Cardiovascular Disease

Question 1

CVDs

Answer 1

• Coronary heart disease
• Cerebrovascular disease
• Peripheral arterial disease
• Rheumatic heart disease
• Congenital heart disease
• Deep vein thrombosis and pulmonary embolism

Question 2

Risk factors

Answer 2

• Due to levels of circulating lipids
• Uncontrollable genetic background but modifiable lifestyle
  
  • Blood lipids
    - Lead to atherosclerosis
    - HDL-C vs. LDL-C
  • Diabetes mellitus
    
    • metabolic disorder contribute to development of atherosclerosis

Question 3

Controllable vs Not controllable risk factors

Answer 3

Not controllable:
- Sex
- Age
- Family history
Controllable:
- Smoking (endothelial cell damage)
- Obesity
- Sedentary lifestyle
- Untreated hypertension
- Untreated cholesterol
- Stress (too much SNS activation)

Question 4

Atherosclerosis

Answer 4

• Build up of fatty material
  
  • Mainly cholesterol under inner lining of arteries
• Plaque can cause a thrombus (blood clot) to form
• Can dislodge and circulate as a large clot (thromboembolism) -> prevent blood flow into tissues

Question 5

Normal arterial wall

Answer 5

• Endothelial cell (has tight junctions to prevent leakage)
• Elastic connective tissue
• Smooth muscle cells

Question 6

Fatty streak

Answer 6

• LDL cholesterol accumulates
• Macrophages
• Smooth muscle cells
  
  • Move into sub endothelial cell portion to heal lesion
  • Move into neointima

Question 7

Stable fibrous plaque

Answer 7

• Lipid core accumulates
  
  • More lipids deposit into neointima
• Fibrous scar tissue
• Smooth muscle cells
• Calcifications deposited within plaque
• Macrophages move inside vessel wall to help repair tissue
  
  • Ingest and oxidize cholesterol -> enhances state and progression of disease
• Macrophages turn into foam cells

Question 8

Vulnerable plaque

Answer 8

• Platelets
• Macrophages
• Areas of weakness cause force to rip apart vulnerable plaque -> can rupture

Question 9

What happens when a plaque ruptures

Answer 9

• Unstable plaque has no thick fibrous cap -> suspectible to rupture
• Rupture occurs usually along margins of plaque
• Platelets help repair, clotting occlude vessel
• Blood clot can grow and block artery

Question 10

Ischemic heart disease

Answer 10

• An imbalance between supply of oxygen and myocardial demand resulting in myocardial ischemia
• Lesions that occur at higher branch have larger risk area

Question 11

Manifestations of ischemic heart disease

Answer 11

• Asymptomatic
• Stable angina pectoris (periodic chest pains -> can be relieved by nitroglycerin to open blood vessels and restore blood flow)
• Myocardial infarction (complete lack of blood flow)
• Arrhythmia
• Heart failure
• Sudden death

Question 12

Acute Myocardial Infarction: Diagnosis

Answer 12

• Typical chest pain
• Myocardial enzyme elevation
  
  • Creatine kinase (CK-MB)
  • Troponin
• Electrocardiographic changes
  
  • ST elevation

Question 13

Treatment

Answer 13

• Rest, oxygen, analgesia (prevent platelet from adhering and causing more damage through clots), aspirin
• Thrombolysis (lyse clots with thrombosis)
• Primary angioplasty (thread balloon and expand to open lumen and allow blood to flow back to affected tissue)
• Beta-blockers (lowers blood pressure)
• ACE inhibitors (allow heart to work less strenuously against high after load in arterial vessels)

Question 14

Heart failure

Answer 14

• Cardiac output is inadequate
• Causes: heart disease, hypertension, electrolyte imbalance
• Digitalis increases contractility of heart muscle
• Diuretics lower blood volume
• Nitroglycerin is a vasodilator
• Goal is to make heart work more efficiently and reduce stress on heart

Question 15

Angioplasty (Percutaneous Coronary Intervention)

Answer 15

• Before: blood constrained through blockage, moves through small lumen size due to atherosclerotic plaque blocker
• After: vessel more open, blood flow restored

Question 16

Variations in blood pressure

Answer 16

• Blood pressure cycles over 24 hour period
• Extrinsic factors:
  
  • Age
  • Sex
  • Weight
  • Race
  • Mood
  • Posture
  • Socioeconomic status
  • Physical activity

Question 17

Alterations in blood pressure

Answer 17

• Hypertension: sustained, elevated arterial pressure of 140/90 or higher
  
  • Transient elevations are normal and can be caused by fever, physical exertion, and emotional upset
  • Chronic elevation is a major cause of heart failure, vascular disease, renal failure, and stroke
• Hypotension: low BP in which systolic pressure is below 100 mmHg

Question 18

Hypertension: classification

Answer 18

• Essential: causes unknown, yet account for 90% of cases
• Secondary: results from known disease processes that affect blood flow, damage to tissue that result in release of vasoactive chemicals, damage to SNS

Question 19

Carotid and Baroreceptors adapt

Answer 19

• In persistent high BP, baroreceptors think its normal -> stop firing to decrease BP -> pressure remain elevated

Question 20

Consequences of hypertension

Answer 20

• Damage cerebral blood vessels and lead to stroke: either clot or hemorrhage
• Increased cardiac load -> hypertrophy, harder to eject blood if peripheral resistance is high, more work on heart
• Contribute to atherosclerosis
• Pressure imbalances

Question 21

Hypotension

Answer 21

• Orthostatic hypotension: temporary low BP and dizziness when suddenly rising from sitting or reclining position
• Chronic hypotension: hint of poor nutrition, warning sign for Addison’s disease(adrenal cortex defect)
• Acute hypotension: important sign of circulatory shock, threat to patients undergoing surgery and those in intensive care units