CT-FFR vs a model of combined plaque characteristics for identifying ischemia: Results from CT-FFR CHINA trial

Objectives: To evaluate the diagnostic performance of fractional flow reserve (FFR) derived from coronary computed tomography angiography (CCTA; CT-FFR) and combined plaque characteristics for ischemia in different CCTA stenosis levels. Methods: This clinical trial analyzed 317 patients with 30 %?90 % coronary stenosis in 366 vessels from 5 centers undergoing CCTA and invasive FFR. 366 vessels were assigned into < 50 % (nonobstructive) and > 50 % (obstructive) stenosis groups. Lesion length (LL), plaque burden (PB), diameter stenosis (DS), volume ratio of plaque subcomponents < 30 HU (VR < 30HU), and high-risk features were analyzed. Logistic regression models were used to identify plaque characteristic predictors for lesion-specific ischemia in different stenosis grades. The area under receiver operating characteristics curve (AUC) of integrated plaque characteristics and CT-FFR were calculated and compared. Results: In < 50 % stenosis lesions, PB (OR: 1.296, p = 0.002), LL (OR:1.075, p = 0.020), and DS (OR:1.085, p = 0.031) were independent predictors of ischemia. In > 50 % stenosis lesions, VR < 30HU (OR:1.031, p = 0.005) and DS (OR: 1.020, p = 0.044) were independent predictors for ischemia. AUC of plaque characteristic (VR < 30HU plus DS) for ischemia was 0.67 (95 % CI: 0.61?0.72) in > 50 % stenosis level, which was significantly lower than CT-FFR (AUC=0.90; 95 % CI: 0.86?0.93) (p < 0.001). For lesions causing < 50 % stenosis, AUC of combined plaque model (VR < 30HU plus DS) was 0.88 (95 % CI: 0.80?0.95), equivalent to AUC of CT-FFR (AUC = 0.88; 95 % CI: 0.80?0.96; p = 0.957). Conclusion: CT-FFR is a powerful functional assessment tool for both obstructive and nonobstructive diseases. However, for nonobstructive CAD confirmed by CCTA, a model of a combination of plaque characteristics could be a valuable alternative to CT-FFR.

Automated summary

Plaque characteristics such as plaque burden, lesion length, and diameter stenosis were found to be independent predictors of ischemia in different stenosis levels. The combination model of plaque characteristics showed comparable diagnostic performance to CT-FFR in nonobstructive CAD lesions but was inferior in obstructive lesions. CT-FFR remains a powerful tool for functional assessment in both obstructive and nonobstructive coronary artery disease.