What tests are recommended before undergoing a coronary angiogram?

Pre-Coronary Angiography Testing

Before proceeding to coronary angiography, patients should undergo clinical risk assessment, ECG, basic laboratory testing including troponins and renal function, and—in most cases—non-invasive testing (CCTA for low-moderate risk, functional imaging for moderate-high risk) unless they present with severe refractory symptoms, very high clinical likelihood of disease, or hemodynamic instability. 1

Initial Clinical Assessment and Basic Testing

Mandatory Baseline Evaluation

• Clinical risk stratification using age, ECG findings, anginal threshold, presence of diabetes, chronic kidney disease (CKD), and left ventricular ejection fraction (LVEF) is required before any invasive procedure 1
• 12-lead ECG must be obtained to assess for ST-segment changes, prior infarction, conduction abnormalities, and left ventricular hypertrophy 1
• Laboratory testing should include:
  • Troponin T or I (Class I recommendation) 1
  • CK-MB 1
  • Renal function (creatinine/eGFR) to assess contrast nephropathy risk 1
  • High-sensitivity C-reactive protein and/or fibrinogen should be considered (Class IIa) 1

Pre-Test Probability Assessment

• Estimate pre-test likelihood of obstructive coronary artery disease (CAD) using the Risk Factor-weighted Clinical Likelihood model 1
• Adjust this estimate using peripheral artery examination findings, resting ECG abnormalities, resting echocardiography results, and presence of vascular calcifications on prior imaging 1

Non-Invasive Testing Strategy (Risk-Stratified Approach)

Very Low Risk (≤5% Pre-Test Probability)

• Defer further diagnostic testing (Class IIa recommendation) 1
• Coronary angiography is not recommended in asymptomatic patients with no evidence of ischemia 1

Low to Moderate Risk (>5%–50% Pre-Test Probability)

• Coronary CT angiography (CCTA) is the preferred initial test (Class I recommendation) 1
• CCTA excels at ruling out obstructive disease with high negative predictive value (99.6% in vessel-based analysis) 2
• Coronary artery calcium scoring (CACS) should be considered in the low range (>5%–15%) to reclassify patients and identify those with very low likelihood 1
• If CCTA is non-diagnostic or shows CAD of uncertain functional significance, proceed to functional imaging 1

Moderate to High Risk (>15%–85% Pre-Test Probability)

Functional imaging is recommended as the initial test (Class I) 1:

• Stress echocardiography with assessment of wall motion abnormalities (≥3 of 16 segments with stress-induced hypokinesia/akinesia indicates high risk) 1
• SPECT or preferably PET myocardial perfusion imaging to diagnose and quantify ischemia (≥10% of LV myocardium indicates high risk) 1
• Stress CMR perfusion imaging to diagnose ischemia and scar (≥2 of 16 segments with perfusion defects indicates high risk) 1

Very High Risk (>85% Pre-Test Probability)

• Proceed directly to invasive coronary angiography without non-invasive testing if severe symptoms are refractory to medical therapy, angina occurs at low exercise levels, or there is hemodynamic instability (Class I) 1

Specific Clinical Scenarios Requiring Direct Angiography

Bypass Non-Invasive Testing Entirely (Class I Indications)

• Survived sudden cardiac death or life-threatening ventricular arrhythmia 1
• Symptoms and signs of heart failure requiring risk assessment 1
• Unstable angina, particularly when intermediate or high-risk noncardiac surgery is scheduled 1
• De novo symptoms highly suggestive of obstructive CAD occurring at low exercise levels after cardiologist assessment 1
• Hemodynamic instability or recurrent life-threatening arrhythmias 1

Reasonable to Proceed to Angiography (Class IIa)

• Depressed LV function (EF <50%) with moderate-risk criteria on non-invasive testing showing demonstrable ischemia 1
• Inconclusive or inadequate non-invasive testing results 1
• High-risk features on non-invasive testing despite preserved LV function 1
• Evidence of high risk for adverse outcomes based on non-invasive test results 1

Pre-Procedural Preparation When Angiography Is Indicated

Access Site Planning

• Radial artery access is the preferred access site (Class I recommendation) when invasive coronary angiography (ICA) is indicated 1

Functional Assessment Availability

• Coronary pressure assessment must be available during ICA to evaluate functional severity of intermediate non-left main stenoses prior to revascularization (Class I) 1
• FFR/iFR (significant ≤0.8 or ≤0.89 respectively) or QFR (significant ≤0.8) should be ready for selective use 1

Baseline Medical Therapy

High-risk patients should receive baseline treatment including:

• Aspirin 1
• Low-molecular-weight heparin 1
• Clopidogrel (may need to be held 5 days before CABG if identified) 1
• Beta-blockers if not contraindicated 1
• Nitrates 1

Common Pitfalls to Avoid

• Do not perform angiography in patients who elect not to undergo revascularization or are not candidates due to comorbidities (Class III) 1
• Do not skip non-invasive testing in stable patients with intermediate risk—this leads to unnecessary invasive procedures 3, 2
• Do not rely solely on anatomic stenosis severity—functional assessment with FFR/iFR is essential for intermediate lesions 1
• Avoid routine wire-based pressure assessment of all vessels—use selectively for intermediate stenoses (Class III recommendation against routine use) 1
• Assess renal function before contrast exposure—particularly critical in elderly, diabetic, and CKD patients 1

Quality Considerations

The 2012 ACC/AHA guidelines note that 4% of coronary angiograms were of unacceptable quality and 48% had technical deficiencies in a New York State sample, with only 70% interobserver agreement 1. This underscores the importance of ensuring adequate non-invasive testing is performed first when clinically appropriate, as angiography has inherent limitations despite being the gold standard 1, 4.