5-6. Atherosclerosis Flashcards by User Unknown

What is atherosclerosis?

A sequential, repetitive process of endothelial damage and sub-endothelial accumulation of fibro-fatty deposites, leading to inflammation

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What does atherosclerosis ultimately lead to?

Vascular occlusion –> limit or completely stop bloodflow

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List the layers of the arterial wall from innermost to outermost.

Tunica intima
Tunica media
Tunica adventitia

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What is the tunica intima composed of?

Endothelium

- Internal elastic lamina

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What is the tunica media composed of?

Smooth muscle cells

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What is the tunica adventitia composed of?

External elastic lamina
Connective tissue
Vaso vasorum

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In what type and size arteries does atherosclerosis most commonly occur?

Medium/large arteries

- Coronary and cerebral arteries

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Describe the process and stages of atherosclerosis?

Fatty streak
Fatty plaque
Fibrous plaque
Complicated plaque

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What % of Americans die from atherosclerosis?

21%

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What is the “clinical threshold” (final step) for atherosclerosis?

Diminished blood flow (occlusion) often due to thrombus (clot) formation

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What can happen if occlusion occurs in the carotid arteries?

Transient ischemia attack
Stroke
Cerebrovascular accident

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What can happen if occlusion occurs in the coronary arteries?

MI
Sudden death
Angina pectoris

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What can happen if occlusion occurs in the peripheral arteries?

Claudication

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What can happen if occlusion occurs in the aorta?

Aneurysm

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Define claudication.

“Angina of the limb”: insufficient blood flow to the limb causes sx of aching, cramping, and burning

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What initiates endothelial damage?

Big 5 risk factors

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List the Big 5 risk factors of atherosclerosis.

Smoking
High blood lipids (LDL cholesterol)
Hypertension
Diabetes
Lack of physical activity

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Other than the big 5 risk factors, what are some dependent risk factors that initiate endothelial damage?

Chronic inflammatory states
Lack of estrogen
Homocysteine
Psychological stress
Obesity

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What is atherogenesis?

Endothelial dysfunction and increased lipoprotein entry

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What is the body’s response to atherogenesis?

INFLAMMATORY:

lipoprotein modification, recruitment of leukocytes
foam cell formation
development of fatty streak
recruitment of smooth muscle cells
formation of fibrous plaque

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When can regression occur during atherosclerosis?

During the early stages (before fibrous plaque)

- When serum cholesterol level is significantly reduced (due to drugs or change in lifestyle)

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What does atherosclerosis regression lead to?

Plaque stabilization (doesn’t shrink much if at all)

What are the clinical benefits of atherosclerosis regression?

Decreased angina sx
Decreased MIs
Decreased total CV mortality

What is the mechanism of atherosclerosis regression?

Decreased blood cholesterol via reverse cholesterol transport by HDL

What are the natural first presentations of coronary artery disease? % of each?

- 20-25% sudden death - 45-55% MI - 20-35% angina

What decreases myocardial O2 supply?

Coronary atherosclerosis (~60% occlusion)

What increases myocardial O2 demand?

Exercise (via increase in RPP)

What occurs if myocardial O2 demand is greater than the supply?

- Angina - Arrhythmia, ST depression - Hypotension - Exercise intolerance - Dyspnea - MI - Sudden death

What is the gold standard of coronary artery disease diagnosis?

Angiogram

What are the non-invasive ways to diagnose coronary artery disease?

- Exercise electrocardiography (GXT, stress test) - Nuclear medicine (myocardial thallium perfusion) - Echocardiography

How does exercise electrocardiography work to diagnose coronary artery disease?

Creates a transient ischemia by increasing myocardial demand beyond the flow limits of the potential atherosclerotic lesion

How does echocardiography work to diagnose coronary artery disease?

Exercise stress is used to precipitate transient ischemia --> heart is visualized echocardiographically, looking for "hypokinetic/akinetic" wall segments

What interventions are used to increase myocardial O2 supply?

Revascularization: - PCTA - CABG - Angioplasty - Angiogenesis

What interventions are used to decrease myocardial O2 demand?

- Meds | - Exercise training

How does angioplasty increase myocardial O2 supply?

Catheter inserted --> tiny ballon inflated --> smooshes fatty plaque up against artery wall --> stent inserted to maintain opening --> increases bloodflow

How does angiogenesis increase myocardial O2 supply?

Catheter inserted --> growth factor capsules implanted in the myocardial wall --> spurs the growth of new blood vessels

What is the goal for physical activity when trying to limit endothelial damage?

- 3-6 hrs/week - 10K steps/day - 150 MetxMins/day - 450-750 MetxMins/week

What is the ideal blood glucose level?

Less than 110 mg/dl

What are the ideal levels for blood lipids?

- LDL less than 130 | - HDL greater than 50

How does medical therapy (drugs) help treat atherosclerosis?

Lowers RPP --> reduces the heart's demand for oxygen at any level of whole body work

What are the agents used to lower RPP?

- Nitrates - Beta blockers - Ca2+ channel blockers - Exercise training

How do nitrates lower RPP?

- Veno and vasodilators - Lowers BP - Lowers wall tension

How do beta blockers lower RPP?

Blocks receptors for catecholamines --> lowers HR & BP

How do Ca2+ blockers lower RPP?

Lowers HR (chronotropy) and contractility (inotropy)

How does exercise training lower RPP?

- Reduces catecholamine release - Lowers HR - Lowers BP

What is a simple, safe intervention to lower platelet "stickiness"?

Micro aspirin treatment

What are the goals of cardiac rehab?

- Rehabilitate the patient to be a fully functional member of society and their family - Decrease the risk of a recurrent cardiac event

What does cardiac rehab NOT do?

- Repair deficits in cardiac function | - Re-establish blood flow

What are the phases of cardiac rehab?

1. Inpatient or acute 2a. Early outpatient or subacute 2b. Progressive conditioning 3. Maintenance

What medications are prescribed as a part of cardiac rehab?

- Aspirin - Lipid lowering agents - Beta blockers - ACE inhibitors

What single disease process accounts for ~1/3 of all deaths in the U.S.?

Atherosclerosis

What is the primary non-pharmaceutical intervention to elevate HDL?

Aerobic exercise

What is the primary non-pharmaceutical intervention to lower LDL? What are additional interventions?

* *Diet intervention - high fiber - regular exercise