The role of change in fractional flow reserve derived from CT (FFR _CT ) across coronary stenoses (ΔFFR _CT ) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown.
To investigate the incremental value of ΔFFR _CT in predicting early revascularization and improving efficiency of catheter laboratory utilization.
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 FFR _CT was measured 2 ​cm distal to stenosis. ΔFFR _CT was manually measured as the difference of FFR _CT across visible stenosis.
Of 4730 patients (66 ​± ​10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. ΔFFR _CT 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 FFR _CT . Among the 3 models (model 1: risk factors ​+ ​stenosis type and location ​+ ​CAD-RADS; model 2: model 1 ​+ ​FFR _CT ; model 3: model 2 ​+ ​ΔFFR _CT ), 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 FFR _CT 0.71-0.80. ΔFFR _CT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS ≥3 and lesion-specific FFR _CT ≤0.8, a diagnostic strategy incorporating ΔFFR _CT >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%.
ΔFFR _CT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFR _CT , particularly for those with FFR _CT 0.71-0.80. ΔFFR _CT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization.