on the predominant localization of atherosclerosis in the vascular basin, its complications and outcomes, its clinical and anatomical forms are distinguished:

– atherosclerosis of the aorta;

– atherosclerosis of the coronary arteries of the heart (cardiac form, coronary heart disease);

– atherosclerosis of the arteries of the brain (cerebral form, cerebrovascular diseases);

– atherosclerosis of the arteries of the kidneys (renal form);

– atherosclerosis of the intestinal arteries (intestinal form);

– atherosclerosis of the arteries of the lower extremities.

Aortic atherosclerosis is the most common form. It is more pronounced in the abdominal region and is usually characterized by atheromatosis, ulceration, and atherocalcinosis. In this regard, atherosclerosis of the aorta is often complicated by thrombosis, thromboembolism and embolism of atheromatous masses with the development of infarction (for example, kidneys) and gangrene (for example, intestines, lower extremity). Often, an aortic aneurysm forms on the basis of atherosclerosis — a bulging wall at the site of its lesion, ulceration is frequent.

Atherosclerosis of the coronary arteries of the heart is the basis of coronary heart disease.

Atherosclerosis of the cerebral arteries is the basis of cerebrovascular diseases. Prolonged cerebral ischemia due to stenosing atherosclerosis of the cerebral arteries leads to dystrophy and atrophy of the cerebral cortex, atherosclerotic dementia.

In atherosclerosis of the renal arteries, narrowing of their lumen by plaque usually occurs at the place of branching of the main trunk or dividing it into branches of the first and second order. Often the process is one—sided, less often it is two-sided. Either a wedge-shaped site of parenchymal atrophy with stroma collapse and replacement by connective tissue is formed in the kidney, or a heart attack with its subsequent organization and formation of a retracted scar. A large-browed atherosclerotic wrinkled kidney (atherosclerotic nephrosclerosis) occurs, the function of which suffers little, since most of the parenchyma is preserved. As a result of renal tissue ischemia in stenosing atherosclerosis of the renal arteries, symptomatic (renal) hypertension develops in some cases.

Atherosclerosis of the intestinal arteries, complicated by thrombosis, leads to intestinal gangrene. With atherosclerosis of the arteries of the extremities, the femoral arteries are more often affected. The process is asymptomatic for a long time due to the development of collaterals. However, with increasing insufficiency of collaterals, atrophic muscle changes develop, cold limbs appear, characteristic pain when walking — intermittent lameness. If atherosclerosis is complicated by thrombosis, gangrene of the limb develops — atherosclerotic gangrene.