Clinical Management and Outcomes Based on Functional CAD-RADS Compared to Anatomical CAD-RADS in Patients with Stable Coronary Artery Disease.
PURPOSE While anatomical Coronary Artery Disease Reporting and Data System (CAD-RADS) is widely used for coronary CT angiography (CCTA) reporting, it has limited specificity for predicting lesion-specific ischemia. This study evaluates whether the novel functional CAD-RADS, integrating CT-derived fractional flow reserve (CT-FFR), provides superior 5-year prognostic value in patients with stable coronary artery disease (CAD). METHODS A single-center prospective cohort study enrolled 1096 participants aged ≥18 years with CAD referred for CCTA with stenosis degrees of 25%-80%. Primary endpoints were major adverse cardiac events (MACE). The appropriateness of management decisions relative to anatomical or functional CAD-RADS recommendations was explored. Statistical analyses included Kaplan-Meier estimates, Cox proportional hazards models, measures of integrated discrimination improvement (IDI) and net reclassification improvement (NRI). RESULTS After a median follow-up of 64 months, 158 MACEs occurred. Both functional and anatomical CAD-RADS categories predicted MACE (p < 0.001). Functional CAD-RADS showed a higher C-index (0.780; 95% confidence interval [CI]: 0.764, 0.796) compared to anatomical CAD-RADS (0.723; 95% CI: 0.703, 0.743) for predicting MACE (p=0.035), with improved discrimination (IDI: 0.053 [95% CI: 0.016, 0.110]; p=0.008). The proportion of inappropriate management decisions was lower for functional CAD-RADS (9.9%) than for anatomical CAD-RADS (11.0%, p<0.001). The hazard ratios for MACE when comparing dichotomous appropriate and inappropriate management decisions relative to functional CAD-RADS were 9.544 (95% CI: 5.794, 15.720; p<0.001), and 2.475 (95% CI: 1.369, 4.474); p<0.001) for anatomical CAD-RADS recommendations, corresponding to the number needed to treat of 1.912 (95% CI: 1.605, 2.364), and 5.076 (95% CI: 3.546, 10.204), respectively. CONCLUSION Functional CAD-RADS may offer improved predictive power for moderate-term outcomes compared to anatomical CAD-RADS, suggesting potential clinical utility in guiding patient management and informing treatment algorithms for CAD, particularly in patients with intermediate stenosis.