Heart
Ischemic heart disease
Atherosclerotic coronary artery disease

Author: R. Amita, M.D. (see Authors page)

Revised: 19 March 2018, last major update December 2014

Copyright: (c) 2014-2018, PathologyOutlines.com, Inc.

PubMed Search: Atherosclerotic coronary artery disease [title]

Cite this page: Amita, R. Atherosclerotic coronary artery disease. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/heartatheroscleroticCAD.html. Accessed July 23rd, 2018.
Definition / general
  • Atherosclerosis is a chronic vascular disease affecting large and medium sized elastic and muscular arteries, characterized by accumulation within the intima of inflammatory cells, smooth muscle cells, lipid, connective tissue
Pathophysiology
  • Various theories for its origin:
    • Insudation Theory: critical events in atherosclerosis center on the focal accumulation of fat in the vessel wall; lipid in these lesions may derive from plasma lipoproteins
    • Encrustation Theory: mural platelet and thrombi formation is initial event in atherogenesis
    • Inflammation and repair / reaction to injury theory: by Russell Ross and John Glomset
      • Endothelial dysfunction compromises the integrity of the endothelial barrier to macromolecules and leukocyte adhesion molecules on the surface endothelial cells are activated to promote the infiltration of macrophages into the subendothelium
Diagrams / tables

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Risk factors for atherosclerosis

Etiology / Risk factors
  • Genetic and environmental:
    • Hypertension
    • Serum cholesterol level: seems to be most important determinant of geographical differences in incidence of atherosclerotic coronary artery disease
    • Cigarette smoking
    • Diabetes mellitus
    • Increasing age and male gender
    • Physical inactivity and stressful life patterns
    • Homocysteine: results in premature and severe atherosclerosis; homocysteine is toxic to endothelial cells and inhibits several anticoagulant mechanisms in endothelial cells
      • Inhibits (a) thrombomodulin on endothelial cell surface, (b) antithrombin III binding activity of heparan sulfate proteoglycan, (c) binding of tissue plasminogen activator, (d) ecto-ADPase activity on endothelial cell surface which promotes the aggregation of platelets
    • C-Reactive protein and inflammation biomarkers: the presence of CRP in atherosclerotic plaque tissue suggests that systemic inflammation may indeed contribute to atherogenesis
      • Another inflammatory protein under study is serum amyloid A (SAA)
      • Other proteins associated with inflammation, such as leukocyte adhesion molecules and fibrinogen are considered to be biomarkers of disease
Clinical features
  • Chest pain, shortness of breath, weakness, tiredness, reduced exertional capacity
  • Dizziness, palpitations, leg swelling, weight gain
  • Symptoms related to risk factors
Laboratory
  • Complete blood count (CBC), lipid profile, thyroid function tests
  • Blood glucose and hemoglobin A1C, CRP levels
Case reports
Complications
  • Ischemic heart disease, stroke, gangrene of extremities
Gross description
  • Characteristic lesion of atherosclerosis is the fibroinflammatory lipid plaque
  • Simple plaques are elevated, pale yellow, smooth surfaced lesions
  • They are focal in distribution and irregular in shape but have well defined borders
  • A plaque is often eccentric; i.e. it occupies only part of the circumference of the lumen
Gross images

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Yellow lipid plaques

Microscopic (histologic) description
  • Fatty Streak: flat or slightly elevated yellow lesion that contains cells with intracellular accumulation of lipids (foam cells)
  • Intimal Cell Mass:
    • Also considered initial lesion of atherosclerosis
    • Intimal cell masses are white, thickened areas at branch points in arterial tree
    • They contain smooth muscle cells and connective tissue but no lipid
    • The location of these lesions at arterial branch sites correlates well with the location of later atherosclerotic lesions
  • Atheroma:
    • Initially covered by endothelium
    • Area between the lumen and the necrotic core, termed the fibrous cap, contains smooth muscle cells, macrophages, lymphocytes (especially T cells), lipid laden foam cells and connective tissue components
    • Cholesterol crystals and foreign body giant cells may be present within the fibrous tissue and the necrotic areas
    • Blood vessels are rare in healthy coronary arteries but plentiful in atherosclerotic plaques
    • Newly formed vessels are fragile and may rupture, resulting in acute expansion of the plaque due to intraplaque hemorrhage
Microscopic (histologic) images

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Narrowing of lumen

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Foam cells and occasional cholesterol cleft

Additional references