Calcific versus non-calcific plaque: a CAD-RADS and FFRCT study.

Area of Science:

• Cardiology
• Medical Imaging
• Radiology

Background:

• Coronary Artery Disease-Reporting and Data System (CAD-RADS) standardizes Computed Tomography Coronary Angiography (CTCA) reporting.
• Coronary calcification can potentially overestimate stenosis severity on CTCA.

Purpose of the Study:

• To investigate if CTCA-derived Fractional Flow Reserve (FFRCT) differs between predominantly calcified (Ca+) and non-calcified (Ca-) stenoses within the same CAD-RADS category.
• To assess the impact of calcification on FFRCT values and correlation with Invasive Coronary Angiography (ICA).

Main Methods:

• Retrospective analysis of consecutive patients undergoing routine CTCA with FFRCT correlation (September 2018 to May 2020).
• CTCA lesions were categorized as predominantly calcified (Ca+) or non-calcified (Ca-).
• FFRCT was measured, and potentially flow-limiting lesions were defined as FFRCT ≤ 0.8. Subset underwent ICA.

Main Results:

• No significant difference in FFRCT ≤ 0.8 prevalence between Ca+ and Ca- stenoses across CAD-RADS 2, 3, and 4 categories.
• CAD-RADS 3 Ca+ stenoses showed lower FFRCT compared to Ca- stenoses (maximal stenosis p= .02, end-vessel p= .005).
• No significant differences in FFRCT values or ICA-obstructive disease prevalence between Ca+ and Ca- stenoses in CAD-RADS 2 and 4.

Conclusions:

• Coronary calcification does not consistently lead to an overestimation of functional stenosis severity by FFRCT across all CAD-RADS categories.
• CAD-RADS 3 with calcification may suggest functional underestimation by FFRCT, though not confirmed by ICA.
• FFRCT provides valuable functional information, but the influence of calcification needs consideration, particularly in intermediate CAD-RADS categories.