What testing should be used next after a coronary calcium score indicates mild coronary artery disease?

Next Testing After Coronary Calcium Score Shows Mild Coronary Artery Disease

For patients with mild coronary artery disease detected on coronary calcium scoring, CT-FFR (CT fractional flow reserve), coronary CTP (CT perfusion), or functional stress testing should be considered as the next appropriate testing step, particularly if the patient has symptoms. 1

Understanding CAD-RADS Classification and Next Steps

The 2022 CAD-RADS 2.0 guidelines from the Society of Cardiovascular Computed Tomography provide a structured approach to managing patients based on coronary calcium scores and stenosis severity:

For Mild CAD (CAD-RADS 1 or 2 with mild plaque):

1. If minimal plaque (P1):

   • Consider non-atherosclerotic causes of symptoms
   • No additional cardiac testing typically needed

2. If moderate plaque (P2):

   • Consider non-atherosclerotic causes of symptoms
   • Risk factor modification and preventive pharmacotherapy
   • No additional cardiac testing typically needed

3. If extensive plaque (P3 or P4):

   • Consider non-atherosclerotic causes of symptoms
   • Aggressive risk factor modification and preventive pharmacotherapy
   • Consider additional testing if symptoms persist

For Moderate Stenosis (CAD-RADS 3):

• Consider CT-FFR, CTP, or stress testing
• Aggressive risk factor modification and preventive pharmacotherapy
• Anti-anginal therapy per guideline-directed care

Determining Appropriate Follow-up Testing

The decision for additional testing should be based on:

1. Degree of stenosis:

   • Mild (25-49%) stenosis typically doesn't require immediate functional testing
   • Moderate (50-69%) stenosis warrants consideration of functional assessment

2. Plaque burden:

   • Recent evidence shows that even minimal CAC (scores 1-10) indicates higher non-calcified coronary plaque and total plaque volume than zero CAC, placing these patients at higher CVD risk 2
   • The presence of high-risk plaque features may warrant more aggressive evaluation

3. Symptoms:

   • For symptomatic patients with mild CAD, functional testing helps determine if symptoms are related to coronary disease

Specific Testing Options

1. CT-FFR or CT Perfusion:

   • Non-invasive assessment of functional significance of stenosis
   • Particularly useful for CAD-RADS 3 (moderate stenosis) 1

2. Stress Testing:

   • Exercise ECG
   • Stress echocardiography
   • Nuclear myocardial perfusion imaging
   • Stress cardiac MRI

3. Invasive Coronary Angiography (ICA):

   • Generally reserved for:
     • Severe stenosis (CAD-RADS 4 or 5)
     • Persistent symptoms despite medical therapy
     • High-risk plaque features

Important Considerations and Pitfalls

• Avoid unnecessary testing: For truly mild disease (CAD-RADS 1-2) without symptoms, additional testing may not improve outcomes and could lead to unnecessary procedures

• Don't miss vulnerable plaque: Some patients with only mild stenosis may have vulnerable plaque characteristics that increase risk - consider plaque characterization beyond just calcium score

• Age considerations: Younger patients (<45 years) with any CAC have higher relative risk and may warrant more aggressive evaluation and treatment 1

• Risk factor management is critical: Regardless of testing strategy, aggressive risk factor modification and preventive pharmacotherapy (statins) should be initiated for patients with CAC scores ≥100 or ≥75th percentile for age/sex/race 1

• Beware of radiation exposure: Consider cumulative radiation dose when planning sequential cardiac imaging studies

Algorithm for Next Steps After Calcium Score

1. CAD-RADS 0 (CAC=0):

   • Reassurance
   • Consider non-atherosclerotic causes if symptomatic

2. CAD-RADS 1-2 (Minimal/Mild stenosis) with P1-P2 plaque:

   • Risk factor modification
   • Consider non-atherosclerotic causes if symptomatic
   • No additional cardiac testing typically needed

3. CAD-RADS 1-2 with P3-P4 plaque:

   • Aggressive risk factor modification
   • Preventive pharmacotherapy (statins)
   • Consider functional testing if symptomatic

4. CAD-RADS 3 (Moderate stenosis):

   • CT-FFR, CTP, or stress testing
   • Aggressive risk factor modification and preventive pharmacotherapy
   • Consider ICA if frequent symptoms persist despite medical therapy

5. CAD-RADS 4-5 (Severe stenosis):

   • Consider ICA or functional assessment
   • Aggressive risk factor modification and preventive pharmacotherapy
   • Consider revascularization options

By following this evidence-based approach, clinicians can appropriately risk-stratify patients with mild coronary artery disease detected on calcium scoring and determine the most appropriate next steps for testing and management.