Derivation and validation of a novel functional FFR _CT 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 (FFR CT) may be a better predictor of clinical events than either parameter alone. Methods: The Functional FFR CT Score (FFS) combines CCTA and FFR CT 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 FFR CT 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 intra-operator and inter-operator agreement (Cohen's Kappa 0.89 (±0.37, p ​&lt; ​0.001) and 0.83 (±0.04, p ​&lt; ​0.001, respectively). The FFS correlated strongly with both the CT-SYNTAX and the Functional CT-SYNTAX scores (rS ​= ​0.808 for both, p ​&lt; ​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 ​&lt; ​0.001. Patients in the highest FFS tertile had significantly higher rates of revascularization (61 ​% vs 5 ​%, p ​&lt; ​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 ​&lt; ​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.</p

Randomized comparison of chest pain evaluation with FFRCT or standard care: Factors determining US costs

Background: FFR CT assesses the functional significance of lesions seen on CTCA, and may be a more efficient approach to chest pain evaluation. The FORECAST randomized trial found no significant difference in costs within the UK National Health Service, but implications for US costs are unknown. The purpose of this study was to compare costs in the FORECAST trial based on US healthcare cost weights, and to evaluate factors affecting costs. Methods: patients with stable chest pain were randomized either to the experimental strategy (CTCA with selective FFR CT), or to standard clinical pathways. Pre-randomization, the treating clinician declared the planned initial test. The primary outcome was nine-month cardiovascular care costs. Results: planned initial tests were CTCA in 912 patients (65%), stress testing in 393 (28%), and invasive angiography in 94 (7%). Mean US costs did not differ overall between the experimental strategy and standard care (cost difference +7% (+$324), CI −12% to +26%, p ​= ​0.49). Costs were 4% lower with the experimental strategy in the planned invasive angiography stratum (p for interaction ​= ​0.66). Baseline factors independently associated with costs were older age (+43%), male sex (+55%), diabetes (+37%), hypertension (+61%), hyperlipidemia (+94%), prior angina (+24%), and planned invasive angiography (+160%). Post-randomization cost drivers were coronary revascularization (+348%), invasive angiography (267%), and number of tests (+35%). Conclusions: initial evaluation of chest pain using CTCA with FFR CT had similar US costs as standard care pathways. Costs were increased by baseline coronary risk factors and planned invasive angiography, and post-randomization invasive procedures and the number of tests. Registration at ClinicalTrials.gov (NCT03187639). </p

Randomized comparison of chest pain evaluation with FFRCT or standard care: factors determining US costs

Background: FFRCT assesses the functional significance of lesions seen on CTCA, and may be a more efficient approach to chest pain evaluation. The FORECAST randomized trial found no significant difference in costs within the UK National Health Service, but implications for US costs are unknown. The purpose of this study was to compare costs in the FORECAST trial based on US healthcare cost weights, and to evaluate factors affecting costs. Methods: Patients with stable chest pain were randomized either to the experimental strategy (CTCA with selective FFRCT), or to standard clinical pathways. Pre-randomization, the treating clinician declared the planned initial test. The primary outcome was nine-month cardiovascular care costs. Results: Planned initial tests were CTCA in 912 patients (65%), stress testing in 393 (28%), and invasive angiography in 94 (7%). Mean US costs did not differ overall between the experimental strategy and standard care (cost difference +7% (+$324), CI −12% to +26%, p ​= ​0.49). Costs were 4% lower with the experimental strategy in the planned invasive angiography stratum (p for interaction ​= ​0.66). Baseline factors independently associated with costs were older age (+43%), male sex (+55%), diabetes (+37%), hypertension (+61%), hyperlipidemia (+94%), prior angina (+24%), and planned invasive angiography (+160%). Post-randomization cost drivers were coronary revascularization (+348%), invasive angiography (267%), and number of tests (+35%). Conclusions: Initial evaluation of chest pain using CTCA with FFRCT had similar US costs as standard care pathways. Costs were increased by baseline coronary risk factors and planned invasive angiography, and post-randomization invasive procedures and the number of tests. Registration at ClinicalTrials.gov (NCT03187639)