Atherosclerosis

What is Atherosclerosis?

Atherosclerosis is a multifactorial degenerative disease, which affects the arteries of medium and large caliber, inflaming and stiffening them due to the deposition of fat and white blood cells in their walls. These deposits (called atheromas or atherosclerotic plaques) are deposited in the innermost layer of the arteries, the one in direct contact with the blood.

In Italy and in many other countries of the world, atherosclerosis represents a health problem of primary importance, mostly linked to the lifestyle typical of industrialized societies. In turn, atherosclerosis is the cause or contributing cause of very serious diseases. such as angina pectoris, heart attack and stroke.

Why is it dangerous?

Often, atherosclerosis is described in a simplistic way as a pathology linked to fatty deposits on the walls of the arteries which, over time, increase in volume, reducing their elasticity and hindering blood flow.In reality, very often, it is not the occlusion of the artery itself that causes the heart attack but the inflammation and consequent breakdown of these adipose accumulations (called atheromas or atherosclerotic plaques).

When the surface wall of the plaque breaks, the blood comes into contact with the cholesterol contained in it. This process leads to the formation of a clot, just like it happens when we get a wound. Inside the artery the mechanisms of coagulation thus give rise to a hard substance (thrombus or caugule), which can interrupt the blood flow causing a sudden enlargement of the plaque.

Due to the injury, a small piece of atheroma could also detach which, transported to the periphery by the blood, would occlude smaller vessels (embolism).

The reason why some plaques break is mainly related to their chronic inflammation.

Insights

How Does Atherosclerosis Form?

Cholesterol is a fat and as such cannot dissolve in the blood. For this reason it is transported into the circulation by some specific proteins. Some of these, called LDL, transport it from the liver to the various tissues, where it is used for cellular metabolic processes.

If it is present in excess, the cholesterol linked to LDL tends to remain in the circulation for a long time and to slip immediately under the internal surface of the artery in question. Once entered here, the LDL undergoes modifications, oxidizing and increasing permeability of the vascular endothelium to monocytes and T lymphocytes (particular types of white blood cells) which thus migrate inside the wall.

Over time these cells evolve into macrophages and ingest the oxidized LDL accumulating lipid vacuoles in the cytoplasmic space (foam cells).

The foam cells secrete inflammatory substances and growth factors that induce proliferation of smooth muscle fiber cells. This situation leads to the formation of a fibrous capsule that covers the adipose accumulation. The fibrolipidic plaques are generated during the silent phase of atherosclerosis, which can last for decades.

These plaques are dynamic structures, in continuous evolution and the events of atherosclerosis are extremely variable and complex.

In the most serious cases, the fibrous plaques can undergo further complications due to the deposition of calcium crystals and subsequent calcification (obstruction of the blood flow), or to the development of fissures, hematomas and thrombi, responsible for the clinical phenomena of atherosclerosis (heart attack, angina unstable, stroke etc.).

The evolution of atherosclerosis is strongly linked to the lipid and macrophage content of the plaque and a high presence of these two elements increases its susceptibility to breakage.

The cardiovascular risk is therefore linked to both the size of the plaques and their inflammation. Relatively small but inflamed plaques are more dangerous than large, non-inflamed plaques.

C-reactive protein

A nonspecific indicator of the inflammatory process is the C reactive protein or PCR. Levels of this protein are generally high in those who suffer a heart attack and for the same cholesterol value, patients with higher than average PRC levels are at greater risk.

The increase in these values can be linked to inflammatory phenomena of various kinds (tonsillitis, bronchitis, pneumonia, etc.). To evaluate the cardiovascular risk it is therefore extremely important to carry out the test in perfect health conditions, possibly repeating it shortly after. .

The CRP value - together with that of total and HDL cholesterol, blood sugar, blood pressure and the "lifestyle analysis (smoking, stress, physical activity, etc.)." - can give an idea of what the cardiovascular risk is of the subject.