Diagnostic Testing for Coronary Artery Disease

Introduction to Diagnostic Approaches

The European Society of Cardiology recommends coronary CT angiography (CCTA) as the preferred initial test for patients with low to moderate (>5%-50%) pre-test likelihood of obstructive CAD, while functional imaging is recommended for those with moderate to high (>15%-85%) pre-test likelihood 1, 2
The American College of Cardiology suggests that CCTA is the Class I, Level B recommendation as the preferred diagnostic modality for low to moderate risk patients (>5%-50% Pre-test Likelihood) 1, 2
For patients with suspected coronary artery disease, the choice between CCTA and nuclear medicine stress testing depends on the clinical assessment of pre-test likelihood of obstructive CAD, with CCTA preferred for low to moderate risk and functional imaging for moderate to high risk 1, 2

The American College of Cardiology recommends functional imaging (SPECT, PET, stress CMR, or stress echocardiography) as Class I, Level B for moderate to high risk patients (>15%-85% Pre-test Likelihood) 1, 2
Nuclear medicine stress testing (SPECT or preferably PET) is specifically recommended to diagnose and quantify myocardial ischemia and/or scar, and estimate risk of major adverse cardiac events (MACE) 1, 2
Functional testing directly assesses the hemodynamic significance of coronary lesions 5

The American College of Cardiology suggests that younger patients (<65 years) not on optimal preventive therapies may benefit from CCTA 6
Patients where ruling out disease is the primary goal may benefit from CCTA 1, 2
When plaque burden assessment is needed for risk stratification and preventive therapy guidance, CCTA may be preferred 3, 4
After equivocal or non-diagnostic functional testing, CCTA may be considered 1, 5

The European Society of Cardiology states that CCTA should not be used when extensive coronary calcification is present, or in cases of irregular heart rate, atrial fibrillation, significant obesity, or inability to cooperate with breath-hold commands 5, 7, 9
The American College of Cardiology emphasizes that test selection must be based on pre-test likelihood, not simply availability 10, 8

The American College of Cardiology notes that CCTA demonstrates mortality and morbidity benefits through enhanced preventive therapy, with the SCOT-HEART trial showing long-term reduction in death and nonfatal MI with CCTA use 3, 4
Knowledge of plaque presence motivates patients to implement lifestyle changes and seek treatment 3, 4
Nuclear stress testing provides ischemia quantification critical for risk stratification, with area of ischemia ≥10% of LV myocardium on SPECT/PET identifying high-risk patients requiring invasive evaluation 1

The European Society of Cardiology recommends that if CCTA shows CAD of uncertain functional significance, functional imaging should be proceeded with (Class I recommendation) 1, 5
If stress testing is negative but symptoms persist, CCTA may be considered to detect obstructive CAD and atherosclerotic plaque 6
FFR-CT can be added to CCTA for stenoses 40-90% to assess functional significance, avoiding unnecessary invasive procedures 10, 8, 6