What is the treatment for a patient with Prinzmetal angina?

Treatment of Prinzmetal Angina

Calcium channel blockers and nitrates are the first-line therapies for Prinzmetal angina, with calcium channel blockers preventing spasm in approximately 90% of patients. 1, 2

First-Line Medical Therapy

Initiate combination therapy with a calcium channel blocker plus long-acting nitrate:

• Calcium channel blockers (nifedipine, diltiazem, or verapamil) are equally effective and should be started immediately 1, 3
• Verapamil is a potent inhibitor of coronary artery spasm and dilates both main coronary arteries and arterioles, making it particularly effective for vasospastic angina 4
• Long-acting nitrates are efficacious but require intermittent administration to prevent tolerance 2
• Both drug classes have Class I recommendation with Level B evidence from ACC/AHA guidelines 5, 1

Critical Medications to AVOID

Beta-blockers are absolutely contraindicated in Prinzmetal angina:

• Beta-blockers cause unopposed alpha-adrenergic vasoconstriction, which precipitates and worsens coronary spasm 1, 2, 6
• When propranolol blocks β-receptors, circulating catecholamines can only bind to α-receptors, resulting in paradoxical coronary vasoconstriction 2
• ACC/AHA guidelines explicitly state beta-blockers should be avoided due to their theoretical adverse potential 1
• Large doses of aspirin are also contraindicated in pure vasospastic angina 7, 6

Refractory Cases

For patients not responding completely to calcium channel blockers and nitrates:

• Escalate to high doses of calcium channel blockers before adding additional agents 2
• Alpha-receptor blockers have been reported as beneficial for incomplete responders 1, 2
• Consider sympathectomy as a therapeutic option for rare patients refractory to maximally tolerated doses of calcium channel blockers 2

Essential Risk Factor Modification

Smoking cessation is mandatory:

• Smoking is a major risk factor for Prinzmetal angina and must be addressed 1
• Patients with atherosclerotic lesions on angiography are considered higher risk and require aggressive risk factor modification 5

Coronary Angiography Considerations

Coronary angiography is usually part of the workup to guide treatment:

• 58% of Prinzmetal angina patients have underlying obstructive coronary disease (39% single-vessel, 19% multivessel) 5, 7
• PCI may be considered in patients with chest pain, transient ST-elevation, and significant coronary stenosis (Class IIb recommendation) 5
• Patients with vasospasm superimposed on fixed obstructive disease have worse prognosis and require more aggressive therapy 1

Monitoring and Long-Term Management

Continue vasodilator therapy indefinitely:

• Monitor for resolution of anginal episodes and ST-segment changes on ECG 1
• Long-term therapy is necessary despite symptom-free intervals, as attacks often occur in clusters with prolonged asymptomatic periods of weeks to months 5, 1
• Maintain calcium channel blockers and nitrates throughout any perioperative period without interruption 7

Common Pitfalls to Avoid

• Do not rely on exercise stress testing for diagnosis or risk stratification—it is unreliable in Prinzmetal angina, as this is a supply (vasospastic) abnormality, not a demand-induced symptom 7, 6
• Do not assume normal resting ECG excludes active disease—attacks typically occur at rest in early morning hours 7
• Do not perform provocative testing if high-grade obstructive stenosis is present on angiography (Class III recommendation) 5, 7
• Do not use beta-blockers even if the patient has concurrent stable angina—the risk of precipitating severe vasospasm outweighs any potential benefit 1, 2, 6