P6176Added value of computed tomography fractional flow reserve (FFRCT) in the diagnosis of coronary artery disease (CAD)

Abstract Purpose Multiple non-invasive tests are performed as part of the standard protocol to diagnose CAD, but all are limited to either anatomical or functional assessments. FFRCT is a new non-invasive test that combines anatomical and functional characteristics based on the principles of invasive FFR. This study aims to evaluate the added value of FFRCT beyond the currently used tests. Methods Patients having the clinical suspicion of angina pectoris between 2010 and 2011 were included in this cross-sectional study. All underwent exercise stress electrocardiography (X-ECG), SPECT, CT coronary angiography (CCTA) and FFRCT as part of the Horoscope study. Invasive coronary angiography (ICA) and FFR were used as reference standard. Missing values were multiple imputed and five combined models mimicking the clinical workflow were fitted. The area under the receiver operating characteristic (AUROC) curve and Akaike Information Criteria (AIC) were used for comparison. Results 89 (44%) of the 202 patients included in the analysis had a FFR of ≤0.80, while positive tests were found for X-ECG, SPECT, CCTA and FFRCT in 41%, 47%, 53% and 50% of the cases. The model including pre-test-likelihood and X-ECG had an AUROC of 0.78 (AIC: 236), which significantly increases to 0.89 by adding SPECT (AIC: 170), to 0.87 by adding CCTA (AIC: 191), to 0.92 when adding FFRCT (AIC: 155) and to 0.94 when adding CCTA and SPECT (AIC: 1 40). ROC-curves for all diagnostic models Model 1 Model 2 Model 3 Model 4 Model 5 Basic model + SPECT + CCTA + CCTA + FFRCT +SPECT + CCTA AIC 236.0 169.8 190.8 154.5 140.1 AUC 0.78 0.89 0.87 0.92 0.94 ROC-curves for all diagnostic models and its AIC and AUC. FFRCT has an improved AUC compared to the basic model and the models including SPECT or CCTA alone, while its AIC is decreased. The model including both SPECT and CCTA has the highest AUC and the lowest AIC and seems therefore the preferable strategy. ROC curve Conclusion This study shows adding FFRCT leads to an increased AUROC and a decreased AIC compared to the basic model. It therefore improves the diagnostic work-up beyond SPECT or CCTA alone in the diagnosis of CAD.