What is the management plan for a patient with severe coronary artery stenosis diagnosed via CT (Computed Tomography) angiography of the heart?

Management of Severe Coronary Artery Stenosis Detected on CT Angiography

For patients with severe coronary artery stenosis (70-99%) detected on CT angiography, invasive coronary angiography (ICA) with consideration for revascularization is recommended, particularly if the patient has symptoms despite optimal medical therapy. 1

Initial Assessment and Risk Stratification

• Severe coronary stenosis (70-99%) on CT angiography is classified as CAD-RADS 4, which requires further evaluation and management 1
• CAD-RADS 4 is further subdivided into:
  • CAD-RADS 4A: Severe stenosis (70-99%) in one or two vessels 1
  • CAD-RADS 4B: Left main stenosis ≥50% or three-vessel obstructive disease (>70%) 1

Management Algorithm Based on CAD-RADS Classification

For CAD-RADS 4A (Severe stenosis in one or two vessels):

1. Medical Therapy:

   • Initiate aggressive risk factor modification and preventive pharmacotherapy 1
   • Implement anti-anginal therapy per guideline-directed care 1

2. Further Evaluation:

   • Consider invasive coronary angiography (ICA) or functional assessment 1
   • Functional assessment options include:
     • CT-derived fractional flow reserve (CT-FFR) 1
     • CT myocardial perfusion imaging (CTP) 1
     • Other stress testing (exercise ECG, stress echocardiogram, SPECT, PET, or cardiac MRI) 1

3. Decision for ICA:

   • ICA is particularly favored if any of the following are present:
     • Very high-grade stenosis (>90%) 1
     • High-risk plaque features 1
     • Evidence of lesion-specific ischemia (positive CT-FFR or perfusion defects) 1
     • Persistent symptoms despite optimal medical therapy 1

For CAD-RADS 4B (Left main stenosis ≥50% or three-vessel disease):

1. Immediate Action:
   • Further evaluation with ICA and consideration for revascularization is strongly recommended 1
   • This is particularly important for patients with frequent symptoms despite optimal medical therapy 1

Revascularization Considerations

• The decision between percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) should be based on: 1

  • Coronary anatomy complexity
  • Left ventricular function
  • Presence of comorbidities
  • Patient preference

• For single-vessel disease, PCI with stenting of the culprit lesion is typically the first choice 1

• For multivessel disease, CABG may offer survival benefit, especially with left ventricular dysfunction 1

Functional Assessment During ICA

• When ICA is performed, selective assessment of functional severity of intermediate stenoses is recommended using: 1
  • Fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) (significant if ≤0.8 or ≤0.89, respectively) 1
  • Quantitative flow ratio (QFR) (significant if ≤0.8) 1

Special Considerations

• For patients with severe stenosis and acute chest pain, an immediate invasive strategy (<2 hours) may be warranted if there is hemodynamic instability, refractory angina, or other high-risk features 1
• For stable patients with severe stenosis, a deferred approach (12-48 hours) while optimizing medical therapy may be reasonable 1

Common Pitfalls to Avoid

• Relying solely on anatomical assessment without functional evaluation may lead to unnecessary interventions 2
• Underestimating the significance of severe stenosis in asymptomatic patients 1
• Failing to consider that long narrowings decrease coronary blood flow more than short narrowings of the same severity 2
• Not recognizing that sequential narrowings have a greater hemodynamic impact than a single narrowing of the same total length 2

Follow-up After Management

• After revascularization, patients require:
  • Dual antiplatelet therapy (duration based on intervention type) 1
  • Continued risk factor modification 1
  • Regular clinical follow-up to assess for recurrent symptoms 1