Coronary Artery Disease - Reporting and Data System

The Coronary Artery Disease - Reporting and Data System (CAD-RADS^TM) classification is proposeda 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), the American College of Radiology (ACR), and the and North American Society for Cardiovascular Imaging (NASCI), last updated and was also endorsed by the American College of Cardiology (ACC). The system was published in 2016¹.

This recommendationA 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 groups of patientsdifferent clinical presentations:

• patients presenting with stable chest pain
• patients presenting with acute chest pain, negative first troponin, negative or non-diagnosticnondiagnostic electrocardiogram, and low to intermediate risk

CAD-RADS for patients presenting with stable chest pain.

• CAD-RADS 0
  • degree of coronary stenosis is 0%
  • documented absence of CAD
  • further cardiac investigation - none
• CAD-RADS 1
  • degree of coronary stenosis is 1%-24% (minimal)
  • minimal non-obstructive CAD 
  • further cardiac investigation - none
• CAD-RADS 2
  • degree of coronary stenosis is 25%-49% (mild)
  • mild non-obstructive CAD 
  • further cardiac investigation - none
• CAD-RADS 3
  • degree of coronary stenosis is 50%-69% (moderate).
  • moderate stenosis 
  • consider functional assessment.
• CAD-RADS 4A
  • degree of coronary stenosis is 70%-99% (severe)
  • severe stenosis 
  • consider angiography or functional assessment
• CAD-RADS 4B
  • left main >50% or three-vessel disease (>70%)
  • severe stenosis 
  • angiography recommended
• CAD-RADS 5
  • coronary stenosis is 100% (total occlusion)
  • total coronary occlusion 
  • angiography recommended
• CAD-RADS N
  • non-diagnostic study
  • obstructive CAD cannot be excluded
  • additional or alternative evaluation may be needed

*CAD - coronary artery disease 

CAD-RADS for patients presenting with acute chest pain, negative first troponin, negative or non-diagnostic 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
  • degree: documented absence of coronary stenosis is artery disease
    • 0%
    • acute maximal coronary syndrome is highly unlikely stenosis and no plaque
  • CAD-RADS 1: minimal nonobstructive coronary artery disease
    • degree of1-24% maximal coronary stenosis is 1%-24% (minimal)= minimal stenosis, or
    • acute coronary syndrome is highly unlikely plaque with no stenosis (positive remodeling)
  • CAD-RADS 2: mild nonobstructive coronary artery disease
    • degree of25-49% maximal coronary stenosis is 25%-49% (mild)= 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 ishighly 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
    • modifier 2/V: vulnerable/high risk plaque
  • CAD-RADS 3
    • degree of coronary stenosis is 50%-69% (moderate)
    • : acute coronary syndrome is possiblepossible
      • 50-69% maximal coronary stenosis
    • CAD-RADS 4A4
      • degree of coronary stenosis is 70%-99% (severe)
      • : acute coronary syndrome is likely
      likely
      • CAD-RADS 4A: 70-99% maximal coronary stenosis
      • CAD-RADS 4B
        • left: left main >50% stenosis or three-vessel diseaseobstructive (>70≥70% stenosis)
        • acute coronary syndrome is likely disease
      • CAD-RADS 5
        • coronary stenosis is 100% (total occlusion)
        • : acute coronary syndrome is very likely
          • 100% maximal coronary stenosis = total occlusion
        • CAD-RADS N
          • non-diagnostic study
          • : acute coronary syndrome cannot be excluded
            • nondiagnostic study

          Management recommendations

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

          Management of patients presenting with stable

          Stable chest pain. 

          • CAD-RADS 0
            • reassuranceno further cardiac investigation
            • reassurance; consider non-atheroscleroticnonatherosclerotic causes of chest pain 
          • CAD-RADS 1
            • no further cardiac investigation
            • consider non-atheroscleroticnonatherosclerotic causes of chest pain
            • consider; 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 non-obstructivenonobstructive plaque in multiple segments
          • CAD-RADS 3
            • consider functional assessment
            • consider symptom-guided anti-ischaemic 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-ischaemic 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-ischaemic and preventive pharmacotherapy as well as risk factors modification per guideline-directed care
            • other; other treatments (including options of revascularization) should be considered per guideline-directed care.
          • CAD-RADS N
            • ​additional or alternative evaluation may be needed

            Management of patients presenting with acute

          Acute chest pain, negative first troponin, negative or non-diagnostic electrocardiogram, and low to intermediate risk(Thrombolysis In Myocardial Infarction (TIMI) risk score <4) (emergency department or hospital setting). 

          • CAD-RADS 0
            • no further evaluation of ACSacute coronary syndrome is required
            • consider; consider other aetiologiesetiologies
          • CAD-RADS 1
            • consider evaluation of non-ACS aetiology-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-ACS aetiology-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 ACSacute 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 ICAinvasive coronary angiography for evaluation and management.
            • recommendation for anti-ischaemic-ischemic and preventive management should be considered as well as risk factor modification
            • other; other treatments should be considered if presence of haemodynamically-significanthemodynamically significant lesion.
          • CAD-RADS 4
            • consider hospital admission with cardiology consultation. Further; further evaluation with ICAinvasive coronary angiography and revascularization as appropriate.
            • recommendation for anti-ischaemic and preventive management should be considered as well as risk factor modification
          • CAD-RADS 5 
            • consider expedited ICAinvasive coronary angiography on a timely basis and revascularization if appropriate if acute occlusion
            • recommendation for anti-ischaemic and preventive management should be considered as well as risk factor modifications. 
          • CAD-RADS N
            • additional or alternative evaluation for ACSacute coronary syndrome is needed 

          * ACS - acute coronary syndrome

          Modifiers

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

          • modifier N (non-diagnostic): nondiagnostic
          • modifier S (stent): stent
          • modifier G (graft): graft
          • modifier V (vulnerability): vulnerability

          For example:

          • 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

          • ACC/AHA classification of coronary lesions