Prinzmetal's Angina
Prinzmetal's angina is a distinct syndrome characterized by episodes of transient acute myocardial ischemia due to coronary artery vasospasm, presenting with or without chest pain and associated with transient ST-segment elevation that resolves spontaneously or after nitroglycerin administration. 1
Clinical Characteristics
- Episodes typically occur at rest, often during the night or early morning
- Affects approximately 0.5-1% of patients admitted to hospitals with angina 2
- More common in younger women who may lack traditional cardiovascular risk factors (except smoking) 3
- Associated with other vasospastic disorders like Raynaud's phenomenon and migraine headaches 3
- Demonstrates a waxing and waning pattern with periods of frequent daily episodes followed by symptom-free intervals 2
Pathophysiology
- Caused by focal coronary artery vasospasm that can occur in normal or diseased vessels
- Underlying mechanism involves local hyperreactivity of coronary smooth muscle to various constrictor stimuli:
- Endothelium-derived factors
- Platelet-derived vasoactive substances
- Variations in autonomic tone 2
- Endothelial dysfunction is considered primarily responsible 3
Diagnosis
- Documentation of transient ST-segment elevation during chest pain episodes that resolves when pain subsides is crucial 1
- Coronary angiography is recommended in patients with episodic chest pain accompanied by transient ST-segment elevation 1
- ECG monitoring during episodes and Holter recording can identify ischemic episodes without significant heart rate changes, suggesting primary reduction in oxygen supply 2
- Exercise stress testing is not valuable for diagnosis as this is not a demand-induced condition 3
- Provocative testing with ergonovine may be considered when ST-segment elevation is not documented during pain episodes 1
Complications
- Life-threatening arrhythmias occur in approximately 25% of cases 4
- Potential complications include:
Treatment
First-line Therapy
- High-dose calcium channel blockers are the cornerstone of treatment:
Additional Therapy
- Long-acting nitrates may be added if response to calcium channel blockers is inadequate
- Short-acting nitroglycerin for acute symptom relief
- Consider adding a second calcium channel blocker from a different class for refractory cases
- α-receptor blockers or nicorandil (potassium channel activator) may benefit patients not responding to standard therapy 1
Contraindicated Medications
- Beta-blockers are generally contraindicated as they may worsen vasospasm 1, 3
- Large doses of aspirin should be avoided 3
Lifestyle Modifications
- Smoking cessation is critical as smoking is a major trigger for coronary vasospasm 1
- Avoid known triggers:
- Cold exposure
- Emotional stress
- Hyperventilation
- Alcohol consumption
- Cocaine and amphetamine use 1
Prognosis
- Generally excellent with appropriate medical therapy, especially in patients with normal or near-normal coronary arteries (5-year survival rates of 89-97%) 1
- Worse prognosis in patients with coronary vasospasm superimposed on fixed obstructive coronary artery disease 1
- Consider tapering and discontinuing treatment 6-12 months after angina has disappeared, as spontaneous remission occurs in about half of patients 1
- Long-term follow-up is necessary due to the risk of serious complications 1
Prinzmetal's angina represents a distinct clinical entity that requires specific diagnostic approaches and treatment strategies different from typical exertional angina. Early recognition and appropriate management are essential to prevent potentially life-threatening complications.