Arterosclerosis

Question 1

What is atherosclerosis ?

Answer 1

Deposition of fat in large elastic arteries and large and medium sized arteries.

Formation of plaque in the arteries leading to stoppage of blood flow

Atherosclerosis is a chronic inflammatory and healing response of the arterial walls to endothelial injury

Question 2

What part of the blood vessel does the atherosclerotic plaque occur?

Answer 2

Tunica initima

Question 3

Classes of risk factors of atherosclerosis?

Answer 3

Non-modifiable and modifiable

Question 4

Non-modifiable risk factors?

Answer 4

Genetics- most independent risk factor (familial hypercholesterolemia )

Age- dominant factor ( btw 40-60 years increases incidence of atherosclerosis by 5 fold

Male gender- increase in incidence after menopause

Question 5

Modifiable risk factors?

Answer 5

Hyperlipidemia
Hypertension
Cigarette smoking
Diabetes mellitus

Question 6

Hypercholesterolemia?

Answer 6

Elevated LDL lipoprotein

Deposition of cholesterol to the peripheral

Found in Diets ( yolks and saturated fats)

HDL moves the cholesterol from the periphery to the liver for excretion in the bile ( protective role)

Question 7

Factors influencing hypercholesterolemia

Answer 7

Obesity and smoking- lowers HDL

Exercise- increases HDL

Diabetes mellitus- induces hypercholesterolemia

Question 8

Endothelial cell injury

Answer 8

Corner stone of the response to injury hypothesis

Question 9

Sequence of event in atherosclerosis

Answer 9

1. Endothelial injury causes increase in vascular permeability, leukocyte adhesion and thrombosis.
2. Inward movement of lipoprotein (LDL) into tunica intima
3. Monocytes adhesion and migration into the tunica intima and transformation into macrophages and then foam cells by combining with oxidized LDL
4. Platelet adhesion
5. Smooth muscle cell recruitment either from tunica media or circulation
6. Smooth muscle cell proliferation, extra cellular matrix production, and T cell. Production of collagen from smooth muscle
7. Lipid accumulation extra cellularly and with macrophages and smooth muscle cells

Question 10

Morphology of atherosclerosis legion

Answer 10

1. Fatty streaks - lipid filled macrophages foamy cells, no blood flow disturbance
2. Atherosclerotic plaque - initial ticketing and lipid accumulation

Mild atherosclerosis- fibrous plaque
Severe atherosclerosis- ulcerated plaque with overlying thrombus

Question 11

Components of atherosclerotic plaque

Answer 11

1. Smooth muscle cells, macrophages, T cells
2. ECM, collagen, elastic fibers, proteoglycans
3. Intracellular and extra cellular lipid

Question 12

Arrangements of atherosclerosis

Answer 12

Fibrous cap
Shoulder
Necrotic core

Question 13

Changes in plaque ?

Answer 13

1. Rupture, ulceration, erosion leading to thrombus formation
2. Organized and incorporation of clot into plaque
3. Hemorrhage into a plaque
4. Athero embolism- microemboli
5. Aneurysm formation- pressure or ischemic atrophy of the media with loss of elastic tissue causing weakness and repture

Question 14

Types of plaque ?

Answer 14

Vulnerable plaque - thin fibrous cap

Stable plaque