Atherosclerosis
Atherosclerosis is a disease caused by arteriosclerosis, a process of thickening and stiffening of the arterial wall with progressive narrowing of the vascular lumen. 3 types of arteriosclerosis were identified depending on the size of the affected vessels as follows:
- Atherosclerosis affecting the middle and large muscular arteries being involved in the occurrence of acute coronary episodes, strokes, peripheral arterial disease and aortic aneurysm;
- Arteriolosclerosis affects the small arteries and arterioles and is often associated with metabolic diseases such as diabetes;
- Sclerosis and calcification of the average Monckeberg type (less common).
The formation of atheroma plaque in the process of atherosclerosis begins with the damaging of the arterial endothelium followed by the aggregation of foam cells and lymphocytes with the formation of atheromatous or fibroatheromatous plaques (formations with lipid nucleus and fibrous sheath) leading to progressive vascular occlusion with gradual narrowing of the lumen.
What are the causes of the atherosclerotic process
The causes of the initial endothelial lesion are due to metabolic (hyperlipidemia), mechanical (chronic hypertension) and immunological (presence of cytokines that cause inflammation of the vascular wall). Endothelial micro-lesions favor the adhesion and aggregation of the blood elements represented by platelets, monocytes and T-lymphocytes, contributing together with the proliferation of vascular smooth muscles to the formation of mature atheroma plaques.
The atheromas thus constituted evolve progressively with the gradual limitation in different degrees of the arterial blood flow, there being the risk of rupture or fissure with the appearance of acute syndromes due to ischemia in the territory of the affected artery.
Atheromatous formations that meet the following conditions are considered to be vulnerable plaques with a risk of rupture:
- Lipid-rich central nucleus;
- Thin outer shell;
- Existence of a diffuse inflammatory arterial process.
What are the symptoms of atherosclerosis?
The symptoms in arteriosclerosis are in most cases absent until the atheroma plaque ruptures, causing acute ischemia. Depending on the location of the obstructed vessel, the following moderate manifestations may be present:
- Angina pectoris (damage to the coronary arteries);
- Sudden numbness or weakness of the upper and/or lower limbs (cerebral arteries);
- Intermittent claudication (gait pain occurs in peripheral arterial disease);
- Renal failure (damage to the arteries that serve the kidneys).
Complete obstruction with stopping blood flow to the arteries to various systems and organs can cause acute myocardial infarction, stroke, kidney infarction, mesenteric infarction, limb gangrene and aortic dissection.
Atherosclerosis thus becomes a complex process with slow development closely dependent on the presence of risk factors, asymptomatic, which becomes clinically manifest as arterial blood flow narrows.
Treatment in atherosclerosis
The treatment of atherosclerosis has as its main objective to keep under control the risk factors (diabetes, hypertension, dyslipidemia) by changing the lifestyle (avoiding sedentary lifestyle) and diet (decreasing the dietary intake of unsaturated fats). Second, the administration of medication to reduce atherosclerotic progress aims to:
- Reduce cholesterol levels by using statins and fibrates;
- Prevent vasospasm by using angiotensin-converting inhibitors;
- Lowering blood pressure by taking beta-blockers or diuretics;
- Prevention of episodes of acute thrombosis by using antiplatelet agents.
Surgical treatment is aimed at severe cases that require thrombotic therapy (removal of intravascular thrombi), vascular bypass (deviation of circulation with obstruction of the obstructed vessel), angioplasty (placement of catheters with light distension with or without stent), atherectomy (removal of atheroma) or endarterectomy.