Atherosclerosis

Question 1

Define atherosclerosis

Answer 1

accumulation of intracellular and extracellular lipids in the intima of large and medium sized arteries
(arteriosclerosis = smaller sized arteries)

Question 2

What happens to the arterial walls during atherosclerosis?

Answer 2

Thicken and elasticity is lost

Question 3

What is Monkeberg’s disease?

Answer 3

Calcification of the media of large arteries

Question 4

What is atheroma and what does it consist of?

Answer 4

The necrotic core of atherosclerotic plaque.

It consists of dead cells, debris and cholesterol crystals

Question 5

What are MACROscopic features of atherosclerosis?

Answer 5

• Fatty streaks = lipid deposits in the intima (yellow)
• Simple plaques = development from fatty streaks (yellow to white)
• Complicated plaques = calcified

Question 6

What are MICROscopic features of atherosclerosis?

Answer 6

• Fibrosis
• Necrosis
• Cholesterol clefts
• Disruption of internal elastic lamina
• Ingrowth of small vessels in adventitia

Question 7

What are some plaque formation complications?

Answer 7

• Ulceration
• Thrombosis on plaque
• Spasms at the site
• Embolisation
• Calcification
• Aneurysm formation

Question 8

What are some clinical effects of atherosclerosis?

Answer 8

• Ischaemic heart disease (e.g. sudden death, MI)
• Cerebral ischaemia (e.g. cerebral infarction)
• Mesenteric ischaemia (e.g. intestinal infarction)
• Peripheral vascular disease (e.g. gangrene, Leriche syndrome)

Question 9

What are aneurysms?

Answer 9

Local dilations of an artery from weakened arterial wall (elastic tissue destroyed)

Question 10

What are the 4 proposed theories for Atherogenesis?

Answer 10

1) Thrombogenic theory
2) Insudation theory
3) Reaction to injury theory
4) Monoclonal hypothesis

Question 11

What happens in thrombogenic theory (encrustation hypothesis)?

Answer 11

Plaques formed by repeated thrombi

-lipid core derived from thrombi

Question 12

What happens in insudation theory?

Answer 12

1) Endothelial injury
2) Inflammation
3) Increased permeability to lipids from plasma

Question 13

What happens in reaction to injury theory?

Answer 13

Plaques form in response to endothelial injury

• injury increases permeability and allows platelet adhesion
• monocytes penetrate endothelium
• smooth muscle cells proliferate and migrate

Question 14

What happens in monoclonal hypothesis?

Answer 14

Plaques are monoclonal

• raises question wether they are from benign neoplastic growths
• could they have a viral aetiology?

Question 15

What are non-modifiable risk factors for atheroscleorsis?

Answer 15

• Age
• Gender (women protected relatively before menopause)
• Genetic predisposition (familial hyperlipidaemia and genetic variations in apoE)

Question 16

What are modifiable risk factors of atherosclerosis?

Answer 16

• Cigarette smoking
• Hypertension
• Hyperlipidaemia
• Infections (e.g. chlamydia pneumoniae)
• Obesity
• Alcohol consumption

Question 17

Describe a unified hypothesis of atherogenesis

Answer 17

1) Chronic endothelial insult (e.g. from hypertension)
2) Lipid droplets and monocytes cross endothelium to intima
3) Lipids get oxidised and they get ingested by macrophages = turn into foam cells
4) Fatty streaks start to form as foam cells and smooth muscle cells proliferate and migrate
5) Further growth of fatty streaks lead to development of a plaque
6) Cells in the centre of the plaque die and necrosis develops

Question 18

How can atherosclerosis be prevented?

Answer 18

• no smoking
• reduce fat intake
• treat hypertension
• decrease alcohol intake
• regular exercise

Question 19

What are some intervention strategies for atherosclerosis?

Answer 19

• Modify diet
• Lipid lowering drugs e.g. statins
• Treat diabetes
• Thrombolysis