What is the treatment for vasospastic angina?

Treatment of Vasospastic Angina

Calcium channel blockers alone or in combination with long-acting nitrates are the first-line therapy for vasospastic angina to control symptoms and prevent potentially fatal complications. 1

Pathophysiology and Clinical Presentation

Vasospastic angina (also called Prinzmetal or variant angina) is characterized by:

• Chest pain typically occurring at rest, often during late-night or early-morning hours
• Transient ST-segment elevation on ECG during episodes
• Spontaneous resolution or rapid response to nitroglycerin
• Preserved exercise capacity
• Focal coronary spasm (occasionally multifocal or involving multiple vessels)
• May occur with normal coronary arteries, non-obstructive CAD, or obstructive CAD

Smoking is the most prominent risk factor, and a circadian variation exists with most attacks occurring in the early morning 1.

Diagnostic Approach

For patients with suspected vasospastic angina:

• A resting 12-lead ECG during angina episodes is recommended 1
• Coronary angiography (invasive or noninvasive) is recommended in patients with episodic chest pain accompanied by transient ST-elevation to rule out severe obstructive CAD 1
• Provocative testing during invasive coronary angiography may be considered when clinical criteria and non-invasive testing fail to establish the diagnosis 1

Treatment Algorithm

First-Line Therapy:

1. Calcium Channel Blockers (CCBs) 1, 2

   • High-dose CCBs are most effective in decreasing angina incidence, frequency, and duration
   • Success rate of preventing spasm in approximately 90% of patients
   • Consider high doses (up to 480 mg/day verapamil, up to 260 mg/day diltiazem, up to 120 mg/day nifedipine)
   • Second-generation agents like amlodipine are preferred due to better tolerability

2. Add Long-Acting Nitrates if symptoms persist despite CCB therapy 1, 2

   • Effective when combined with CCBs
   • Typical dosages:
     • Isosorbide mononitrate: 20 mg twice daily (standard) or 60-240 mg once daily (slow-release)
     • Isosorbide dinitrate: 5-80 mg 2-3 times daily or 40 mg 1-2 times daily (slow-release)
   • Require a daily nitrate-free interval of 10-12 hours to prevent nitrate tolerance

Additional Therapies:

1. Statin Therapy 1

   • HMG-CoA reductase inhibitors are useful in patients with vasospastic angina

2. Risk Factor Modification 1

   • Smoking cessation is critical as smoking exacerbates coronary vasospasm
   • Address other atherosclerosis risk factors

3. For Refractory Cases 2, 3, 4

   • Consider alpha1-adrenergic receptor antagonists
   • Nicorandil (potassium channel activator) may be useful in patients with refractory vasospastic angina

Important Considerations and Cautions

• Avoid beta-blockers in vasospastic angina as they can precipitate spasm by leaving alpha-mediated vasoconstriction unopposed 2, 4

• Nitrate considerations:

  • Absolute contraindication with phosphodiesterase inhibitors (sildenafil, tadalafil, vardenafil) due to risk of profound hypotension 2
  • Common side effects include headache, hypotension, and flushing 2
  • Monitor blood pressure when initiating therapy or increasing doses 2

• Treatment duration:

  • Spontaneous remission occurs in about half of patients after medical treatment for at least 1 year 1
  • Consider tapering and discontinuing treatment 6-12 months after angina has disappeared 1, 2

Special Populations

• Patients with obstructive CAD and vasospasm:

  • Prognosis is less favorable compared to those with normal coronary arteries 1
  • Follow standard guideline recommendations for secondary prevention 1

• Refractory vasospastic angina:

  • Some patients may not respond adequately to conventional therapy 3
  • May require combination therapy with CCBs, long-acting nitrates, and additional agents 2, 3

By following this evidence-based approach, most patients with vasospastic angina can achieve symptom control and reduce the risk of serious complications such as arrhythmias, syncope, myocardial infarction, and sudden death 1, 5, 6.