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

Lavinia Gabara; Jonathan Hinton; Mohamed Kira; Alec Saunders; James Shambrook; Ausami Abbas; Jonathon A Leipsic; Campbell Rogers; Sarah Mullen; Nicholas Ng; Sam Wilding; Pamela S Douglas; Manesh Patel; Timothy A Fairbairn; Mark A Hlatky; Nick Curzen

doi:10.1016/j.jcct.2023.10.005

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

J Cardiovasc Comput Tomogr. 2024 Jan-Feb;18(1):33-42. doi: 10.1016/j.jcct.2023.10.005. Epub 2023 Oct 21.

Authors

Affiliations

¹ Coronary Research Group, University Hospital Southampton NHS FT, Southampton, UK; Faculty of Medicine, University of Southampton, Southampton, UK.
² Coronary Research Group, University Hospital Southampton NHS FT, Southampton, UK.
³ Department of Cardiothoracic Radiology, Wessex Cardiac Centre, University Hospital Southampton NHS FT, Southampton, UK.
⁴ Department of Radiology and Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.
⁵ HeartFlow Inc., Mountain View, CA, USA.
⁶ Clinical Trials Unit, University of Southampton, UK.
⁷ Division of Cardiology, Department of Medicine, Duke University Medical Centre, Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
⁸ Department of Cardiology, Liverpool Heart and Chest Hospital, Liverpool, UK.
⁹ Division of Cardiovascular Medicine and Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA; Department of Health Policy, Stanford University, Stanford, CA, USA.
¹⁰ Coronary Research Group, University Hospital Southampton NHS FT, Southampton, UK; Faculty of Medicine, University of Southampton, Southampton, UK. Electronic address: nick.curzen@uhs.nhs.uk.

PMID: 37872028
DOI: 10.1016/j.jcct.2023.10.005

Abstract

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 < 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.

Keywords: Coronary artery disease; Coronary computed tomography angiography; Fractional flow reserve derived from computed tomography; Major adverse cardiovascular events; Revascularization; Risk stratification.

MeSH terms

Computed Tomography Angiography / methods
Coronary Angiography / methods
Coronary Artery Disease* / diagnostic imaging
Coronary Artery Disease* / therapy
Coronary Stenosis* / diagnostic imaging
Coronary Stenosis* / therapy
Coronary Vessels / diagnostic imaging
Fractional Flow Reserve, Myocardial*
Humans
Predictive Value of Tests