Cardiac CT — practice case: CCTA in suspected chronic coronary syndrome

Presentation

Practice case (not a real patient). A 59-year-old man in Australia has three months of exertional chest discomfort and is assessed for suspected chronic coronary syndrome. His pre-test likelihood of obstructive CAD by the Risk Factor-weighted Clinical Likelihood model is 22%.^[1] He is in sinus rhythm with a slow and regular heart rate, can follow breath-hold instructions, has an eGFR of 82 mL/min/1.73 m², no contrast allergy, no heart failure and no severe obesity. CCTA is available locally and supported by local expertise.^[1]

Step 1 — Which first test?

Discussion:

• ESC 2024: in symptomatic patients in whom the pre-test likelihood of obstructive CAD by clinical assessment is >5%, CCTA or non-invasive functional imaging for myocardial ischaemia is recommended as the initial diagnostic test (Class I, Level B).^[1]
• At 22% he sits in two ESC 2024 bands for individuals with suspected CCS: CCTA is recommended to diagnose obstructive CAD and estimate the risk of MACE at low or moderate (>5%–50%) pre-test likelihood (Recommendation Table 8, Class I, Level A), and stress echocardiography (to diagnose myocardial ischaemia and estimate the risk of MACE), stress SPECT or, preferably, PET myocardial perfusion imaging (to diagnose and quantify myocardial ischaemia and/or scar, estimate the risk of MACE and, with PET, quantify myocardial blood flow), or stress CMR perfusion imaging (to diagnose and quantify myocardial ischaemia and/or scar and estimate the risk of MACE) are recommended at moderate or high (>15%–85%) pre-test likelihood (Recommendation Tables 9 and 10, Class I, Level B), each if available and supported by local expertise.^[1]
• To rule out obstructive CAD, ESC 2024 recommends CCTA as the preferred diagnostic modality in the >5%–50% band (Class I, Level B), and the choice should rest on pre-test likelihood, patient characteristics that influence test performance, and local expertise and availability (Class I, Level C).^[1]

Step 2 — Is he a good CCTA candidate?

• ESC 2024: a slow and regular heart rate and compliance with breath-holding instructions are generally necessary for good image quality, and kidney function and contrast allergy should be assessed before referral; he meets these.^[1]
• ESC 2024 does not recommend CCTA in patients with severe renal failure (eGFR <30 mL/min/1.73 m²), decompensated heart failure, extensive coronary calcification, fast irregular heart rate, severe obesity, inability to cooperate with breath-hold commands, or any other conditions that can make obtaining good imaging quality unlikely (Class III, Level C); none of the conditions recorded in his presentation applies.^[1]

Step 3 — The CCTA shows non-obstructive plaque

His CCTA shows mild plaque with no stenosis of 50% or more.^[1]

• ESC 2024 says that, besides its strength in ruling out CAD, CCTA offers direct visualization of non-obstructive CAD, which may trigger intensification of preventive measures.^[1]
• ESC 2024 key message: CCTA is preferred to rule out obstructive CAD and detect non-obstructive CAD.^[1]
• AHA/ACC 2021: for patients with known nonobstructive CAD and stable chest pain, it is recommended to optimize preventive therapies (COR 1, LOE C-EO).^[2]

Step 4 — Two years later

His stable exertional symptoms have been managed medically for two years on optimized guideline-directed therapy, with no change in his symptoms or functional capacity. His general practitioner asks whether to repeat the CCTA routinely.^[3]

• He now fits the AHA/ACC 2023 chronic coronary disease population that includes patients with stable angina symptoms (or ischemic equivalents) medically managed with or without positive results of an imaging test.^[3]
• AHA/ACC 2023: in patients with CCD without a change in clinical or functional status on optimized GDMT, routine periodic testing with coronary CTA or stress testing with or without imaging is not recommended to guide therapeutic decision-making (COR 3: No Benefit, LOE B-R).^[3]
• If his symptoms or functional capacity change and the change persists despite GDMT, AHA/ACC 2023 recommends stress PET/SPECT MPI, CMR imaging, or stress echocardiography to detect the presence and extent of myocardial ischemia, estimate risk of MACE, and guide therapeutic decision-making (COR 1, LOE B-NR); this row is marked as modified from the 2021 chest pain guideline.^[3]
• The earlier AHA/ACC 2021 row says that for symptomatic patients with known nonobstructive CAD who have stable chest pain, CCTA is reasonable for determining atherosclerotic plaque burden and progression to obstructive CAD, and guiding therapeutic decision-making (COR 2a, LOE B-NR).^[2]

Examiner criteria

• Pass: places 22% in both ESC 2024 bands and names the CCTA and functional imaging rows with their classes; names CCTA as the ESC 2024 preferred test to rule out obstructive CAD; checks the image-quality prerequisites and the Class III list; recognises that non-obstructive CAD on CCTA may trigger intensification of preventive measures; and declines routine periodic CTA in a patient without a change in clinical or functional status on optimized GDMT, citing the AHA/ACC 2023 row.^[1][3]
• Fail: orders CCTA without checking heart rate, breath-holding and kidney function, or repeats CCTA routinely in a stable patient without a change in clinical or functional status on optimized GDMT.^[1][3]