P6174On-site CT-derived FFR predicts the need for revascularization

Abstract

Abstract Background and purpose Coronary computed tomography angiography (CTA) in combination with CT-derived fractional flow reserve (CT-FFR) is a solid tool for assessing both the anatomical and functional impact of coronary atherosclerotic disease (CAD) in a single study. The development of new software for on-site CT-FFR quantification may reduce costs and increase availability. The aim of this study was to analyze the incremental value of CT-FFR over CTA alone and its ability to predict the need for revascularization. Methods Patients referred for invasive coronary angiography (ICA) who accepted to undergo a CTA/CT-FFR study were prospectively included. Patients with any contraindication for CT, atrial fibrillation, chronic total occlusions, severe ventricular hypertrophy or previous coronary revascularization were excluded. On-site CT-FFR was calculated for each coronary vessel. Invasive FFR was quantified during ICA, considering ≤0.8 as a surrogate for the need for revascularization. Results 33 patients (90 vessels) were included. Mean age was 65±10 years, 88% were males, 60% had hypertension, 77% dyslipidaemia and 40% diabetes. The average analysis time of CT-FFR was 16±4 minutes. There was a good correlation between CT-FFR and FFR in all three main epicardial vessels as well as in proximal segments or in moderate to severe stenosis (see Table). 83% of vessels with FFR≤0.8 were predicted by CT-FFR study (89% of LAD lesions, 86% of LCX and 66% of RCA). CT-FFR added incremental diagnostic value over CTA alone to predict FFR≤0.8 (ΔAUC 0.0336 with a net reclassification index 1.4±0.23; p<0.001) (see Image). n Mean difference from Bland-Altman Pearson's r coefficient p value All-vessels 90 0.037±0.1 0.8 <0.001 Lesions in LAD 40 0.005±0.11 0.81 <0.001 Lesions in LCX 32 0.061±0.094 0.85 <0.001 Lesions in RCA 18 0.06±0.11 0.83 <0.001 Moderate lesions (50–69% QCA stenosis) 24 0.02±0.06 0.88 <0.001 Severe lesions (70–99% QCA stenosis) 25 0.034±0.18 0.4 <0.001 Proximal lesions 42 0.012±0.11 0.84 <0.001 Non-proximal lesions 48 0.061±0.1 0.78 <0.001 Conclusions On-site CT-FFR is a good predictor of the need for revascularization in all three main coronary vessels and adds incremental diagnostic value over CTA alone. There is higher dispersion of the values in severe stenosis, lesions in LCX or RCA although this do not result in misclassification.