Atherosclerosis is a complex process that be can in a simplified way described as chronic vascular damage associated with progressive deposition of cholesterol and other fats in their walls. Our immune system also plays an important role in the formation of atherosclerotic fatty plates as it causes a chronic inflammation of atherosclerotic sites. The process happens by all people with greater or lesser severity and is associated with many complications. The main consequence is a gradual narrowing or a sudden complete obstruction of a blood vessel. Affected vessels in a certain place are start to narrow, blood flow worsens and certain organs may be endangered by the lack of oxygen (so called ischemia). As a very serious complication of atherosclerosis there is a situation when a small rupture of an atherosclerotic narrowing occurs. The blood vessel wall is suddenly damage which is followed by a blood clot formation (a thrombus). This blood clot quickly obstructs the affected artery and causes an acute shortage of oxygen to a certain organ with possible permanent damage.
There are numerous causes of atherosclerosis. They include age (the longer we live, the more worn out our blood vessels are), male gender (women are protected due to sex hormones) and genetic predisposition. There should be mentioned that after menopause when the production of sex hormones diminishes, women are at higher risk of atherosclerosis and cardiovascular diseases than men.
There are also many causes that can be prevented or treated successfully with a slight decrease of atherosclerosis risk.
Scheme of progression and complications of atherosclerosis
Symptoms and complications
As mentioned above the symptoms and complications related to atherosclerosis emerge because of a certain artery narrowing or because of its sudden obstruction. The most commonly affected are these vessels:
These two arteries carry blood into the brain. Carotid artery narrowing may be asymptomatic because in general there are four arteries providing blood flow for brain. An abrupt closure of a carotid artery by a blood clot (thrombus) can be followed by the thrombus ejection into brain blood vessels causing a typical ischemic stroke, often with lifelong consequences (paralysis, loss of body sensations, speech disruption etc.).
Renal (kidney) arteries
A chronic renal artery narrowing causes an irritation to the kidney by a reduced blood flow. The kidney secretes some hormones causing an increase in blood pressure. It is a defense mechanism but in this case it further aggravates the atherosclerosis. A classic vicious circle occurs.
The arteries of the lower limbs
Chronic narrowing of the blood vessels causes emergence of so called ischemic disease of lower limbs. Its main symptom is pain in affected leg while walking. This pain is caused by lack of tissue oxygen during exertion and quickly disappears when at rest. A sudden artery closure may cause death of the whole extremity (or its part) and without an emergent medical aid with subsequent amputation.
Aorta is the largest blood artery in our body. Atherosclerosis together with chronic high blood pressure may cause a weakening of its wall and the formation of aortic aneurysm.
The atherosclerotic process damages small retinal blood vessels and thus increases the risk of developing so called macular degeneration.
The presence of atherosclerosis can be assumed from some above mentioned clinical symptoms together with the presence of atherosclerosis risk factors. These include blood pressure check, Body Mass Index measure, cholesterol and blood sugar levels examination, etc.
An ultrasound with Doppler imaging is an examination that directly confirms artery narrowing and measures the blood flow in that location. In some vessels (renal vessels, lower limbs) an angiography is the best choice to diagnose atherosclerotic changes. Computed tomography often randomly shows calcified atherosclerotic plates in large vessel like in aorta but we do not use it as a primary atherosclerosis diagnostic examination.
Prevention and treatment
Prevention and treatment of atherosclerosis are based on its causes. These causes must be prevented or treated; proper ways of treatment are stated in relevant articles dedicated to these conditions. In this article let’s just say that there are lifestyle measures (diet, physical activity), drugs (typically hypolipidemic agents) and endovascular or surgical procedures performed by a sudden artery closure.