What are the diagnostic tests and management options for vasospastic angina?

Diagnostic Tests for Vasospastic Angina

Obtain a 12-lead ECG during an angina episode to document transient ST-segment changes (elevation or depression), which is the cornerstone of vasospastic angina diagnosis. 1

Initial Non-Invasive Diagnostic Approach

ECG Documentation During Symptoms

• Capture a 12-lead ECG during chest pain episodes to identify transient ischemic ST-segment changes that occur at rest, typically at normal heart rate 1
• Prinzmetal angina specifically shows transient ST-segment elevation during resting angina attacks, correlating with proximal vessel occlusion 1
• ST-segment changes must resolve with nitrates and/or calcium channel blockers to support the diagnosis 1

Ambulatory ECG Monitoring

• Use 12-lead ambulatory ECG monitoring (Holter) when vasospastic angina is suspected but ECG changes haven't been captured during symptoms 1
• ST-segment shifts occurring at normal heart rate (without tachycardia) strongly support myocardial ischemia from spasm rather than demand ischemia 1
• Extended Holter monitoring for >1 week may be required since most vasospastic attacks are self-limiting and documentation can be challenging 1
• Ambulatory monitoring also assesses treatment efficacy by tracking frequency of vasospastic events 1

Invasive Diagnostic Testing

Coronary Angiography

• Perform invasive coronary angiography or coronary CTA in all patients with characteristic episodic resting angina and documented ST-segment changes to determine the extent of underlying fixed coronary disease 1
• This is a Class I, Level C recommendation from the European Society of Cardiology 1

Intracoronary Provocation Testing

Intracoronary provocation testing with acetylcholine or ergonovine should be performed in patients with normal or non-obstructive coronary arteries on angiography who have a clinical picture consistent with coronary spasm (Class IIa, Level B recommendation) 1

Test Protocol and Interpretation

• Intracoronary acetylcholine or ergonovine are the preferred provocative agents due to low sensitivity of hyperventilation and cold pressor tests 1
• A positive provocation test requires all three components: (1) anginal symptoms, (2) ischemic ECG changes, and (3) severe vasoconstriction of the epicardial vessel 1
• If the test fails to trigger all three components, it should be considered equivocal 1
• Both agents are safe when selectively infused into the left or right coronary artery, with triggered spasm readily controlled by intracoronary nitrates 1

Safety Profile

• Ventricular tachycardia/fibrillation occurs in 3.2% and bradyarrhythmias in 2.7% during provocation testing, similar to rates during spontaneous spasm attacks (7%) 1

Microvascular Assessment

• Intracoronary acetylcholine with ECG monitoring may be considered (Class IIb, Level B) to assess microvascular vasospasm in patients with angiographically normal or moderate stenoses with preserved iwFR/FFR 1
• Angina developing in response to acetylcholine without angiographically evident spasm (with or without ST-segment changes) may indicate microvascular spasm 1
• Guidewire-based coronary flow reserve (CFR) and/or microcirculatory resistance measurements should be considered (Class IIa, Level B) in patients with persistent symptoms but normal or non-obstructive coronary arteries 1

Diagnostic Algorithm

1. First-line: Attempt to capture 12-lead ECG during spontaneous angina episode 1
2. If ECG not captured during symptoms: Deploy 12-lead ambulatory Holter monitoring, potentially for >1 week 1
3. Once transient ST-segment changes documented: Proceed to invasive angiography or coronary CTA to exclude fixed obstructive disease 1
4. If coronary arteries are normal or show non-obstructive lesions: Perform intracoronary provocation testing with acetylcholine or ergonovine to confirm diagnosis and identify spasm location 1
5. If epicardial spasm testing is negative but symptoms persist: Consider microvascular assessment with CFR/microcirculatory resistance measurements or acetylcholine testing for microvascular spasm 1

Common Pitfalls to Avoid

• Do not rely on exercise testing alone, as vasospastic angina typically occurs at rest with preserved exercise capacity 2, 3
• Do not dismiss normal coronary angiography as excluding cardiac causes—proceed to provocation testing in appropriate clinical context 1
• Do not accept incomplete provocation test results—all three criteria (symptoms, ECG changes, and angiographic spasm) must be present for a positive test 1
• Recognize that vasospastic angina is underdiagnosed because provocation testing is rarely performed despite being the gold standard 2, 4, 5