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Atherosclerosis

Components of atherosclerosis

• Lipid deposition
• Fibrosis
• Calcifications
• Plaque in the intima of medium and large blood vessels
• Atherosclerosis is the number one cause of cardiac-related death and disability.

Risk Factors

• HTN
• Dyslipidemia
• Smoking
• Diabetes
• Advancing age
• Family history
• Males to Female = 4:1

Clinical Presentation

• No symptoms at all
• Symptoms of ischemia by location
  • Cerebral – cognitive dysfunction
  • Renal – kidney failure
  • Cardiac – Chest pain, MI
  • Intestinal – abdominal pain

Physical Exam findings

A bruit may be present over an artery which is partially occluded.

Labs & Studies

• U/S doppler – blood flow
• Ankle brachial index
  • This compares BP in the upper versus lower extremities. This can be used to determine patency of the arteries for patients with peripheral vascular disease.
• Angiogram
  • Visualize the arteries under x-ray. This is a patient who uploaded his video of his own cardiac cath.

Treatment

• Decrease risk factors
  • Control HTN
  • Better control of lipids
    • A reduction of total cholesterol even in those with diagnosed CAD correlates with reduction in total mortality
  • Quit smoking!!
  • Diabetes control
• Medical treatment
  • Blood thinner
    • Aspirin 81 mg or 325 mg daily
  • Treat dyslipidemia
• Surgery
  • Endarterectomy
  • Stents and balloons

Dyslipidemia

• Low-density lipoprotein (LDL) (lousy)
  • Increased LDL correlates with an increased risk of heart disease.
• High-density lipoprotein (HDL) (happy)
  • Increased HDL correlates with a decreased risk of heart disease.
• Triglycerides
  • An increase in triglycerides is correlated to a an increased risk of heart disease.

Causes and correlations

• Straight out of the Merck Manual “The most important secondary cause in developed countries is a sedentary lifestyle with excessive dietary intake of saturated fat, cholesterol, and trans fats”
• Genetics
• Diabetes
• Liver or kidney disease
• Hypothyroidism
• Alcoholism
• Medications

Clinical presentation

• Asymptomatic
• Routine office visit
  • Routine screening should begin at 35 for men and 45 for women
• Signs of CAD

Physical Exam findings

• Xanthomas are possible, but more than half of people with them have an normal lipid profile.

Labs and Studies

• Serum Lipid Profile (fasting)
• Total Cholesterol
  • Optimal < 200
  • Borderline high 200–239
  • High >240
• HDL
  • Low < 40
  • High > 60
• LDL
  • Optimal < 100
  • Near Optimal 100–129
  • Borderline high 130–159
  • High 160–189
  • Very high >190
• Triglycerides
  • Normal < 150
  • Borderline high 150–199
  • High 200–499
  • Very high >500

Treatment

• Non-pharmacological
  • Diet
    • Reduce dietary fat to 30% and saturated fat to < 10%
    • Mediterranean diet
  • Increase in aerobic exercise helps to increase HDL levels
  • Weight reduction
• Medications
  • 81 mg or 325 mg of Aspirin Daily for those with elevated LDL
  • Statins
    • 3-Hydroxy–3-methylglutaryl coenzyme A reductase inhibitors (HMG-CoA inhibitors)
    • Inhibit rate limiting step in cholesterol production
    • Examples
      • Lovastatin, Pravastatin, Simvastatin, Atorvastatin
    • Most common side effect – Myositis
• Postmenopausal estrogen replacement helps lower LDL and raise HDL
• Niacin is effective but may cause flushing in patients and is not well tolerated
• Bile acid binding resins
  • Cholestyramine, Colestipol,
• Fibric acid derivatives
  • Gemfibrozil, Fenofibrate