Diagnostic value of comprehensive on-site and off-site coronary CT angiography for identifying hemodynamically obstructive coronary artery disease.

Background: This study aimed to investigate the diagnostic value of comprehensive on-site coronary computed tomography angiography (CCTA) using stenosis and plaque measures and subtended myocardial mass (V) for fractional flow reserve (FFR) defined hemodynamically obstructive coronary artery disease (CAD). Additionally, the incremental diagnostic value of off-site CT-derived FFR (FFR) was assessed.

Methods: Prospectively enrolled patients underwent CCTA followed by invasive FFR interrogation of all major coronary arteries. Vessels with ≥30% stenosis were included for analysis. On-site CCTA assessment included qualitative and quantitative stenosis (visual grading and minimal lumen area, MLA) and plaque measures (characteristics and volumes), and V. Diagnostic value of comprehensive on-site CCTA assessment was tested by comparing area under the curves (AUC). In vessels with available FFR, the incremental value of off-site FFR was tested.

Results: In 236 vessels (132 patients), MLA, positive remodeling, non-calcified plaque volume, and V were independent on-site CCTA predictors for hemodynamically obstructive CAD (p < 0.05 for all). V/MLA outperformed all these on-site CCTA parameters (AUC = 0.85) and V was incremental to all other CCTA predictors (p = 0.02). In subgroup analysis (n = 194 vessels), diagnostic performance of FFR and V/MLA was similar (AUC 0.89 and 0.85 respectively, p = 0.25). Furthermore, diagnostic performance significantly albeit minimally increased when FFR was added to on-site CCTA assessment (ΔAUC = 0.03, p = 0.02).

Conclusions: In comprehensive on-site CCTA assessment, V/MLA2 demonstrated greatest diagnostic value for hemodynamically obstructive CAD and V was incremental to all evaluated CCTA indices. Additionally, adding FFR only minimally increased diagnostic performance, demonstrating that on-site CCTA assessment is a reasonable alternative to FFR.