Management of Prinzmetal (Variant) Angina
Acute Management
Sublingual or intravenous nitroglycerin is the immediate treatment of choice for acute episodes of Prinzmetal angina, providing rapid reversal of coronary vasospasm within minutes. 1, 2
Administer one sublingual nitroglycerin tablet (0.3-0.4 mg) at the first sign of chest pain, dissolving it under the tongue or in the buccal pouch while the patient rests in a sitting position. 2
Repeat the dose every 5 minutes if pain persists, up to a maximum of 3 tablets over 15 minutes. If symptoms continue after 3 doses or if the pain quality differs from typical episodes, seek immediate medical attention. 2
For refractory cases in the hospital setting, intravenous nitroglycerin (2-10 mg) or intracoronary nitroglycerin during catheterization can be administered. 3
Sublingual nifedipine (5-10 mg) serves as an alternative when sublingual nitrates fail to provide relief. 3
Patients typically experience prompt resolution of both chest pain and ST-segment elevation following nitroglycerin administration, which helps confirm the diagnosis. 4, 1
Preventive Medical Therapy
High-dose calcium channel blockers are the cornerstone of long-term prevention and should be initiated immediately after diagnosis. 1, 5
First-Line Therapy: Calcium Channel Blockers
Start with one of the following calcium channel blockers at high doses: 1
- Verapamil 240-480 mg/day
- Diltiazem 180-360 mg/day
- Nifedipine 60-120 mg/day
- Amlodipine (FDA-approved specifically for vasospastic angina) 6
Calcium channel blockers prevent spasm in approximately 90% of patients and can completely control ischemic attacks in up to 80% of cases. 7, 3
Adjust the medication schedule to match the circadian pattern of spasm episodes, as attacks frequently occur in early morning hours. 4, 7
Second-Line Therapy: Long-Acting Nitrates
Add long-acting nitrates to calcium channel blockers in patients with very active disease or incomplete symptom control on monotherapy. 1, 5
Combination therapy provides additive vasodilation and superior symptom control compared to either agent alone. 1
Critical Contraindication
Beta-blockers are absolutely contraindicated in Prinzmetal angina because they cause unopposed alpha-adrenergic coronary vasoconstriction, precipitating and worsening coronary spasm. 1, 5, 7
- This includes propranolol and all other beta-blocking agents. 7
Essential Non-Pharmacologic Management
Smoking Cessation
Complete and permanent smoking cessation is mandatory, as the majority of Prinzmetal angina patients are current smokers despite having fewer traditional coronary risk factors. 1, 5
Smoking is strongly associated with variant angina and directly contributes to disease activity. 1
Continued smoking significantly impairs therapeutic outcomes and must be addressed as aggressively as pharmacologic therapy. 1
Diagnostic Confirmation and Risk Stratification
Coronary angiography is required to determine whether vasospasm occurs in isolation or is superimposed on obstructive coronary artery disease. 1, 7
Approximately 58% of Prinzmetal angina patients have concurrent fixed obstructive lesions (39% single-vessel, 19% multivessel disease). 1, 7
Patients with vasospasm superimposed on fixed obstructive disease have significantly worse prognosis and require more aggressive medical therapy or consideration of revascularization. 4, 1, 5
Spontaneous coronary spasm frequently develops during angiography, often eliminating the need for pharmacologic provocation testing. 1
Provocative Testing
Intracoronary acetylcholine or ergonovine provocation testing can confirm vasospasm when spontaneous spasm is not observed during angiography. 4
Hyperventilation testing has limited sensitivity and is less reliable than pharmacologic provocation. 4
Long-Term Management Considerations
Continuous therapy is required indefinitely, regardless of symptom status, because variant angina follows a waxing-and-waning pattern with unpredictable periods of activity. 4, 1
Patients may experience numerous daily episodes during active phases, followed by prolonged asymptomatic intervals lasting weeks to months. 4, 1
Do not discontinue therapy during asymptomatic periods, as this increases the risk of life-threatening complications during subsequent active phases. 1
Monitoring for Complications
During active disease phases, patients face significant risk for myocardial infarction, sudden cardiac death, high-grade atrioventricular block, and life-threatening ventricular arrhythmias. 4, 1
Lethal cardiac events occur most frequently in patients who develop complex ventricular tachyarrhythmias or AV block during episodes of transient myocardial ischemia. 4, 1
On optimal medical treatment, the long-term prognosis is generally favorable, with cardiovascular death rate of 0.5% per year and myocardial infarction risk of 1.2% per year. 4
The number of diseased arteries on angiography is the strongest predictor of death or myocardial infarction during follow-up. 4
Common Pitfalls to Avoid
Exercise stress testing is unreliable for diagnosing vasospastic angina and should not be used as a primary diagnostic tool. 1, 7
Results are unpredictable: approximately one-third show ST-elevation, one-third show ST-depression, and one-third show no ECG changes. 1, 7
A normal resting ECG when asymptomatic does not exclude variant angina; diagnosis requires documentation of transient ST-segment elevation during chest pain episodes. 1, 7
Holter monitoring is valuable for identifying ischemic episodes without significant heart rate changes, suggesting primary reduction in oxygen supply (vasoconstriction) rather than increased demand. 4
Avoid large doses of aspirin in pure vasospastic angina without obstructive disease, as it may theoretically worsen vasospasm. 7
For patients not responding completely to calcium channel blockers and nitrates, alpha-receptor blockers have been reported to provide benefit in select cases. 5