Atheroma Flashcards
What are Atheroma/Atherosclerosis
Formation of focal elevated lesions (plaques) in intima of large and medium sized arteries
Complications of Atheroma
- In coronary arteries the atheromatous plaques narrow the lumen and cause ischaemia
- Angina due to myocardial ischaemia
- Complicated by thromboembolism
Ateriosclerosis
Age related change in muscular arteries
What causes decrease in vessel diameter in Ateriosclerosis (3)
• Smooth muscle hypertrophy, apparent reduplication of internal elastic laminae, intimal fibrosis
Stages of Atheroma (3)
Fatty Streak
Early Atheromatous Plaque
Fully developed atheromatous plaque
Features of fatty streak (4)
Seen in young children
No clinical significance
May disappear
Masses of lipid-laden macrophages
Features of early atheromatous plaque (3)
Seen in young adults onwards
Smooth yellow patches on instima
Lipid-laden macrophages
Features of fully developed atheromatous plaque
Central lipid core with fibrous tissue cap
Covered by arterial endothelium
Contains inflammatory cells (macrophages T-cells mast cells)
What cells produce collagen in fibrous cap
Smooth muscle cells
Where are the inflammatory cells recruited from
Arterial endothelium
What causes the macrophages to be foamy
Uptake of oxidised lipoproteins via specialised membrane bound scavenger receptor
What is Dystrophic calcification
calcification occurring in degenerated or necrotic tissue). Is extensive and occurs late in plaque development
Complications of Atheroma (3)
Haemorrhage into plaque
Plaque rapture/fissuring
Thrombosis
Aetiology of Atheroma (3)
Hypercholesterolaemia
Elevated levels of LDL (bad cholesterol)
Mutation in cell membrane receptors for LDL
Signs of major hyperlipidaemia (7)
Primary- familial Secondary- idiopathic Corneal arcus Tendon xanthomata Xanthelasmata Family history Biochemical
Risk Factors (5)
Smoking Hypertension Diabetes mellitus Male Elderly
Less Strong Risk Factors (5)
Obesity Lifestyle Socioeconomic status Low birthweight Micro-organism
2 Steps involved in the development of atheromatous plaque
- Injury to endothelial lining of artery
2. Chronic inflammatory healing and response of vascular wall to agent causing injury
Development of Atheromatous Plaque (7)
- Endothelial injury and dysfunction
- Accumulation of LDL in vessel wall
- Monocyte adhesion to endothelium –> migration into intima and transformation to foamy macrophages
- Platelet adhesion
- Factor release from activates platelets, macrophages leads to smooth muscle recruitment
- Smooth muscle cell proliferation, extracellular matrix production and T cell recruitment
- Lipid accumulation
Causes of endothelial injury
Haemodynamic disturbances (turbulent flow) Hypercholesterolaemia Endothelial cells release growth factors and cytokines
LDL accumulate and are modified by what
Free radicals produced by inflammatory cells
injured endothelial cells lead to (3)
- Enhances expression of cell adhesion molecules (ICAM-1, E-selectin)
- High permeability for LDL
- Increased thrombogenicity
Where do microthrombi form
Denuded areas
Consequences of Atheroma
- Progressive lumen narrowing due to high grade plaque stenosis
- Acute atherothrombotic occlusion
- Embolism of the distal arterial bed
- Ruptured atheromatous abdominal aortic aneurysm
