Session 6

Question 1

Define atheroma

Answer 1

The accumulation of intracellular and extracellular lipid I’m the intima and media of large and medium sized vessels

Question 2

Define atherosclerosis

Answer 2

The thickening and hardening of arterial walls as a consequence of atheroma

Question 3

Define arteriosclerosis

Answer 3

The thickening of walls of arteries and arterioles usually as a result of hypertension or diabetes mellitus.

Question 4

What are the macroscopic morphological features of atheroma?

Answer 4

Fatty streak (starting point) - lipid deposits in the intima. Yellow and slightly raised.
Simple plaque - raised yellow/white. Irregular outline. Widely distributed. Enlarge and coalesce.
Complicated plaque - thrombosis. Haemorrhage into plaque. Aneurysm formation.

Question 5

What are the microscopic morphological feature of atheroma?

Answer 5

Early changes - proliferation of SMCs. Accumulation of foam cells and extracellular lipid.
Later changes - fibrosis necrosis, cholesterol clefts and inflammatory cells. There is a disruption of the internal elastic lamina so the damage extends to the media. There is an ingrowth of blood vessels and plaque fissuring.

Question 6

Where are common sites for atheroma?

Answer 6

Aorta - especially abdominal
Coronary arteries
Carotid arteries
Cerebral arteries
Leg arteries

Question 7

Describe the cellular events leading to the formation of an atherosclerotic lesion

Answer 7

Chronic endothelial injury
Endothelial dysfunction with platelet adhesion and monocyte accumulation with release of growth factors and cytokines
Smooth muscle emigration from media into intima
Macrophages and SMC engulf lipid to form foam cells
Smooth muscle proliferation, collagen and matrix deposition, extracellular lipid deposition and neurovascularisation.

Question 8

What are the possible effects of ischaemic heart disease?

Answer 8

Sudden death, MI, angina pectoris, arrhythmias and cardiac failure

Question 9

What are the possible effects of cerebral ischaemia?

Answer 9

Transient ischaemic attack (mini stroke - symptoms for 24 hours)
Cerebral infarction (stroke)
Multi infarct dementia

Question 10

What are possible effects of mesenteric ischaemia?

Answer 10

Ischaemic colitis
Malabsorption
Intestinal infarction

Question 11

How does peripheral vascular disease present?

Answer 11

Intermittent claudification
Leriche syndrome - buttock claudification with erectile dysfunction
Ischaemic rest pain
(Eventually) gangrene

Question 12

What are the risk factors for atheroma?

Answer 12

Age
Gender - women protected before menopause
Hyperlipidaemia - e.g. Familial hypercholesterolaemia
Cigarette smoking
Hypertension - causes endothelial damage
Diabetes mellitus
Alcohol consumption >5 units/day
Infection - chlamydia, helicobacter pylori
Genetic predisposition
Lack of exercise, obesity
Stress
Oral contraceptives

Question 13

What are the cells involved in atheroma?

Answer 13

Endothelial cells - key role in haemostasis. Altered permeability to lipoproteins. Production of collagen.
Platelets - key role in haemostasis.
SMCs - take up lipids to become foam cells. Synthesise ECM materials
Macrophages -oxidise LDL. Take up lipids to become foam cells.
Lymphocytes - TNF may affect lipoprotein metabolism.
Neutrophils - secrete proteases leading to local damage and inflammation.
All (except SMCs and neutrophils) stimulate SMC proliferation and migration

Question 14

What are prevention measures for atheroma?

Answer 14

Stop smoking
Modify diet
Treat hypertension and diabetes
Lipid lowering drugs
Aspirin
Regular exercise