1. 📌 Essentials

• Atherosclerosis is a chronic disease characterized by fatty deposits in arterial walls causing stenosis.
• Primarily affects medium to large arteries like coronary, carotid, and peripheral arteries.
• Initiates with endothelial dysfunction due to risk factors such as hypercholesterolemia, hypertension, smoking, and diabetes.
• Lipid infiltration, especially oxidized LDL, promotes inflammation and foam cell formation.
• Progressive stages include fatty streaks, fibrous plaques, and complicated lesions.
• Stable plaques are collagen-rich; unstable plaques are lipid-rich and prone to rupture.
• Critical stenosis >70–75% causes ischemic symptoms; rupture can lead to thrombosis.
• Clinical manifestations include angina, MI, stroke, limb ischemia, often asymptomatic early.
• Plaque development is a slow process spanning decades, beginning in youth.
• Morphological evolution: fatty streak → fibrous plaque → calcified and complex plaque.

2. 🧩 Key Structures & Components

• Endothelium — lines arteries, regulates vessel permeability and tone.
• Lipid core — composed of cholesterol, phospholipids, necrotic debris.
• Foam cells — macrophages engorged with oxidized LDL.
• Vascular smooth muscle cells (VSMCs) — migrate, proliferate, produce collagen.
• Fibrous cap — collagen layer stabilizing plaque.
• Necrotic core — lipid and cell debris prone to rupture.
• Calcifications — deposits within chronic plaques.
• Thrombus — clot…