P6170Incremental value of on-site computed tomography-derived fractional flow reserve for the diagnosis and management strategy of obstructive coronary artery disease in the randomized CRESCENT trials

Abstract Background Coronary computed tomography angiography (CCTA) accurately rules out coronary artery disease (CAD), but has a limited ability to predict hemodynamically significant CAD. Implementing on-site computed tomography-derived fractional flow reserve (CT-FFR) could improve the clinical value and efficiency of cardiac CT in the diagnostic work-up of patients with stable angina. Purpose To determine the impact of on-site CT-FFR on diagnostic effectiveness, management strategy and downstream invasive coronary angiography (ICA) in patients with suspected CAD. Methods 196 patients (59.1±9.6 years, 47% women) with suspected CAD underwent a CCTA in the CRESCENT I and II trials. On-site CT-FFR analysis was performed in all patients with at least one ≥50% stenosis on CCTA (N=53). We assessed the effect of adding CT-FFR analysis to CCTA in terms of 1) diagnostic effectiveness, i.e. the number of additional tests required to determine the final diagnosis; 2) reclassification of the initial management strategy; 3) ICA efficiency, i.e. ICA rate without ≥50% CAD. Results CT-FFR was calculated in 42/53 (79%) of the eligible patients as it could not be calculated in patients with suspected coronary total occlusion (N=7), severe coronary calcification (N=2), severe CT artefacts (N=1) or missing CT images (N=1). CT-FFR ≤0.80 was present in 27/196 (14%) patients, including 8/196 (4%) patients with high-risk ischemia (CT-FFR ≤0.80 in all three vessels, left main or proximal left anterior descending coronary artery). The final diagnosis was achieved with CT-FFR in an additional 30/196 (15%) patients compared to CT alone (p<0.0001), and rendered 42/56 (75%) of additional tests unnecessary (p<0.0001). The initial management strategy was reclassified in 30/196 patients (15%, p<0.0001); 24/196 (12%) patients were reclassified to optimal medical therapy and 6/196 (3%) patients were reclassified directly to ICA including 4/8 (50%) patients with high-risk CAD on ICA. CT-FFR would result in 6/32 (19%, p=0.012) ICA cancellations in which none of the patients had high-risk CAD. The rate of ICA without ≥50% stenosis would decrease from 22% (7/32) to 11% (3/27) (p=0.012). Conclusion Implementation of CT-FFR has the potential for improved diagnostic effectiveness. Functional reclassification of CAD provides more efficient ICA referral in patients with suspected CAD compared to CTA alone. Acknowledgement/Funding Dutch Heart Foundation [NHS 2014T061 and NHS 2013T071]