Cardiovascular · Year 1 · from Cardiovascular

Case 3: Prinzmetal's (Variant) Angina - Coronary Vasospasm

Patient Presentation

Demographics: 42-year-old female

Chief Complaint: Severe chest pain awakening her from sleep

History of Present Illness: A 42-year-old female with history of migraines presents with recurrent episodes of severe chest pain occurring at rest, typically between 2-5 AM, awakening her from sleep. Episodes last 5-15 minutes and resolve spontaneously or with sublingual nitroglycerin. She denies exertional chest pain. She smokes 1 pack per day. Episodes have increased in frequency over the past month. She was evaluated 6 months ago with a normal stress test.

Physical Examination (during episode):

  • Vital Signs: BP 145/90 mmHg, HR 88 bpm, RR 18/min, SpO2 98% on room air
  • General: Anxious, diaphoretic, in moderate distress
  • Cardiovascular: Regular rhythm, no murmurs
  • Lungs: Clear

Workup

  • ECG during episode:
  • Marked ST elevation in inferior leads (II, III, aVF)
  • ST changes resolved completely within 15 minutes after nitroglycerin
  • ECG at baseline: Normal, no ST changes
  • Troponin: Negative (multiple checks)
  • Echocardiogram: Normal LV function, no wall motion abnormalities
  • Coronary Angiography:
  • No obstructive coronary artery disease
  • Provocation testing with acetylcholine: 90% focal spasm of RCA with chest pain and ST elevation (reproduced symptoms)
  • Spasm relieved with intracoronary nitroglycerin

Diagnosis

Prinzmetal's variant angina (coronary vasospasm) - right coronary artery

Coronary Circulation Correlation:

Normal coronary vascular tone regulation:

  • Vasodilators: Nitric oxide (NO), prostacyclin, adenosine
  • Vasoconstrictors: Endothelin-1, thromboxane A2, serotonin, α-adrenergic
  • Balance maintained by healthy endothelium

Pathophysiology of coronary vasospasm:

  1. Endothelial dysfunction:
  • ↓ NO production or bioavailability
  • ↑ Sensitivity to vasoconstrictors
  1. Smooth muscle hyperreactivity:
  • Enhanced contraction to normal stimuli
  • May involve Rho-kinase pathway
  1. Triggers:
  • Smoking (endothelial damage)
  • Cocaine, amphetamines
  • Circadian variation (early morning surge)
  • Cold exposure
  • Hyperventilation (alkalosis)
  • Acetylcholine (normally causes NO release → vasodilation)

Why rest/nocturnal episodes?

  • Parasympathetic (vagal) tone predominates at rest/sleep
  • Acetylcholine → vasodilation in normal vessels
  • With endothelial dysfunction → direct smooth muscle constriction
  • Early morning: Peak cortisol, catecholamines, platelet aggregability

Coronary blood flow during spasm:

  • Complete spasm → zero flow → transmural ischemia → ST elevation
  • Partial spasm → reduced flow → subendocardial ischemia
  • Transient nature differentiates from thrombotic occlusion

Treatment

  1. Calcium channel blockers (first-line):
  • Diltiazem or verapamil (non-dihydropyridine)
  • Or nifedipine (dihydropyridine)
  • Prevents smooth muscle contraction
  1. Long-acting nitrates:
  • Isosorbide mononitrate nightly
  • Direct coronary vasodilation
  1. Sublingual nitroglycerin PRN for acute episodes
  2. Smoking cessation (essential) - smoking is major trigger
  3. Avoid:
  • Beta-blockers (unopposed α-mediated vasoconstriction)
  • Triptans
  • Cocaine/stimulants
  1. Statins: Improve endothelial function

Clinical Image

Image Description: Coronary angiogram demonstrating focal coronary artery spasm with severe narrowing during provocation testing. The vessel appears nearly completely occluded at the site of spasm, with restoration of normal caliber after administration of nitroglycerin.

Source: Radiopaedia - Coronary vasospasm License: CC BY-NC-SA 3.0 URL: https://radiopaedia.org/cases/prinzmetal-angina

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