Background: The role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (Delta FFRCT) in guiding downstream testing in patients with stable coronary artery... Show moreBackground: The role of change in fractional flow reserve derived from CT (FFRCT) across coronary stenoses (Delta FFRCT) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown. Objectives: To investigate the incremental value of Delta FFRCT in predicting early revascularization and improving efficiency of catheter laboratory utilization. Materials: Patients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFRCT was measured 2 cm distal to stenosis. Delta FFRCT was manually measured as the difference of FFRCT across visible stenosis. Results: Of 4730 patients (66 +/- 10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. AFFRCT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26-1.35]; p < 0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFRCT. Among the 3 models (model 1: risk factors + stenosis type and location + CAD-RADS; model 2: model 1 + FFRCT; model 3: model 2 + AFFRCT), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86-0.88] vs 0.85 [0.84-0.86]; p < 0.001), with the greatest incremental value for FFRCT 0.71-0.80. AFFRCT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS >3 and lesion-specific FFRCT <0.8, a diagnostic strategy incorporating AFFRCT >0.13, would potentially reduce ICA by 32.2% (1638-1110, p < 0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%. Conclusions: AFFRCT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFRCT, particularly for those with FFRCT 0.71-0.80. AFFRCT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization. Show less
