Computed tomography-derived fractional flow reserve (FFRCT) has no additional clinical impact over the anatomical Coronary Artery Disease - Reporting and Data System (CAD-RADS) in real-world elective healthcare of coronary artery disease

Abstract

Aim: To evaluate the impact of computed tomography-derived fractional flow reserve (FFR_CT) compared to the anatomical Coronary Artery Disease - Reporting and Data System (CAD-RADS) in the elective assessment of coronary artery disease in real-world cardiology practise.

Materials and methods: A retrospective review was undertaken of 1,239 coronary CT examinations from August 2018 to December 2019 with a minimum follow-up period of 1 year. Coronary disease was classified according to the CAD-RADS system. A non-occlusive ≥30% maximum diameter stenosis was considered eligible for FFR_CT. Lesion-specific FFR_CT and FFR were considered positive if ≤ 0.80. The patients were followed up using the hospital radiology information system and the electronic patient record. A positive outcome was defined by a subsequent invasive angiogram (ICA) showing disease requiring revascularisation or FFR ≤0.80 or a positive stress test or medical therapy for angina in CAD-RADS 4.

Results: Of the 1,145 analysable studies (mean follow up 618 ± 153 days) the incidence of a positive result was 7% with a 5.4% elective revascularisation rate. Two hundred and forty-five patients (CAD-RADS 2-4) had FFR_CT. FFR_CT reduced the accuracy of the CAD-RADS grade from 91% to 78.4% (p<0.001). In CAD-RADS 2, the accuracy is reduced from 99% to 90.7% (p=0.005), and in CAD-RADS 3 from 93.9% to 67.7% (p<0.001). In CAD-RADS 4, FFR_CT increases accuracy from 69.4% to 75.5% (p=0.025), but 89.8% of FFR_CT are positive and specificity is low (26.7%).

Conclusion: In the present "real-world" practise, FFR_CT does not improve standard radiological assessment of coronary disease graded by the CAD-RADS alone.