Atherosclerosis

Atherosclerosis (from Ancient Greek ἀθήρα, meaning mush, and σκληρός, meaning hard) is a chronic disease of elastic and muscular–elastic arteries characterized by the deposition and accumulation of lipids (primarily cholesterol) within the inner layer of the arterial wall. This process leads to the formation of atherosclerotic plaques, which narrow the vessel lumen, thicken and deform the arterial wall, and reduce its elasticity.

Atherosclerosis is a systemic process that underlies the majority of cardiovascular diseases, which remain the leading cause of mortality worldwide. Atherosclerotic vascular disease is the primary cause of coronary artery disease, myocardial infarction, most ischemic strokes, and peripheral arterial disease.

Aetiology and Pathophysiology

The development of atherosclerosis is a complex, long-term process that begins with damage to the inner lining of the artery — endothelium. This injury triggers a cascade of pathological events.

1. Endothelial damage: Occurs under the influence of risk factors (hypertension, toxins from cigarette smoke, and hyperglycemia).
2. Lipid infiltration: Through the damaged endothelium, low-density lipoproteins (LDL, “bad cholesterol”) penetrate the arterial wall.
3. Inflammatory response: LDL particles undergo oxidation and are engulfed by macrophages, which transform into foam cells, forming the core of the developing plaque.
4. Plaque formation: Connective tissue proliferates around the lipid-rich and foam cell core, forming a fibrous cap. As the plaque enlarges, it progressively narrows the arterial lumen (stenosis).
5. Complications: The most dangerous event is rupture of the fibrous cap. It exposes plaque contents to the bloodstream and triggers rapid thrombus formation. The resulting clot may completely occlude the artery, causing acute cessation of blood flow.

Main risk factors:

• Nonmodifiable: Old age, male sex, positive family history.
• Modifiable: Dyslipidemia (elevated LDL), arterial hypertension, smoking, diabetes mellitus, obesity, physical inactivity.

Clinical significance

Atherosclerosis may remain asymptomatic for decades. Clinical manifestations typically occur when arterial narrowing exceeds 50–70 percent or when plaque ruptures with subsequent thrombosis. Symptoms depend entirely on the vascular territory involved.

• Coronary arteries: Coronary artery disease, presenting as angina pectoris (exertional chest pain) or myocardial infarction in case of acute thrombosis.
• Cerebral arteries (carotid and vertebral): Cerebrovascular disease, manifesting as transient ischemic attacks or ischemic stroke.
• Lower extremity arteries: Peripheral arterial disease, classically presenting with intermittent claudication (calf pain during walking).
• Renal arteries: May lead to renovascular hypertension.

Treatment and Prevention

The cornerstone of atherosclerosis management is prevention and elimination of modifiable risk factors, including control of blood pressure and blood glucose, smoking cessation, adherence to a diet low in saturated animal fats, and regular physical activity. The gold standard of pharmacologic therapy is statins, which lower serum cholesterol levels and stabilize atherosclerotic plaques, thereby reducing the risk of rupture. Antiplatelet agents (aspirin) are widely used to prevent thrombotic complications. In cases of critical arterial stenosis, invasive interventions are indicated, including balloon angioplasty with stent placement or open surgical procedures, such as coronary artery bypass grafting and carotid endarterectomy.