Atherosclerosis - Cardiovascular

Snapshot
- A 54-year-old man presents to the emergency department 30 minutes after developing crushing sternal chest pain that radiates down the left arm and to the jaw. His symptoms are accompanied by anxiety. Medical history is significant for hypertension, hypercholesterolemia, and type II diabetes mellitus. On physical exam, the patient appears restless and is diaphoretic. An electrocardiogram is performed, which shows ST-segment elevated in leads V1-4. The cardiac catheterization lab is activated and the patient is awaiting stenting after appropriate acute management for acute coronary syndrome.

Introduction
- Definition
  - a pathological process that causes damage to the
    
    aorta
    
    cerebrovasculature
    
    coronary arteries
    
    peripheral arteries
- Epidemiology
  - risk factors
    
    modifiable
    
    hypertension
    
    cigarette smoking
    
    hyperlipidemia
    
    especially hypercholesterolemia
    
    nonmodifiable
    
    age
    
    male gender
    
    family history
    
    genetic abnormalities (e.g., LDL receptor gene mutations)
- Pathophysiology
  - background
    
    LDL transports cholesterol into peripheral tissues and HDL mobilizes cholesterol from the periphery and into the liver for excretion via bile
  - pathogenesis
    
    injury (e.g., smoking, hypertension, and hypercholesterolemia) to the endothelium leads to endothelial dysfunction resulting in
    
    increased vessel permeability
    
    monocyte adhesion and emigration
    
    macrophages become activated within the vessel intima and smooth muscles are recruited
    
    smooth muscle cells migrate to the intima via FGF and PDGF
    
    smooth muscle cells and macrophages engulf lipids (e.g., LDL), forming foam cells, along with recruitment of T lymphocytes forming a fatty streak
    
    smooth muscle cells proliferate and there is deposition of the extracellular matrix, resulting in the fatty streak becoming a fibrofatty atheroma
    
    slow forming plaques allow for the formation of collateral circulation
  - location
    
    abdominal aorta > coronary artery > popliteal artery > carotid artery

Presentation
- Symptoms
  - angina
    
    if > 75% obstruction
    
    myocardial demand ischemia
    
    type of stable angina where individuals with known atherosclerotic coronary disease experience relative myocardial ischemia during episodes of high metabolic demand
    
    subendocardial vessels are susceptible to ischemia during systole due to high resistance and systolic back flow from endocardial to epicardial vessels
    
    left ventricular subendocardial muscle most likely due to left coronary vessel systolic compression
    
    supply/demand mismatch can cause anginal pain and ischemic changes on EKG
  - claudication
  - can be asymptomatic

Complications
- Aneurysms
- Myocardial infarction
- Ischemic stroke
- Peripheral vascular disease
- Atheromatous plaque disruption can result in thrombosis
  - thrombus fragments can break off and result in an embolism

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T