• Clinical science

Coronary artery disease (Coronary heart disease…)


Coronary heart disease (CHD) refers to a mismatch between myocardial oxygen supply and demand. Atherosclerosis is the most important cause. Atherosclerotic changes in coronary vessel walls lead to a narrowing of the lumen and prevent vessels from dilating. As a result, an increase in oxygen demand (e.g., during physical activity) can no longer be satisfied and/or myocardial perfusion at rest is insufficient. Acute retrosternal chest pain (angina) is the cardinal symptom of CHD. Other symptoms include dyspnea, dizziness, anxiety and nausea. If ischemia is severe, myocardial infarction can occur. Coronary heart disease is diagnosed via a cardiac stress test (possibly provoking symptoms and instrumental findings) and/or coronary catheterization (e.g., measurement of coronary blood flow). Management of CHD involves primary and secondary prevention of atherosclerosis (e.g., weight reduction), antianginal treatment (e.g., beta blockers) and, in some cases, revascularization (e.g., PCTA).

This article provides a basic overview of coronary heart disease and stable angina. Atherosclerosis and acute coronary syndrome (including myocardial infarction) are discussed in separate articles.


  • Lifetime risk of coronary heart disease
    • Age 40: 49% in men and 32% in women
    • Age 75: 35% in men and 24% in women
  • Cardiovascular disease is the leading cause of death in the US and the world.


Epidemiological data refers to the US, unless otherwise specified.




Plaque formation and coronary artery stenosis

  • For plaque formation, see pathogenesis of atherosclerosis.
  • Stable atherosclerotic plaque vascular stenosis → increased resistance to blood flow in the coronary arteries decreased myocardial blood flow → oxygen supply-demand mismatch → myocardial ischemia
  • The extent of coronary stenosis determines the severity of the oxygen supply-demand mismatch and, thus, the severity of myocardial ischemia.
  • Severe ischemia results in myocardial infarction (see acute coronary syndrome for details).
  • Coronary flow reserve (CFR): the difference between maximum coronary blood flow and coronary flow at rest; a measure of the ability of the coronary capillaries to dilate and increase blood flow to the myocardium.
    • In healthy individuals, the CFR can be up to 4 times higher on exertion than at rest.
    • CFR is reduced in individuals with CAD due to vascular stenosis and reduced vascular compliance.

Myocardial oxygen supply-demand mismatch

An increased heart rate reduces oxygen supply and increases oxygen demand!

Effect of vascular stenosis on resistance to blood flow

  • The resistance to blood flow within the coronary arteries is calculated using the Poiseuille equation: R = 8Lη/(πr4), where R = resistance to flow, L = length of the vessel, η = viscosity of blood, and r = radius of the vessel.
  • Provided the length of the vessel and viscosity of blood remain constant, the degree of resistance can be calculated using the simplified formula: R 1/r4

Vascular stenosis increases vascular resistance significantly! For example, a 50% reduction in radius results in a 16-fold increase in resistance: R ≈ 1/(0.5 x r)4 = [1/(0.5 x r)]4 = (2/r)4 = 16/r4

Myocardial ischemia

Coronary steal syndrome

Coronary steal syndrome should not be confused with coronary-subclavian steal syndrome! (see subclavian steal syndrome for more information)

Chronic ischemic heart disease

Progressive heart failure that occurs after many years of chronic ischemic damage to the myocardium.


Clinical features


  • Typically retrosternal chest pain or pressure
    • Pain can also radiate to left arm, neck, jaw, epigastric region, or back.
    • Pain does not depend on body position or respiration
    • No chest wall tenderness
    • Angina may be absent, particularly in younger patients
    • Often gradual progression
    • Can also present as gastrointestinal discomfort
  • Dyspnea
  • Dizziness, palpitations
  • Restlessness, anxiety
  • Autonomic symptoms (e.g., diaphoresis, nausea, vomiting, syncope)

Stable angina

  • Symptoms are reproducible/predictable
  • Complaints often subside within minutes; , with rest or after administration of nitroglycerin
  • Common triggers
    • Mental or physical stress
    • Exposure to cold

Unstable angina

  • Symptoms are not reproducible/predictable
  • Usually occurs at rest or with minimal exertion and is usually not relieved by rest or nitroglycerin
  • Every new-onset angina
  • Severe, persistent, and/or worsening angina (crescendo angina)
  • Increasing intensity, frequency, or duration in a patient with a known stable angina

Unstable angina is a form of acute coronary syndrome and may progress to myocardial infarction. Most patients with CHD first become symptomatic with acute myocardial infarction or sudden cardiac death!

Subtypes and variants

Vasospastic angina

  • Description:
    • Angina caused by transient coronary spasms (usually occurring close to areas of coronary stenosis)
    • Unrelated to exertion and may even occur at rest (classically at night)
  • Etiology: e.g., cigarette smoking, use of stimulants (e.g., cocaine, amphetamines) or sumatriptan, alcohol, stress, hyperventilation, exposure to cold
  • Epidemiology: average onset around 50 years
  • Diagnostics
    • Reversible ST elevation on ECG
    • No troponin I or T level elevations on serial measurements
    • Coronary spasms on angiography confirm the diagnosis
  • Treatment
  • Prognosis:
    • The five-year survival rate is > 90% (with treatment).
      • Persistence of symptoms is common.



Patient history and physical exam

  • History of recurrent angina episodes
  • Signs of atherosclerotic vessel disease (e.g., absent foot pulses, carotid bruit) → see also physical exam in cardiology

Resting ECG

Cardiac stress test

Cardiac stress tests are generally most useful in patients with an intermediate pretest probability of coronary artery disease.

Choosing the most appropriate provocation and detection methods

  • Provocation
    • Able to exercise (and no contraindications for exercise testing): exercise stress test
    • Unable to exercise (and no contraindications to pharmacologic testing): pharmacologic stress test
  • Detection
    • Resting ECG can be interpreted: ECG
    • Resting ECG cannot be interpreted: imaging
  • Example: In a 75-year-old patient with acute aortic dissection, exercise testing would be contraindicated. If he also has atrial fibrillation, imaging would be indicated to monitor the test. Therefore, a pharmacologic stress test with either echocardiography or scintigraphy would be indicated.

Provocation methods

Both types of stress test can be used with ECG, echocardiography, and/or myocardial perfusion imaging. Clinical features, blood pressure, and heart rate are evaluated/recorded simultaneously.


Findings in stress-induced ischemia

Patients with new-onset chest pain, ST segment depression, hypotension or arrhythmias should undergo cardiac catheterization!

Cardiac catheterization

Additional tests


Differential diagnoses

The differential diagnoses listed here are not exhaustive.



Antianginal treatment




  • Prognostic factors
  • Stable angina
    • Annual mortality rate: ∼ 5%
    • 25% of patients will suffer an acute MI within the first 5 years.
    • High-grade stenosis is associated with an unfavorable prognosis.



Prevention of atherosclerosis

Special considerations in coronary heart disease