Atheroma

Question 1

What is the process of atheroma?

Answer 1

Atherosclerosis

Question 2

What is atheroma?

Answer 2

The formation of focal elevated lesions (plaques) in intima of large and medium sized arteries

Question 3

Give an example of somewhere that plaques may form that has clinical implications

Answer 3

Coronary arteries - atheromatous plaques narrow lumen - ischaemia of the myocardium (clinical manifestation is angina)

Question 4

What is meant by a complicated plaque?

Answer 4

When the plaque ruptures (atheromatous plaque - lipid-rich core and fibrous cap)

Question 5

What causes 90% of MI’s?

Answer 5

Rupture of a plaque in the coronary artery - thrombus/blood clot forms on top therefore occluding the lumen (blocking blood supply to the myocardium)

Question 6

What effect does blocking the blood flow to the myocardium have?

Answer 6

Ischaemia -> infarction

Question 7

What is stable angina?

Answer 7

Predictable chest pain that comes on in exertion

Question 8

What causes the pain felt in stable angina?

Answer 8

Increased oxygen demand of the myocardium

Question 9

What is unstable angina?

Answer 9

Unpredictable chest pain that comes on at rest

Question 10

What causes the pain felt in unstable angina?

Answer 10

Decreased oxygen supply by the coronary arteries

Question 11

What is a thromboembolism?

Answer 11

Obstruction of a blood vessel by a blood clot that has become dislodged from another site in the circulation

Question 12

What colour is plaques in the intima?

Answer 12

Yellow

Question 13

What is arteriosclerosis?

Answer 13

Not atheromatous plaques - age related changes in muscular arteries (thickening and hardening of the walls of the arteries), decreasing vessel diameter

Question 14

What should the diameter of the intima be?

Answer 14

Thin

Question 15

What is a fatty streak?

Answer 15

Earliest significant lesion in young children - yellow linear elevation of intimal lining due to masses of lipid-laden macrophages (no clinical significance and may disappear, however, patients at risk can go onto form atheromatous plaques)

Question 16

What is the next stage?

Answer 16

Early atheromatous plaque - young adults onwards, smooth yellow patches in intima due to lipid laden macrophages (progress to established plaques)

Question 17

What is a fully developed atheromatous plaque?

Answer 17

Central lipid core with fibrous cap, covered by arterial endothelium

Question 18

What holds the structure of the plaque?

Answer 18

Collagens (produced by smooth muscle cells - in tunica media) in cap provide structural strength

Question 19

What are foamy macrophages?

Answer 19

Macrophages that appear foamy due to their uptake of oxidised lipoproteins

Question 20

What is the lipid core made up of?

Answer 20

Rich in lipids and debris derided from macrophages

Question 21

What occurs late in plaque development and is often a marker on angiograms/CT?

Answer 21

Calcification

Question 22

What is the most important risk factor for atheroma?

Answer 22

Hypercholesterolaemia

Question 23

What is bad cholesterol?

Answer 23

LDL

Question 24

How many Caucasians are heterozygous for a mutation that causes a genetically determined lack of cell membrane receptors for LDL?

Answer 24

1/500

Question 25

How many patients in the UK are homozygous for this mutation?

Answer 25

1 in 1 million - usually die from coronary artery disease in teens - the defect makes the body unable to remove LDL (bad) cholesterol from the blood - this results in a high level of LDL in the blood

Question 26

What are some signs of major hyperlipidaemia?

Answer 26

``` Familial Biochemical evidence Corneal arcus Tendon xanthomata Xanthelasmata ```

Question 27

What are the other risk factors for atheroma?

Answer 27

``` Smoking (damages vessel walls) Hypertension (damages vessel walls) Diabetes (damages vessel walls) Male Elderly ```

Question 28

What are some less strong risk factors for atheroma?

Answer 28

Obesity Sedentary lifestyle Low socio-economic status Low birthweight

Question 29

What is the two step process that causes the development of atheromatous plaques?

Answer 29

Injury to endothelial lining of artery | LDL passes through endothelium of blood vessel and lodges in the intima

Question 30

What are patients given who have high cholesterol?

Answer 30

Statins - lower LDL cholesterol and increase HDL cholesterol

Question 31

What is the difference in vessel lumen between stable angina and unstable angina?

Answer 31

Stable angina is stenosed coronary artery Unstable angina is very stenosed coronary artery - they don't need to exert themselves for the lack of oxygen and blood flow to be noticeable

Question 32

What is ischemic pain of myocardium called?

Answer 32

Angina

Question 33

What happens when an artery in the legs gets stenosed?

Answer 33

Intermittent clauducation - clinical manifestation of peripheral arterial disease (muscles in the legs don't get enough blood and therefore oxygen when you exercise - pain stops when you stop walking)

Question 34

What does total occlusion of the coronary artery, carotid artery and the popliteal artery cause?

Answer 34

Myocardial infarct Cerebral infarct Lower limb gangrene (infarct)

Question 35

What can embolic occlusion of small vessels cause?

Answer 35

Small infarcts in organs

Question 36

What can happen with a thrombus in artery?

Answer 36

Small thrombus fragments can detach and embolise

Question 37

What can a plaque cause (not including if it ruptures)

Answer 37

Can cause the media below to become weak and therefore cause an aortic aneurysm (often asymptomatic and sudden rupture has a high mortality)

Question 38

What plaques have a high risk of rupture?

Answer 38

Typically thin fibrous cap, large lipid core and prominent inflammation

Question 39

What are ways to help prevent atheroma?

Answer 39

``` Stop smoking Control blood pressure Weight loss Regular exercise Dietary modifications Cholesterol lowering drugs ``` (aspirin - inhibits platelet aggregation to decrease the risk of thrombus forming on established plaques)

Question 40

What is vascular disease?

Answer 40

Atherosclerosis in all different places - can cause heart attacks, strokes and peripheral vascular disease