20. Common CVDs part 2

Question 1

Risk of stable vs. unstable blockage.

Answer 1

• Stable blockage up to 65% causes a plumbing prob in which you can’t deliver enough blood during exercise
• Unstable blockage of 33-40% can rupture into the lumen of the vessel and trigger a clot –> fatal

Question 2

Describe the progression of atheromas in blood vessels w/ age.

Answer 2

• Progresses slowly, over decades
• Foam cell –> fatty streak –> intermediate lesions –> atheroma –> fibrous plaque –> complicated lesion rupture of unstable cap
• Once fibrous plaque is reached, not reversible

Question 3

What is the effect of risk factors in the progression of atheromas?

Answer 3

Risk factors speed up progression

Question 4

What are foam cells?

Answer 4

Phagocytic white blood cells, usually macrophages, that ingest large volumes of sub-endothelia lipid droplets

Question 5

List the atherogenic effects of smoking.

Answer 5

• Endothelial damage
• Increased platelet adhesion
• Pro-inflammatory
• Arterial wall hypoxia
• Increased LDL oxidation
• Reduced HDL cholesterol
• Increased blood viscosity
• Impaired endothelial-mediated vasodilation

Question 6

What % of circulating blood cholesterol does dietary cholesterol contribute?

Question 7

What are the dietary modulators of plasma cholesterol?

Answer 7

• Increase in dietary saturated (animal) fat
• Increase in excess body fat stores
• Decrease in dietary fiber (esp water soluble)
• Increase in dietary cholesterol

Question 8

What is the normal value for total cholesterol?

Question 9

What is the normal value for HDL cholesterol?

Answer 9

> 40 mg/dl

Question 10

Contrast the structure of LDL and HDL.

Answer 10

• HDL has a large # of lipoproteins and a smaller amount of cholesterol
• LDL is mostly fat and not much protein

Question 11

What is the single best intervention for raising HDL?

Answer 11

Exercise

Question 12

What directly lowers HDL?

Answer 12

Smoking

Question 13

What is LDL mostly controlled by?

Answer 13

Dietary intervention

Question 14

What is HDL’s role in plaque regression?

Answer 14

Reverse cholesterol transport

Question 15

What are the beneficial effects of HDL?

Answer 15

• Anti-inflammatory
• Anti-thrombotic (blood clotting)
• Antioxidant
• Anti-apoptotic (cell death)
• Reverse cholesterol transport

Question 16

List the natural first presentations of coronary artery disease. What % of CAD present this way?

Answer 16

• 15-20% sudden death
• 45-55% myocardial infarction
• 35-40% angina

Question 17

What does a narrowed lumen result in? Blocked lumen?

Answer 17

• Narrowed lumen –> exertional ischemia

- Blocked lumen –> MI or death

Question 18

What is angina? Symptoms?

Answer 18

• Subjective experience of ischemia elicited by exercise or emotional stress
• Vague, aching, squeezing, or burning

Question 19

What is a significant contributor of angina?

Answer 19

Impaired vasodilatory ability

Question 20

What is the benefit of exposing an atheroma by exercise as opposed to waiting?

Answer 20

• Waiting for resting sx reveals 90% stenoses

- Exercise may reveal atheromas as small as 60-65%

Question 21

Stable vs. Unstable plaque.

Answer 21

STABLE:
-small lipid pool
-thick fibrous cap
-preserved lumen
UNSTABLE:
-large lipid pool
-thin fibrous cap
-many inflammatory cells

Question 22

Stable vs. Unstable angina/ischemia

Answer 22

STABLE:
-lumen narrowed by plaque
-inappropriate vasoconstriction
UNSTABLE:
-plaque rupture
-platelet aggregation
-thrombus formation
-unopposed vasoconstriction

Question 23

What is acute coronary syndromes?

Answer 23

Sudden, severe alterations in coronary flow leading to unstable angina and may become acute MIs

Question 24

What causes 90% of acute coronary syndromes?

Answer 24

Rupture of an atherosclerotic plaque, leading to platelet aggregation and formation of a thrombus