Atherosclerosis

Question 1

What is atherosclerosis?

Answer 1

Chronic inflammatory process affecting the intima of the arteries. Characterised by the formation of lipid-rich plaques in the vessel wall.

Question 2

What are the modifiable risk factors for atherosclerosis?

Answer 2

Smoking, HTN, DM, dyslipidaemia, obesity, poor diet, lack of exercise.

Question 3

What is the underlying aetiology of atherosclerosis?

Answer 3

1. Damaged endothelium becomes dysfunctional (increased permeability, adhesion molecules and cytokines produced).
2. Recruitment of inflammatory cells - LDL oxidation, foam cells form which produce growth factors.
3. Stimulates migration of smooth muscle cells to intima from media.

Question 4

What determines the stability of an atherosclerotic plaque and why?

Answer 4

Balance between number of smooth muscle cells and number of inflammatory cells in fibrous cap.

1. Inflammatory cells destabilise plaques by producing MMPs which digest fibrous cap, also apoptosis of SM cells.
2. SM cells produce the fibrous cap to stabilise, also produce inhibitors of MMPs.

Question 5

What are the complications of atherosclerosis?

Answer 5

1. Gradual enlargement of stable plaque - stenosis, ischaemia.
2. Sudden disruption of vulnerable plaque - exposes tissue factors and pro-thrombotic substances, thrombus formation.
3. Aneurysm formation - weakening of media (rupture and thrombus formation which can embolise)