Coronary Artery Disease: Atherosclerosis

Question 1

Coronary defenition:

Answer 1

Relating to the arteries which surround and supply the heart

Question 2

Atherosclerosis definition:

Answer 2

Atheroma; fatty plaque deposit

Sclerosis; Hardening

Question 3

Coronary Atherosclerosis:

Answer 3

Disease in which plaque builds up inside arteries supplying the heart. Plaque harderns over time and the build-up causes the inside of arteries to become narrower, slowing down blood flow and increasing the pressure in the arteries.

Question 4

What does a decrease in Arteries compliance lead to?

Answer 4

Hypertension, can also lead to Ischaemia

Question 5

WHat is ischaemia

Answer 5

Lack of Oxygen in distal tissues that can spread through the body.

Question 6

Consequenses of Atherosclerosis at: The cerebral and carotid arteries

Answer 6

Cerebovascular disease: stroke, vascular dementia, ischaemic transient heart attack

Question 7

Consequenses of Atherosclerosis at: The renal arteries

Answer 7

Renovascular disease

Question 8

Consequenses of Atherosclerosis at: The Aeorta

Answer 8

Aortinc aneurusm- swelling and rupture of aneurusm almost always fatal

Question 9

Consequenses of Atherosclerosis at: Legs and Arms

Answer 9

Claudation (amputation if severe)

Peripheral gangrene - ischaemic tissue damage (amputation)

Question 10

Endothelium Dysfunction is:

Answer 10

1. the target of almost all CVD risk factors
2. Involves Vascular and Cardiac
3. Is the initiating factor in atherosclerosis
4. indicated before any strucutral damage to vasculature is seen
5. Associated with the progression of almost all aquired CVD

Question 11

What is the endothelium structure?

Answer 11

It is the innermost layer in the arteries: a single cell layer, and elongated in direction of flow.

Question 12

What is the dysfunction in the endothelium?

Answer 12

A defect in the Nitrogen Oxide production causes impaired endothelim-dependant vasodilation which signals dysfunction, causing increased endothelin (ET-1) and reactive Oxygen species production

Question 13

What is Atherosclerosis in response to injury also known as?

Answer 13

Atheroma.

Question 14

Describe the formation of fatty streaks in the arteries (atherosclerosis):

Answer 14

If an intact endothelium is damaged due to injury, there is an increased permeability through the spacing of the endothelial cells.
This causes accumulation of oxidised LDL in the sub-endothelial space causing inflammation and thus promoting atherosclerosis.
There is also leukocyte adhesion across the endothelium intitiating inflammation.
Monocytes stick to the loosening endothelial cell junctons and differentiate into macrophages.
The macrophages engulf LDL by phagocytosis forming FOAM CELLS (fatty streaks).
This stage is early and reversible

Question 15

What happens if the fatty streaks progress?

Answer 15

There is more plaque growth by further LDL deposition in the intima (second inner-most layer after the endothelium)
This causes arterial re-modelling to try to compensate the plaque build-up and maintain the lumen size and blood flow.
Once the external adventita (outer layer of the endothelium) cannot expand any more, the artery cannot compensate for plaque build up and the plaque growth protrudes the lumen forming a fibrous cap.
If the plaque ruptures, it can cause a thrombus clot and is a medical emergancy.

Question 16

What do we know aout healed plaques?

Answer 16

They have higher fibrotic content, will still protrude but are more stable and less likely to rupture.

Question 17

What does the time it takes for Atheroma to develop depend on?

Answer 17

It normally takes years, depending on the intensity of exposure to risk factors.

Question 18

What is the primary risk of atheroma?

Answer 18

Endothelial Dysfunction causing disruption to the autocrine, endocrine and paracrine function.

Question 19

WHat are the other risks of Atheroma?

Answer 19

• Diabetes
• Hypertension
• Hyperlipidameia/ high cholesterol
• Metabolic syndrome (increased abdominal fat)
• Smoking (infection of the endothelium)

Question 20

What do all the risk factors cause?

Answer 20

An increase in cytokines, cellular proliferation, lipid accumulation, inflammation adn calcification (build up of calcium, hardenin vessels). These all lead to the development of Athroma and Coronary Artery Disease.

Question 21

WHat is Coronary Atheroma disease?

Answer 21

Atheroma anywhere in the major epicardial (layer of the heart wall) coronary arteries

Question 22

Where does the Athroma often build up?

Answer 22

In the tortuosity and bifurcations (twists and bends) where there is turbulent flow and endothelial shear stress. It is asymptomatic (no symptoms)

Question 23

What is Collateral vessel formation?

Answer 23

Only happens in some individuals where accessory side branches form if there is partial or full blockage of the original vessel.

Question 24

How is Collateral vessel formation stimulated?

Answer 24

It is stimulated by various growth factors and is upregulated in response to chronic or repetitive ischaemia.

Question 25

What is good about Collateral vessel formation?

Answer 25

It is a benefit in bypassing the blockage in the main artery and supply enough oxygenated blood to enable the cardiac tissue to survive and recover.
It is only a superficial solution and will supply 25% of required blood.