What diagnostic tests and management strategies are used for patients presenting with angina?

Diagnostic Testing for Angina

For patients presenting with angina, begin with a resting 12-lead ECG, basic laboratory tests (CBC, lipid panel, fasting glucose, HbA1c), and resting echocardiography, followed by exercise ECG testing as the first-line stress test for those who can exercise. 1

Initial Basic Testing (Perform in All Patients)

Laboratory Tests:

• Complete blood count, fasting plasma glucose, and HbA1c to identify causes of ischemia and provide prognostic information 1
• Lipid profile including total cholesterol, HDL, LDL, and triglycerides for cardiovascular risk assessment 1
• Cardiac troponins if acute coronary syndrome is suspected 2

Electrocardiography:

• Resting 12-lead ECG to identify prior MI, left ventricular hypertrophy, conduction abnormalities, or ischemic changes 1
• Compare with prior ECGs when available to assess for new changes 2
• For suspected variant (Prinzmetal's) angina: obtain 12-lead ECG during chest pain episodes to document transient ST-segment elevation 3

Echocardiography:

• Resting echocardiography to assess left ventricular function, wall motion abnormalities, and valvular disease 1
• Two-dimensional echocardiogram during chest pain may document transmural ischemia in variant angina 3

Non-Invasive Stress Testing

Exercise ECG Testing (First-Line for Most Patients):

• Exercise ECG is the standard initial stress test for patients with new-onset stable angina who can exercise and have a normal resting ECG 1, 3
• Provides information on exercise capacity, hemodynamic response, and exercise-induced ischemia 1
• Should be performed within 72 hours in low-risk unstable angina patients evaluated outpatient 3
• In hospitalized low-risk patients, test after 8-12 hours symptom-free; intermediate-risk patients after 2-3 days 3

Advanced Stress Imaging (When Exercise ECG Insufficient):

• Stress echocardiography evaluates wall motion abnormalities during stress 1, 3
• Myocardial perfusion imaging (nuclear) assesses perfusion defects during stress with diagnostic accuracy superior to exercise ECG alone 3
• Use stress imaging for patients unable to exercise, those with baseline ECG abnormalities (bundle branch block, LVH, paced rhythm), or when exercise ECG results are equivocal 3
• Pharmacological stress testing (with vasodilators or dobutamine) for patients unable to exercise adequately 3

Invasive Testing

Coronary Angiography Indications:

• Severe symptoms (Canadian Cardiovascular Society class III-IV) despite maximal medical therapy 1
• High-risk findings on non-invasive testing 1
• Known left ventricular dysfunction or unstable symptoms 1
• Suspected variant angina with documented ST-segment elevation to visualize coronary anatomy and assess for underlying stenosis 3
• Special occupational requirements 1

Invasive Functional Testing:

• In persistently symptomatic patients with suspected angina with non-obstructive coronary arteries (ANOCA) or ischemia with non-obstructive coronary arteries (INOCA), invasive coronary functional testing is recommended to identify treatable endotypes 3, 4
• Fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) for intermediate stenoses 3

Specialized Testing for Variant Angina

Diagnostic Approach:

• Continuous 12-lead ECG monitoring (in-hospital or outpatient) to record transient ST-segment elevation during chest pain episodes 3
• Exercise testing may show ST-elevation (one-third), ST-depression (one-third), or no change (one-third); more often positive in early morning 3

Provocative Testing (Rarely Used, High-Risk):

• Reserved for patients with suggestive symptoms not otherwise diagnosed, failed medical therapy, or verification of treatment efficacy 3
• Hyperventilation for 6 minutes in the morning, alone or after exercise 3
• Pharmacological tests with acetylcholine or methacholine during coronary angiography (ergonovine no longer generally available) 3
• Critical caveat: Provocative testing carries risk of prolonged ischemia, MI, or death; should only be performed with ability to visualize coronary arteries and immediately administer intracoronary nitroglycerin 3

Follow-Up Testing

Routine Monitoring:

• Annual fasting lipid profile and fasting glucose 1
• Repeat ECG when medications affecting cardiac conduction are changed or when anginal pattern changes 1
• Repeat stress testing only if significant change in clinical status, not routinely more frequently than every 3 years in stable patients 1

Common Pitfalls to Avoid

• Do not dismiss normal coronary arteries: Consider microvascular angina in patients with typical symptoms but normal coronary arteries on angiography 1, 5
• Do not perform provocative testing without appropriate monitoring: These tests require ability to immediately reverse induced spasm with intracoronary nitroglycerin 3
• Do not rely solely on exercise ECG in patients with baseline ECG abnormalities: Use stress imaging instead 3
• Do not overlook variant angina: Document ST-segment elevation during pain episodes, as this diagnosis requires specific treatment with calcium channel blockers rather than beta-blockers 3