Derivation and validation of a novel functional FFRCT score incorporating the burden of coronary stenosis severity and flow impairment to predict clinical events

Background: A score combining the burden of stenosis severity on coronary computed tomography angiography (CCTA) and flow impairment by fractional flow reserve derived from computed tomography (FFRCT) may be a better predictor of clinical events than either parameter alone. Methods: The Functional FFRCT Score (FFS) combines CCTA and FFRCT parameters in an allocated point -based system. The feasibility of the FFS was assessed in cohort of 72 stable chest pain patients with matched CCTA and FFRCT datasets. Validation was performed using 2 cohorts: (a) 4468 patients from the ADVANCE Registry to define its association with revascularization and major adverse cardiovascular events (MACE); (b) 212 patients from the FORECAST trial to determine predictors of MACE. Results: The median calculation time for the FFS was 10 (interquartile range 6-17) seconds, with strong intraoperator and inter -operator agreement (Cohen's Kappa 0.89 (+/- 0.37, p < 0.001) and 0.83 (+/- 0.04, p < 0.001, respectively). The FFS correlated strongly with both the CT -SYNTAX and the Functional CT -SYNTAX scores (rS = 0.808 for both, p < 0.001). In the ADVANCE cohort the FFS had good discriminatory abilities for revascularization with an area under the curve of 0.82, 95 % confidence interval (CI) 0.81-0.84, p < 0.001. Patients in the highest FFS tertile had significantly higher rates of revascularization (61 % vs 5 %, p < 0.001) and MACE (1.9 % vs 0.5 %, p = 0.001) compared with the lowest FFS tertile. In the FORECAST cohort the FFS was an independent predictor of MACE at 9 -month follow-up (hazard ratio 1.04, 95 % CI 1.01-1.08, p < 0.01). Conclusion: The FFS is a quick -to -calculate and reproducible score, associated with revascularization and MACE in two distinct populations of stable symptomatic patients.