Coronary Vasospasm & Angina or MI with Normal Coronary Arteriograms

Key Features

• Precordial chest pain, often occurring at rest during stress or without known precipitant, relieved rapidly by nitrates

• ECG evidence of ischemia during pain, sometimes with ST-segment elevation

• No significant obstruction of major coronary vessels

• Coronary spasm that responds to intracoronary nitroglycerin or calcium channel blockers

Clinical Findings

• Spasm of the large coronary arteries with resulting decreased coronary blood flow

  • May occur spontaneously or induced by exposure to cold, emotional stress, or vasoconstricting medications and substances, such as ergots and cocaine

  • May occur both in normal and in stenosed coronary arteries

• Ischemia may be silent or result in angina pectoris or even infarction

• Prinzmetal (variant) angina

  • Chest pain occurs without the usual precipitating factors and is associated with ST-segment elevation rather than depression

  • The associated ischemia usually results from coronary vasoconstriction

  • It tends to involve the right coronary artery and there may be no fixed stenoses

  • Myocardial ischemia may also occur in patients with normal coronary arteries as a result of disease of the coronary microcirculation or abnormal vascular reactivity

  • Often affects women under 50 years of age

  • Characteristically occurs in the early morning or on awakening from sleep and is associated with arrhythmias or conduction defects

Diagnosis

• Prinzmetal (variant) angina

  • May be diagnosed by challenge with ergonovine (a vasoconstrictor)

  • However, results of ergonovine provocation are not specific and it entails risk

• Patients with chest pain associated with ST-segment elevation should undergo coronary arteriography to determine whether fixed stenotic lesions are present

• Cardiac MRI is recommended in the 2020 European Society of Cardiology (ESC) guidelines to aid in determining the cause of myocardial infarction (MI) without obstructive coronary disease, which is more frequent in women and has been shown to be due to atherosclerosis or ruptured plagues in 80% of cases

Treatment

• If fixed stenotic lesions are present, aggressive medical therapy or revascularization is indicated

• If significant lesions are not seen, there may still be endothelial disruption and plaque rupture

• If spasm is suspected, avoidance of precipitants such as cigarette smoking and cocaine is the top priority

• Treatment of coronary vasospasm episodes generally involves nitrates

• Prophylaxis of episodes can be achieved with both nitrates and calcium channel blockers (including long-acting nifedipine, diltiazem, or amlopidine)

• β-Blockers

  • Can exacerbate coronary vasospasm by allowing unopposed α₁-mediated vasoconstriction

  • May have a role in patients in whom spasm is associated with fixed stenoses