What is the treatment for variant angina (Prinzmetal’s angina)?

Treatment of Variant Angina (Prinzmetal's Angina)

The first-line treatment for variant angina consists of calcium channel blockers and nitrates, which should be used in combination for optimal management of coronary vasospasm. 1

Pathophysiology and Mechanism

Variant angina is characterized by:

• Transient coronary artery spasm causing temporary ST-segment elevation
• Episodes typically occurring at rest, often in the early morning hours
• Underlying endothelial dysfunction exposing medial smooth muscle to vasoconstrictors
• Spasm that can occur in angiographically normal or diseased vessels

Pharmacological Management

First-Line Therapy

1. Calcium Channel Blockers

   • Most effective class of medications for variant angina 2, 1
   • Mechanism: Inhibit calcium influx into vascular smooth muscle cells, preventing vasospasm
   • Options:
     • Amlodipine: FDA-approved specifically for vasospastic angina 3
       • Dosage: 5-10 mg once daily
       • Demonstrated to decrease angina attacks by approximately 4/week compared to placebo 3
     • Verapamil: Effective but has lower bioavailability due to first-pass effect 4
     • Diltiazem: Alternative option with fewer side effects than nifedipine

2. Nitrates

   • Complementary to calcium channel blockers 2, 1
   • Mechanism: Direct vasodilation through nitric oxide release
   • Options:
     • Short-acting: Sublingual nitroglycerin for acute attacks
     • Long-acting: Isosorbide dinitrate or mononitrate for prevention

Combination Therapy

• For patients with refractory symptoms, combination of calcium channel blockers and long-acting nitrates is recommended 1, 4
• Different classes of calcium channel blockers may be combined in resistant cases

Medications to Avoid

• Beta-blockers: Generally contraindicated as they may worsen coronary vasospasm by leaving alpha-mediated vasoconstriction unopposed 1, 5
• High-dose aspirin: May inhibit prostacyclin production and potentially worsen vasospasm 5

Risk Factor Modification

• Smoking cessation: Critical as smoking is a major trigger for coronary vasospasm 1
• Avoidance of triggers:
  • Cold exposure
  • Emotional stress
  • Hyperventilation
  • Alcohol consumption
  • Cocaine and amphetamine use

Interventional Management

• Percutaneous coronary intervention (PCI): May be considered in patients with chest pain, transient ST-segment elevation, and significant coronary artery stenosis (Class IIb recommendation) 2, 1
• Surgical revascularization with plexectomy has shown benefit in selected cases with spasm superimposed on atherosclerotic lesions 6

Diagnostic Approach

1. Documentation of ST-segment elevation during chest pain that resolves when pain abates
2. Coronary angiography recommended in patients with episodic chest pain accompanied by transient ST-segment elevation
3. Provocative testing may be considered in patients without documented ST-segment elevation during pain (contraindicated in patients with high-grade obstructive stenosis)

Monitoring and Follow-up

• Regular assessment of symptom frequency and severity
• ECG monitoring during symptomatic episodes when possible
• Adjustment of medication doses based on clinical response
• Long-term follow-up due to risk of serious complications including myocardial infarction, high-degree AV block, life-threatening ventricular arrhythmias, and sudden death

Prognosis

• Generally good when there is no significant coronary artery stenosis
• When associated with coronary atherosclerosis, prognosis is determined by the severity of the underlying disease 1

Variant angina requires prompt diagnosis and aggressive treatment with calcium channel blockers and nitrates to prevent potentially life-threatening complications. The treatment approach should focus on symptom control, prevention of attacks, and management of any underlying coronary artery disease.