CORONARY ARTERY DISEASE

Question 1

Definition (2)

Answer 1

Insufficient perfusion of the coronary arteries due to:
1- Decreased supply:
- Mechanical: atheroma, thrombosis, spasm, embolus, arteritis
- Decreased blood flow: anemia, carboxy Hb, hypotension
2- OR Increased demand:
- Increased cardiac output: HTN
- Hypertrophy from AS, HTN, etc

Most common cause: obstruction (coronary atherosclerosis)

Question 2

Initial endothelial injury/dysfunction triggers atherogenesis, due to: (5)

Answer 2

Mechanical sheer stress (HTN), Biochemical (high LDL, DM), Immunological (free radicals), Inflammation (infection), Genetic alteration

Question 3

Pathophysiology (3)

Answer 3

• Increased permeability of endothelium to oxidized lipoproteins —> accumulation —> taken up by macrophages —> lipid-laden foam cells (seen as fatty streaks macroscopically)
• Progressed within Intracellular lipids —> transitional plaque
• Monocytes, macrophages, and damaged endothelium release cytokines (PDGF, TGF-B) —> accumulation of macrophages + smooth muscle cell migration and proliferation —> collagen produced by smooth muscle cells —> plaque formation

Question 4

Plaque (2)

Answer 4

• Lipid core (fat deposits, foam cells, lymphocytes, phagocytes, smooth muscle cells)
• Fibrous cap (smooth muscle and collagen)

Question 5

Thrombus may be: (2)

Answer 5

• Adherent to plaque (superficial endothelial injury, endothelial denudation, platelet adhesion)
• Extending into lumen (deep endothelial injury, plaque fissuring, exposed core is thrombogenic, thrombus forms within plaque and expands)

Question 6

Hemodynamically significant stenosis:

Answer 6

Decreased luminal cross sectional area of around 70%

Question 7

Classification of CAD (2)

Answer 7

1- Stable Angina
2- Acute Coronary Syndrome
- Unstable Angina
- Non ST-elevation MI
- ST-elevation MI

Question 8

Risk Factors (13)

Answer 8

• Age (above 45 in men and above 55 in women)
• Male gender
• Family history of premature CAD (1st degree FH in male <55yo or female <65yo)
• Diabetes mellitus
• Hyperlipidemia (esp high LDL)
• Hypertension
• Smoking
• Obesity, less exercise, sedentary
• Hypercoagubility (high fibrinogen, factor 7)
• Homocysteinemia
• Drugs (OCP, COX-2 inhibitors)
• Heavy alcohol, cocaine
• Other atherosclerotic disease:
  
  • Intermittent claudication —> 2-4 times increased risk of CAD, CVA, HF
  • MI —> 3-6 times increased risk of CVA, HF
  • CVA —> 2-4 times increased risk of MI, HF