2. Epidemiology of ischaemic heart disease

From greek.doctor
  • Leading cause of death in US and the world
  • Higher risk in men than women
  • Rising tendency in developing countries
  • Accounts for nearly 30% of all disability cases
  • Especially affects middle aged population
  • Proposed theories
    • Lipid theory
      • Decreasing blood cholesterol decreases IHD
      • Oxidized LDL enters vessel wall
    • Blood coagulation theory
      • Increased coagulation tendency
      • Evidence:
        • Increased plasma fibrinogen
        • Increased thromboxane A2/prostaglandin ratio
        • Increased lipoprotein(a) (inhibits fibrinolysis)
    • Blood vessel wall theory
      • Collagen increases, elastic fibres decrease
      • Increases microthrombi formation and lipid infiltration
  • Pathomechanism of atherosclerosis
    • Endothelial dysfunction
      • HT
      • Smoking
      • Diabetes
      • High LDL
      • Aging
    • Leukocyte migration into tunica intima
    • Proliferation of smooth muscle cells in tunica intima
    • Oxidized LDL accumulates, macrophages transform into foam cells
    • Foam cells and smooth muscle cells produce collagen -> forms fibrous plaque
    • Inflammation in fibrous plaque weakens the fibrous cap
    • Plaque ruptures, exposing thrombogenic material