Management of Coronary Lesions Detected on CT Coronary Angiography
Need for Additional Imaging After CTA
Coronary lesions detected on CT coronary angiography (CTCA) require additional imaging based on the CAD-RADS classification, stenosis severity, and clinical presentation. The management approach should follow a systematic algorithm based on the CAD-RADS 2.0 guidelines 1.
Decision Algorithm Based on CAD-RADS Classification:
CAD-RADS 0-2 (0-49% stenosis): No additional imaging is typically required; consider preventive therapy and risk factor modification 1
CAD-RADS 3 (50-69% stenosis): Consider functional assessment with CT-FFR, CTP, or stress testing (ETT, stress echocardiogram, SPECT, PET, or cardiac MRI) to document or exclude ischemia, especially if the patient has persistent symptoms despite medical therapy 1
CAD-RADS 4A (70-99% stenosis in 1-2 vessels): Further evaluation with invasive coronary angiography (ICA) or functional imaging is usually recommended depending on lesion location, extent, severity, and clinical characteristics 1
CAD-RADS 4B (Left main stenosis ≥50% or 3-vessel disease >70%): Further evaluation with ICA and possible revascularization is usually recommended, particularly for patients with frequent symptoms despite optimal medical therapy 1, 2
CAD-RADS 5 (Total occlusion): Consider ICA for definitive evaluation and potential intervention 1
Factors Influencing Need for Additional Imaging
The decision for additional imaging should consider:
Stenosis severity: Very high-grade stenosis (>90%) typically warrants ICA 1, 2
Plaque characteristics: High-risk plaque features (positive remodeling, low attenuation, spotty calcifications) are associated with increased risk of acute coronary syndrome and may favor ICA 3, 4, 5
Clinical presentation: Persistent anginal symptoms despite medical therapy should favor ICA 1, 2
Evidence of ischemia: Presence of lesion-specific ischemia on CT-FFR or perfusion defects by myocardial CTP may favor ICA 1
Special Considerations
Non-coronary cardiac surgery planning: CTCA can effectively rule out significant CAD, with only about 17% of patients requiring additional CAG after initial CTCA 6
Suspected spontaneous coronary artery dissection (SCAD): If SCAD is suspected on CTCA, additional imaging with ICA and possibly OCT/IVUS may be needed for definitive diagnosis 1
Vulnerable plaque assessment: While CTCA can identify some high-risk plaque features, it cannot reliably distinguish all vulnerable plaques that may lead to acute coronary events 7, 4
Imaging Modality Selection
CT-derived FFR (CT-FFR): Non-invasive assessment of lesion-specific ischemia without additional testing 1, 2
Stress testing options: Exercise ECG, stress echocardiogram, SPECT, PET, or cardiac MRI can provide functional assessment of stenosis significance 1
Invasive coronary angiography: Provides definitive assessment of coronary anatomy and allows for intervention; particularly valuable for high-grade stenosis or when revascularization is being considered 1
Pitfalls to Avoid
Overreliance on stenosis severity alone: Functional significance of stenosis does not always correlate with anatomic severity 1, 2
Ignoring plaque characteristics: Plaque composition and morphology provide important prognostic information beyond stenosis severity 3, 4, 5
Inadequate image quality: Non-diagnostic studies (CAD-RADS N) require additional or alternative evaluation 1
Missing non-atherosclerotic causes: Consider conditions like spontaneous coronary artery dissection that may require specific management approaches 1