Unit 6: Atherosclerotic plaque

Question 1

What is the primary carotid disease?

Answer 1

Atherosclerosis

Question 2

What are some other carotid diseases encountered by vascular technologist?

Answer 2

• Dissection
• Thrombosis
• Fibromuscular dysplasia
• Kinking
• Carotid body tumor
• Aneurysm/pseudoaneurysm
• Subclavian steal

Question 3

What does atheroma mean?

Answer 3

greek for porridge or gruel.

Question 4

What are macrophages?

Answer 4

Large white blood cells, eating cells, may be found in tissue or moving through blood flow.

Question 5

What is a fibrous cap?

Answer 5

It is a protective layer over atheromatous core of lipids or necrotic debris seperating it from the lumen.

Question 6

What can a plaque be or contain?

Answer 6

• Fibrous
• Fatty
• Calcific
• Necrotic core

Question 7

What is the dysfunction of endothelial cells?

Answer 7

Atherosclerosis

Question 8

What are the hemodynamics (forces) associated with athersclerosis?

Answer 8

• Oscillatory flow
• Turbulence (post-stenosis)
• Low shear stress.

Question 9

What is the difference between typical stress and shear stress?

Answer 9

Typical stress→ arises from the force perpendicular to the material cross section on which it acts.

Shear stress→ it is the force parallel to the cross section. Friction of blood rubbing along the wall as it flows. ( think of friction in a landside.)

Question 10

Where does plaque usually form?

Answer 10

In areas of low shear stress.

Question 11

What are some risk factors for athersclerosis?

Answer 11

• Hypertension
• diabetes
• High cholestorol
• Smoking
• Obesity
• Physical inactivity
• Renal failure

Question 12

What are the 3 arterial layers?

Answer 12

1. Intima
2. Media
3. Adventitia

Question 13

What is the intima?

Answer 13

It is the single layer of endothelial cells.

Question 14

What do risk factors do to the endothelial cells?

Answer 14

1. It creates dysfunctional endothelial cells which causes monocytes (WBC) to adhere to endothelial cells.
2. This combo enables them to move to the intima-media layer
3. A NEOINTIMAL layer is formed below the endothelial cells.
4. Monocytes become macrophages
5. Macrophage become foam cells as they ingest cholestoral and oxidized lipids.

Question 15

AN early lesion, aka “fatty streak” (type 1) will form:

Answer 15

• Foam cells
• Lipid droplets in smooth muscle
• Appears as a yellowish streak in the wall
• May progress or be reversed through excersise and control of risk factors.

Question 16

What happens as plaque starts to grow?

Answer 16

The artery dilates to compensate and then the wall remodels to increase lumen size

Question 17

When does glagovian remodeling occur?

Answer 17

It occurs in response to wall shear stress.

Question 18

What happens when the artery cannot enlarge any further?

Answer 18

Plaque may grow to narrow the lumen.

Question 19

What does a atheroma consist of

Answer 19

Lipid core, smooth muscle cell displacement with a matrix.

Question 20

When would an atheroma cause symptoms?

Answer 20

If a peice break off and move downstream as emboli

Question 21

When do fiborous plaque occur?

Answer 21

Occurs over the age of 40

Question 22

What does a fibrous plaque have?

Answer 22

It has a lipid core with a fibrous cap.

Question 23

What does a fibrous cap do?

Answer 23

It seperates the core and lumen. It can also disrupt and cause thrombosis which may in turn block flow or break off and become emboli.

Question 24

What is a necrotic core?

Answer 24

It is a region of a plaque that is made up of primarily dead macrophage foam cells.

Question 25

What are 4 types of complicated lesions?

Answer 25

1. Hemorrhage within plaque
2. Necrosis
3. Thrombosis of lumen
4. Ulceration of plaque

Question 26

What does a dangerous plaque have?

Answer 26

It has a large/lipid/necrotic core close to a thin/disrupted fibrous cap, few smooth muscle cells and many macrophages.

Question 27

What does a rupture of plaque cause?

Answer 27

It allows emboli to escape from the plaque.

Question 28

What can happen to a ruptured plaque?

Answer 28

It can heal or enlarge with a thrombus on the surface.

Question 29

T/F:

You can clearly identify plaque substances on an ultrasound.

Answer 29

False!

You cannot clearly identify plaque substances on ultrasound as fibrous, fatty, hemmorhagic, ulcerated, ect.

Question 30

How can you clearly identify calcification?

Answer 30

It is a bright area with shadow deep to it.

Question 31

What is calcification known to be a sign of?

Answer 31

It is a sign of plaque stability.