Atherosclerosis: Definition and Pathogenesis

Definition and Etiology

• Atherosclerosis is a chronic inflammatory disease of the arterial wall characterized by the progressive accumulation of lipids, inflammatory cells, and fibrous tissue.
• It is the leading cause of cardiovascular diseases (CVDs) globally.
• The disease process begins with endothelial dysfunction, a disruption of the inner lining of the arteries.
• Contributing factors include:
  • Elevated levels of low-density lipoprotein cholesterol (LDL-C).
  • Hypertension.
  • Smoking.
  • Diabetes.
  • Obesity.
  • Genetic predisposition.
  • High levels of homocysteine.

Pathogenesis

• The initial lesion, a fatty streak, develops when LDL-C penetrates the endothelium.
• Macrophages engulf oxidized LDL-C, transforming into foam cells.
• Inflammation is triggered and attracts other immune cells, especially T lymphocytes.
• Smooth muscle cells from the arterial wall migrate and proliferate, further contributing to plaque formation.
• The plaque progressively grows, narrowing the arterial lumen and potentially leading to complete occlusion.
• Plaque rupture or erosion is a critical event in the development of acute coronary syndromes (ACS) – like heart attacks and strokes.

Types of Atheromatous Lesions

• Fatty streaks, a precursor to more advanced lesions.
• Fibrous plaques, characterized by a fibrous cap over a lipid core.
• Complicated plaques, with potential for rupture or ulceration, increased risk of thrombosis.

Clinical Manifestations

• Atherosclerosis is often asymptomatic in its early stages.
• Symptoms emerge when the plaque compromises blood flow to organs.
• Angina, a chest pain caused by reduced blood supply to the heart.
• Stroke resulting from impaired blood supply to the brain.
• Peripheral artery disease (PAD), causing pain in the extremities.
• Transient ischemic attack (TIA), a temporary interruption of blood supply to the brain.

Risk Factors Modifications

• Lifestyle changes are crucial in preventing and managing atherosclerosis.
• Healthy diet low in saturated and trans fats.
• Regular physical activity.
• Smoking cessation.
• Weight management to maintain a healthy BMI.
• Blood pressure control.
• Management of diabetes.
• Regular cholesterol screenings and medication if necessary.

Diagnostic Methods

• Physical examination and medical history.
• Lipid profile blood tests to measure cholesterol levels.
• Imaging techniques to visualize the arteries:
  • Angiography.
  • Ultrasound.
  • CT scans.
  • MRI scans.

Prevention and Treatment Strategies

• Lifestyle modifications to control risk factors are fundamental.
• Medications including statins to lower LDL-C levels.
• Antiplatelet therapy to prevent blood clots.
• Antihypertensive medications to control blood pressure.
• Antidiabetic medications to control blood glucose.
• Procedures like angioplasty and stenting to restore blood flow.
• Surgical interventions such as bypass grafting for severe blockages.

Complications

• Myocardial infarction (heart attack).
• Stroke.
• Peripheral artery disease (PAD).
• Renal artery stenosis.
• Aortic aneurysm.

Future Research Directions

• Further understanding of the mechanisms involved in the development and progression of atherosclerosis.
• Exploring novel therapies to prevent and treat atherosclerosis.
• Investigating the role of genetics in the development of atherosclerosis.
• Developing more sophisticated biomarkers to detect and monitor atherosclerosis.
• Improved understanding and treatment of endothelial dysfunction.

Ce quiz explore la définition et l'étiologie de l'athérosclérose, une maladie inflammatoire chronique des parois artérielles. Vous découvrirez les facteurs contribuant à cette affection et le processus de formation de plaques dans les vaisseaux sanguins. Testez vos connaissances sur cette cause principale des maladies cardiovasculaires.