Lipids: ASCVD

What is atherosclerosis?

A chronic inflammatory disease characterized by the buildup of cholesterol-rich plaques can rupture and trigger blood clot formation

List the steps of atherosclerosis development?

Endothelial dysfunction, LDL accumulation and inflammation, Foam cell formation, Plaque development, Plaque rupture and thrombosis

Explain what happens in endothelial dysfunction.

The inner lining of the artery becomes dysfunctional, making it easier for LDL particles to enter and become retained in the arterial wall

Explain what happens LDL accumulation and inflammation occurs.

Retained LDL can become modified, triggering an inflammatory response that attracts immune cells

Explain what happens when foam cells form?

Macrophages engulf modified LDL, become foam cells, and accumulate to form fatty streaks

Explain what happens when plaque develops?

Lipids, inflammatory cells, and fibrous tissue accumulate, forming a plaque with a lipid-rich core and fibrous cap

Explain what happens when the plaque ruptures and thrombosis occurs?

A plaque may rupture, exposing material that triggers platelet activation and blood clot formation

What is endothelium and what does it do?

It is the thin layer of cells lining the inside of blood vessels, it helps regulate blood flow and protects the vessel wall

Elevated LDL-C, HTN, Smoking, and diabetes can damage or impair endothelial function; what happens when the endothelial becomes dysfunctional?

LDL particles can enter and become trapped within the arterial wall

LDL isn’t supposed to accumulate inside arterial walls. When it does it can promote inflammation. How does the immune system respond?

By recruiting monocytes, a type of white blood cell, which enter the arterial wall and become macrophages.

What are macrophages and how do they affect atherosclerosis?

Cells that engulf foreign material and cellular debris. In atherosclerosis, they take up modified LDL particles

How do foam cells form?

Cholesterol accumulating inside the macrophages

What happens when foam cells accumulate in the arterial wall? What sign does it symbol?

They form early lesions called fatty streaks, which are the earliest visible signs of atherosclerosis.

List the memory pathway to summarize how lipoproteins are involved in plaque formation.

LDL trapped in artery —> inflammation —> macrophages engulf LDL —> foam cells —> fatty streaks

Once fatty streaks are formed more cholesterol and inflammatory cells accumulate, smooth muscle cells move into the area and help produce connective tissue. What does this tissue form? What does it do?

A Fibrous cap, which covers the buildup of cholesterol and dead cells

Plaque has two main parts; the inside and outside. Explain them.

Inside is a lipid-rich core containing cholesterol and dead cells. Outside is a fibrous cap that covers the core and separates it from circulating blood

As the plaque grows, what does it do to the artery?

It narrows the artery, aka the lumen making it harder for the blood to flow through

If the lumen becomes too narrow, tissues may not receive enough oxygen-rich blood, what is this called?

Ischemia

What are the 2 types of plaques?

Stable and Vulnerable plaque

What are the characteristics of stable plaque?

Has a thicker fibrous cap, less inflammatory activity, lower tendency to rupture, and may cause slow arterial narrowing and reduced blood flow

What are the characteristics of vulnerable plaque?

Has a thin fibrous cap, large lipid-rich or necrotic core, greater inflammatory activity, and more likely to rupture

Vulnerable plaque is dangerous. Why?

It can weaken the fibrous cap, making it more likely to rupture

Does plaque have to cause severe arterial narrowing before it ruptures?

No

When a plaque rupture occurs, the material inside the plaque becomes exposed to circulating blood. The body responds as though there has been an injury. List what happens.

Platelets become activated —> they begin to aggregate —> the coagulation contributes to clot formation —> a thrombus forms at the site of the disruption —> partially or completely block blood flow

A thrombus forms in the coronary artery. What happens?

The clot blocks blood flow to the heart muscle, which can cause a myocardial infarction

A thrombus forms in the Cerebral artery. What happens?

It blocks the blood flow to part of the brain which can cause a ischemic stroke

A thrombus forms in the peripheral artery. What happens?

It causes reduced blood flow to the extremities which can cause limb ischemia

What is a thrombus?

A blood clot that can form after plaque rupture and obstruct blood flow

Why is the timeline important with Atherosclerosis?

Atherosclerosis doesn’t develop overnight. It’s a progressive disease.

What happens when arterial walls are exposed to elevated concentrations of LDL particles?

The more opportunity for cholesterol to accumulate

List the benefits of lowering LDL-C.

Slows the progression of atherosclerosis, helps stabilize existing plaques, reduces the likelihood of cardiovascular events

When triglycerides are elevated, the patient is more at risk for what? Atherosclerosis is not involved in this because plaque formation is not required.

Acute pancreatitis

Is atherosclerosis only limited to the heart?

No it can affect arteries throughout the body

Define coronary artery disease (CAD)?

Atherosclerosis plaque develops in the coronary arteries which reduces blood flow to the heart muscle.

A patient has chest pressure when walking upstairs because the heart requires more oxygen during physical activity what are they experiencing? Explain what it is?

Angina, chest discomfort caused by insufficient oxygen delivery to the heart muscle

What happens during an ischemic stroke?

Plaque or a blood clot blocks blood flow to part of the brain and brain tissue becomes damaged or dies

Explain what a MI is?

a heart attack in which part of the heart muscle becomes injured and dies because of inadequate blood flow

What is a transient ischemic attack (TIA) ? What happens with the symptoms?

A temporary episode of neurological dysfunction caused by reduced blood flow without an active infarction. Symptoms may resemble a stroke but resolve.

How and where does peripheral artery disease (PAD) occur?

Occurs when atherosclerosisi affects arteries supplying blood to the extremities, most commonly in the legs.

A patient develops calf pain after walking two blocks. When they stop and rest, the pain improves. This is a symptom of PAD. What is it called?

Intermittent claudication

Is atherosclerosis a systemic vascular disease?

Yes

What does clinical ASCVD mean?

When atherosclerosis has already caused a clinically recognized cardiovascular problem within the patient.

Define the difference between subclinical and clinical ASCVD. Patient A: subclinical Patient: Clinical.

Patient A has a risk factor for ASCVD. Patient B already has ASCVD.

Is every stroke or CVD condition caused by atherosclerosis? Give an example.

No, a hemorrhagic stroke is caused by bleeding not an atherosclerosis blockage.

What are some conditions that count as clinical ASCVD?

CAD, CVD, PAD

Define primary prevention of ASCVD?

Preventing the first ASCVD event in someone without clinical ASCVD.

Define secondary prevention of ASCVD?

Preventing additional ASCVD events in someone who already has clinical ASCVD.