The Use of CT Coronary Angiography and CT Fractional Flow Reserve in the Investigation of Patients With Suspected Coronary Artery Disease

Objective To assess the diagnostic performance of CT fractional flow reserve (CT-FFR) and to assess whether its use in addition to CT coronary angiography (CTCA) changed the investigation and management of patients with suspected coronary artery disease (CAD). Method A retrospective case note review was carried out for 200 consecutive patients at Russells Hall Hospital, Dudley, United Kingdom, who had CTCA sent for Heartflow CT-FFR analysis (HeartFlow, Redwood City, CA) between January 2018 and December 2019. Results Patients with CT-FFR > 0.8 were significantly less likely to require further investigation with coronary angiography (p: < 0.00001) than those with CT-FFR < 0.8. The use of CT-FFR significantly reduced need for further functional imaging (6% vs 26%) (p: 0.00012). A total of 15 patients in this study had both a CT-FFR and an invasive FFR measured, with seven (46.66%) of the CT-FFRs correlating with the invasive FFR. Approximately 54% of patients who had a CT-FFR < 0.8 were found to have an invasive FFR of >0.8. Of the 56 patients who underwent coronary angiography, the CT Coronary Artery Disease-Reporting and Data System (CAD-RADS) and angiography CAD-RADS were the same in 66% of the cases with 82% of CT CAD-RADS results being within ±1 of the angiography CAD-RADS. Conclusion The use of CT-FFR alongside CTCA led to a significant reduction in need for coronary angiography and functional testing. Further studies are required to look at the diagnostic accuracy of CT-FFR in direct comparison with invasive FFR.