Vasospastic Angina

Aka: Vasospastic Angina, Prinzmetal's Angina, Variant Angina, Variant Angina Pectoris, Coronary Artery Vasospasm

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II. Pathophysiology

  1. Focal arterial spasm of a major Coronary Artery
    1. Typically in the absence of high grade Coronary Artery stenosis
  2. Mechanisms
    1. Vascular Smooth Muscle hyperreactivity to Vasoconstrictors
    2. Increased vagal tone
    3. Increased hyperreactivity to sympathetic stimulation
    4. Endothelial dysfunction
  3. Comorbid arterial stenosis
    1. Most arterial lesions are eccentric (75%)
      1. Considerable vasoactivity in most vessels
    2. Vasoconstriction occurs at lesion with Exercise
      1. Paradoxical: vasodilatation would be expected
      2. Occurs due to passive vasodilation down stream
  4. May be associated with other vasospastic conditions
    1. Raynaud's Phenomenon
    2. Migraine Headache

III. Epidemiology

  1. Age
    1. More common under age 50 years old
  2. Race
    1. More common in Japanese patients than in Caucasian
  3. Incidence
    1. Coronary Artery Vasospasm found in 4% of Coronary Artery angiograms in U.S.
      1. United States however has among lowest Incidence of Coronary Artery Vasospasm

IV. Risk Factors

  1. Tobacco Abuse
  2. Cocaine Abuse
    1. See Cocaine-Induced Coronary Vasospasm

V. Symptoms

  1. Recurrent episodic Chest Pain consistent with Angina
    1. Anterior chest discomfort or pressure
    2. Radiates to neck, jaw, arms as with typical Angina
  2. Triggers
    1. Typically occurs at rest without provocation (e.g. without Exercise, not modified by position)
    2. May be triggered by Hyperventilation, Cocaine, hypersympathetic states (e.g. peak Exercise)
  3. Timing
    1. Early morning hours after midnight
  4. Duration
    1. Episodes last 5 to 15 minutes
  5. Characteristics
    1. Gradual onset and resolution
  6. Associated symptoms
    1. Typical Angina related symptoms (Nausea, diaphoresis, Dyspnea)

VI. Labs

  1. Obtain typical labs for chest Pain Evaluation
  2. Serial Troponin
  3. Magnesium

VII. Diagnostics

  1. Electrocardiogram
    1. Normal between episodes
    2. ST Segment Elevation during vasospastic episode
  2. Holter Monitor
    1. May detect episodes of periodic ST Elevation
  3. Stress Testing
    1. Evaluate for severe fixed cardiovascular disease
  4. Coronary Angiography
    1. Consider in most patients with suspected Variant Angina

VIII. Differential Diagnosis

  1. ST Elevation Myocardial Infarction (STEMI)
  2. Unstable Angina
  3. Microvascular Angina
  4. Acute Pericarditis
  5. Stress-Induced Cardiomyopathy (Takotsuba Cardiomyopathy)

IX. Management: Prevention of vasospasm

  1. First-Line measures
    1. Tobacco Cessation
    2. Calcium Channel Blockers
      1. Diltiazem 240 to 360 mg orally daily
      2. Nifedipine
      3. Verapamil
    3. Other measures as indicated
      1. Statins (e.g. Atorvastatin, Simvastatin, Fluvastatin)
      2. Replace Magnesium in Magnesium Deficiency
  2. Second-Line measures
    1. Long-Acting Nitroglycerin
      1. Isosorbide Mononitrate 30-60 mg once daily
      2. Indicated if refractory to Calcium Channel Blockers
      3. Risk of nitrate tolerance (Calcium Channel Blockers are preferred)
  3. Third-Line Measures
    1. Percutaneous Coronary Intervention (PCI)
      1. May be indicated in moderate fixed coronary obstruction
  4. Avoid provocative agents
    1. Limit Aspirin to low dose
      1. Higher dose may predispose to vasospasm
      2. Aspirin 81 mg should be prescribed in atherosclerotic cardiovascular disease
    2. Avoid non-selective Beta Blockers (e.g. Propranolol)
      1. Risk of vasospasm
    3. Avoid other agents associated with vasospasm
      1. Triptans (e.g. Sumatriptan)
      2. 5-Fluorouracil

X. Complications

  1. Myocardial Infarction
    1. Risk of thrombus forming in response to vasospasm
  2. Arrhythmia
    1. Ventricular Tachycardia (left Coronary Artery)
    2. Heart Block (right Coronary Artery)
    3. May present with Syncope to Cardiac Arrest
      1. Consider Implantable Cardioverter-Defibrillator (ICD)

XI. Resources

  1. EMedicine Coronary Artery Vasospasm
    1. http://emedicine.medscape.com/article/153943-overview#showall

XII. References

  1. Pinto, Beltrame, Crea in Saperia (2015) Variant Angina, UpToDate, Wolters Kluwer (accessed 6/13/2015)

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