Coronary Artery Disease - Reporting and Data System

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The Coronary Artery Disease - Reporting and Data System (CAD-RADS) is a standardized findings communication method and clinical decision aid relevant to coronary CT angiography. The system was created by a collaboration of the Society for Cardiovascular Computed Tomography (SCCT), American College of Radiology (ACR), and North American Society for Cardiovascular Imaging (NASCI) and was also endorsed by the American College of Cardiology (ACC). The system was published in 2016 .

A CAD-RADS classification is applied per patient, representing the most severely obstructive coronary artery lesion identified. Each category describes an imaging interpretation as well as further management recommendations. This system is intended for patients with two different clinical presentations:

  • patients presenting with stable chest pain
  • patients presenting with acute chest pain, negative first troponin, negative or nondiagnostic electrocardiogram, and low to intermediate risk (Thrombolysis In Myocardial Infarction (TIMI) risk score <4) (emergency department or hospital setting)

Interpretation categories

Stable chest pain
  • CAD-RADS 0: documented absence of coronary artery disease
    • 0% maximal coronary stenosis and no plaque
  • CAD-RADS 1: minimal nonobstructive coronary artery disease
    • 1-24% maximal coronary stenosis = minimal stenosis, or
    • plaque with no stenosis (positive remodeling)
  • CAD-RADS 2: mild nonobstructive coronary artery disease
    • 25-49% maximal coronary stenosis = mild stenosis
  • CAD-RADS 3: moderate stenosis
    • 50-69% maximal coronary stenosis
  • CAD-RADS 4: severe stenosis
    • CAD-RADS 4A: 70-99% maximal coronary stenosis
    • CAD-RADS 4B: left main >50% stenosis or three-vessel obstructive (≥70% stenosis) disease
  • CAD-RADS 5: total coronary occlusion
    • 100% maximal coronary stenosis = total occlusion
  • CAD-RADS N: obstructive coronary artery disease cannot be excluded
    • nondiagnostic study
Acute chest pain, negative first troponin, negative or non-diagnostic electrocardiogram, and low to intermediate risk
  • CAD-RADS 0: acute coronary syndrome highly unlikely
    • 0% maximal coronary stenosis
  • CAD-RADS 1: acute coronary syndrome highly unlikely
    • 1-24% maximal coronary stenosis, or
    • plaque with no stenosis (positive remodeling)
  • CAD-RADS 2: acute coronary syndrome unlikely
    • 25-49% maximal coronary stenosis
  • CAD-RADS 3: acute coronary syndrome possible
    • 50-69% maximal coronary stenosis
  • CAD-RADS 4: acute coronary syndrome likely
    • CAD-RADS 4A: 70-99% maximal coronary stenosis
    • CAD-RADS 4B: left main >50% stenosis or three-vessel obstructive (≥70% stenosis) disease
  • CAD-RADS 5: acute coronary syndrome very likely
    • 100% maximal coronary stenosis = total occlusion
  • CAD-RADS N: acute coronary syndrome cannot be excluded
    • nondiagnostic study

Management recommendations

Recommendations for further cardiac investigation and therapeutic approach accompanies each CAD-RADS category and is different for these two groups of patients.

Stable chest pain
  • CAD-RADS 0
    • no further cardiac investigation
    • reassurance; consider nonatherosclerotic causes of chest pain 
  • CAD-RADS 1
    • no further cardiac investigation
    • consider nonatherosclerotic causes of chest pain; consider preventive therapy and risk factor modification 
  • CAD-RADS 2
    • no further cardiac investigation
    • consider non-atherosclerotic causes of chest pain; consider preventive therapy and risk factor modification, particularly for patients with nonobstructive plaque in multiple segments
  • CAD-RADS 3
    • consider functional assessment
    • consider symptom-guided anti-ischemic and preventive pharmacotherapy as well as risk factor modification per guideline-directed care; other treatments should be considered per guideline-directed care 
  • CAD-RADS 4
    • CAD-RADS 4A: consider invasive coronary angiography or functional assessment
    • CAD-RADS 4B: invasive coronary angiography is recommended
    • consider symptom-guided anti-ischemic and preventive pharmacotherapy as well as risk factor modification per guideline-directed care; other treatments (including options of revascularization) should be considered per guideline-directed care 
  • CAD-RADS 5 
    • consider invasive coronary angiography and/or viability assessment
    • consider symptom-guided anti-ischemic and preventive pharmacotherapy as well as risk factors modification per guideline-directed care; other treatments (including options of revascularization) should be considered per guideline-directed care.
  • CAD-RADS N
    • ​additional or alternative evaluation may be needed
Acute chest pain, negative first troponin, negative or non-diagnostic electrocardiogram, and low to intermediate risk
  • CAD-RADS 0
    • no further evaluation of acute coronary syndrome is required; consider other etiologies
  • CAD-RADS 1
    • consider evaluation of non-acute coronary syndrome etiology, if normal troponin and no ECG changes
    • consider referral for outpatient follow-up for preventive therapy and risk factor modification
  • CAD-RADS 2
    • consider evaluation of non-acute coronary syndrome etiology, if normal troponin and no ECG changes
    • consider referral for outpatient follow-up for preventive therapy and risk factor modification
    • if clinical suspicion of acute coronary syndrome is high or if high-risk plaque features are noted, consider hospital admission with cardiology consultation
  • CAD-RADS 3  
    • consider hospital admission with cardiology consultation, functional testing, and/or invasive coronary angiography for evaluation and management.
    • recommendation for anti-ischemic and preventive management should be considered as well as risk factor modification; other treatments should be considered if presence of hemodynamically significant lesion.
  • CAD-RADS 4
    • consider hospital admission with cardiology consultation; further evaluation with invasive coronary angiography and revascularization as appropriate
    • recommendation for anti-ischemic and preventive management should be considered as well as risk factor modification
  • CAD-RADS 5 
    • consider expedited invasive coronary angiography on a timely basis and revascularization if appropriate if acute occlusion
    • recommendation for anti-ischemic and preventive management should be considered as well as risk factor modifications. 
  • CAD-RADS N
    • additional or alternative evaluation for acute coronary syndrome is needed 

Modifiers

If more than one modifier is present, the symbol “/” (slash) should follow each modifier in the following order:

  • modifier N: nondiagnostic
  • modifier S: stent
  • modifier G: graft
  • modifier V: vulnerability​

For example:

  • mild stenosis due to plaque with high-risk features: CAD-RADS 2/V
  • non-interpretable coronary stent without evidence of other obstructive coronary disease: modifier S = CAD-RADS N/S
  • presence of stent and a new moderate stenosis showing a plaque with high-risk features: modifiers S and V=CAD-RADS 3/S/V
  • presence of stent, grafts and non-evaluable segments due to metal artifacts: modifiers S and G=CAD-RADS N/S/G
  • presence of patent left internal mammary artery (LIMA) to the left anterior descending artery (LAD) and expected occluded proximal LAD. Mild non-obstructive stenosis in the right coronary artery (RCA) and left circumflex artery (LCx. modifier G = CAD-RADS 2/G
  • for a patient with severe stenosis (70-99%) in one segment and a non-diagnostic area in another segment, the study should be graded as CAD-RADS 4/N

See also