Coronary Computed Tomography Angiography (CCTA) is the Primary Test for Detecting Coronary Artery Narrowing
CCTA is recommended as the first-line anatomical imaging test to diagnose obstructive coronary artery disease and detect coronary artery narrowing in patients with suspected chronic coronary syndrome. 1
Primary Diagnostic Test: CCTA
CCTA has the highest diagnostic accuracy among noninvasive tests for detecting significant coronary artery stenosis, with sensitivity of 91-95%, specificity of 83-92%, and area under the curve of 0.91-0.93. 1, 2
CCTA can assess coronary vessels as small as 1.5-2 mm in diameter for atherosclerotic narrowing, including all epicardial vessels (left main, left anterior descending, left circumflex, right coronary artery) and their branches. 1
The 2024 European Society of Cardiology guidelines specifically recommend CCTA (Class I, Level A) for individuals with low or moderate (>5%-50%) pre-test likelihood of obstructive coronary artery disease. 1
Enhanced Functional Assessment: FFR-CT
When CCTA identifies coronary stenosis of intermediate severity (typically 50-70%), FFR-CT should be added to determine hemodynamic significance without additional imaging. 3
FFR-CT dramatically improves diagnostic accuracy over CCTA alone (84% versus 59%) by correctly reclassifying 68% of false-positive CCTA results as true negatives, thereby reducing unnecessary invasive angiography. 1, 3
FFR-CT has sensitivity of 85-93% and specificity of 65-82%, substantially higher than CCTA alone at 32-46% specificity. 1, 3
Important Contraindications to CCTA
CCTA should not be performed in patients with: 1
- Severe renal failure (eGFR <30 mL/min/1.73 m²)
- Decompensated heart failure
- Extensive coronary calcifications
- Fast irregular heart rate
- Severe obesity
- Inability to cooperate with breath-hold commands
Alternative Noninvasive Tests (Secondary Options)
Stress Echocardiography
- Detects myocardial ischemia through regional wall-thickening abnormalities during stress, with diagnostic accuracy similar to other functional imaging modalities. 1
- Advantages include wide availability, low cost, no ionizing radiation, and bedside performance capability. 1
- Major limitation: operator-dependent with compromised image quality in obese patients and those with chronic obstructive pulmonary disease. 1
Coronary MRA
- Limited role with sensitivity of 82-96% and specificity of 68-90% for detecting significant coronary stenosis. 1
- Cannot easily differentiate between calcified and noncalcified plaque, unlike CCTA. 1
- Primarily reserved for when CCTA is contraindicated or non-diagnostic. 1
Myocardial Perfusion Imaging (SPECT/PET)
- Lower diagnostic accuracy than CCTA, with area under the curve of 0.74, sensitivity 74%, and specificity 73%. 2
- High false-positive rate: In patients with hypertrophic cardiomyopathy, 15 of 24 patients (62.5%) had false-positive perfusion abnormalities without actual luminal obstruction on CCTA. 4
Clinical Pitfalls to Avoid
Do not rely solely on coronary calcium scoring: A zero calcium score does not exclude obstructive stenosis in symptomatic patients, as 16% may still have myocardial ischemia on provocative testing. 1
Avoid functional testing as first-line in intermediate-risk patients: CCTA provides superior diagnostic accuracy compared to stress testing and more appropriately triages patients for invasive angiography. 5, 2
FFR-CT is not validated for coronary artery bypass grafts or in-stent assessment and should not be used in these specific situations. 3
Invasive Coronary Angiography
- Reserved for interventional procedures or when noninvasive diagnostic imaging with CT or MRI is inconclusive. 1
- Lacks optimal 3-D information and soft tissue imaging capability compared to CCTA, making it difficult to demonstrate spatial relationships among coronary arteries, myocardium, and great vessels. 1