Arteriosclerosis

Arteriosclerosis


Hardening and thickening of artery walls
• 3 types
– Atherosclerosis
– Medial Calcification
– Arteriolarsclerosis


Atherosclerosis
• Aorta - common
• Coronary Arteries - common
• Cerebral arteries - basilar and middle cerebral most affected
• Carotid arteries
• Abdominal arteries
– Splenic artery
• Peripheral arteries
• Pulmonary arteries - least common

Pathogenesis of Atherosclerosis

• Intimal injury - injury - markers for LDL.

– Aging

– Hemodynamic factors - turbulence; e.g., HTN

– High cholesterol

• Inflammation

– Monocyte adhesion and migration - turn into macrophages - eats debri = becomes foamy mac

– Oxidation of LDL

– Inflammatory response

monocytes become foamy macrophages after combining with LDL in plasma

Risk Factors

• Not changeable

– Age, Sex, Genetics

• Major reversible

– Smoking** Diabetes, HBP*, Hyperlipidemia

• Minor reversible

– Obesity, Life Style, Personality

*Hypertension
• Increases the severity of atherosclerosis at any age
• Mechanism is mechanical stress on arteries
– Intimal injury
– Medial degeneration

**smoking doubles or triples risk of sudden death


Clinical Effects of Atherosclerosis
• Arterial narrowing

• Bulging plaques
• Calcification
• Hemorrhage 

• Thrombosis

• Acute change in plaque
• – Erosion or ulceration
• – Plaque hemorrhage
• – Plaque rupture
• Vulnerable plaque
• – Moderate luminal narrowing
• – Lipid rich center
• – Thin fibrous cap

• Embolism

• Initiated by 
  rupture or erosion 
  of plaque
• Most from aorta
• – To Kidneys, Pancreas and 
  Spleen
• – To Lower limbs
• Dry gangrene

• Aneurysm - cystic medial degeneration - proteoglycan deposition - weakens walls

1. Atherosclerotic Aneurysm

• • Abdominal aorta belo w renal arteries
• • Iliac arteries
• • Usually over age 60
• • Men > women
• • Clinically significant when > 5 cm. in diameter

  2. Dissecting Aneurysm

• Hypertensive
•  Genetic
• – Marfan Syndrome
• Both types have cystic medial degeneration - 
• Dissection usually starts in arch of aorta

Coronary Artery Artherosclerosis

Myocardial Ischemia

• • Amount of coronary flow
• – Size/narrowing of coronary artery
• – Hypotension
• – Collaterals
• – Arrhythmias
• • Myocardial oxygen requirements
• – Anemia
• – Exercise/Excitement/Fever/Hyperthyroidism

Infarct Location

• Left anterior 

descending: Anterior 

wall, apex and 

septum

• Right: Posterior base 

and posterior septum

• Left Circumflex: 

lateral wall

Sequela of Infarct

• Death from arrhythmia or CHF

• Healing

• Aneurysm

• Rupture

• Postmyocardial syndrome

Sudden Cardiac Death
• Usually not Myocardial Infarct
• Mechanism is cardiac arrhythmia
• Thrombus not usually present
• Severe coronary narrowing
• Previous myocardial infarcts