Atherosclerosis

Question 1

What is atherosclerosis?

Answer 1

-degeneration of the walls of the arteries
-caused by accumulated fatty deposits & scar tissue
-leading to restriction of the circulation & risk of thrombosis
-FIBROLIPID PLAQUES
-SYSTEMIC ARTERIES

Question 2

What is atheroma?

Answer 2

-the fatty material which forms deposits in the arteries

Question 3

How does atherosclerosis progress throughout life?

Answer 3

Birth - no atherosclerosis

Late teenage/early 20s - fatty streaks in aorta, may not progress to established atherosclerosis

30s/40s/50s - development of established atherosclerotic plaques

40s-80s - complications of atherosclerotic plaques, eg. thrombosis, intraplaque haemorrhage

Question 4

Where is atherosclerosis common?

Answer 4

High pressure systems, eg. aorta

Question 5

Fatty streaks

Answer 5

Potential start of atherosclerosis

Question 6

What is an atheroma composed of?

Answer 6

-lipids, eg. cholesterol
-calcium
-fibrous connective tissue
-macrophage cells
-cell waste

Question 7

Risk factors for atherosclerosis

Answer 7

-cigarette smoking
-hypertension
-poorly controlled diabetes mellitus (predominantly T2)
-hyperlipidemia

Question 8

Mechanism of formation of atherosclerotic plaques/atherosclerosis:

Answer 8

-lipid insulation theory is NOT correct
-ENDOTHELIAL DAMAGE THEORY
-endothelial cells are metabolically active, delicate cells, easily damaged
-endothelial cells damaged by: cigarette smoke (containing free radicals, nicotine, CO), shearing forces at arterial divisions, hypertension, diabetes, glycosylation products, hyperlipidaemia (direct damage to endothelial cells)
-cumulative damage leads to ulceration, microthrombi, eventual development of established atherosclerotic plaques

Question 9

What can cause a plaque to burst?

Answer 9

Haemorrhage

Question 10

What are complications of atherosclerosis?

Answer 10

-blocked pumping - complete blockage of artery by plaque (often due to superadded thrombosis or haemorrhage within the plaque) - no blood flow to organ supplied by blocked artery unless it has multiple arterial supply -> infarction

-embolism - pieces of plaque break off & travel downstream to block smaller vessels -> small infarcts distal to main atherosclerotic plaque

-infarction

Question 11

What are complications of atherosclerosis specific to certain organs?

Answer 11

-cerebral infarction
-carotid atheroma -> emboli causing TIAs or cerebral infarcts
-myocardial infarction -> cardiac failure
-aortic aneurysm - rupture causes sudden death
-peripheral vascular disease with intermittent claudication
-gangrene