Impact of coronary CT image quality on the accuracy of the FFRCT Planner

Objective To assess the accuracy of a virtual stenting tool based on coronary CT angiography (CCTA) and fractional flow reserve (FFR) derived from CCTA (FFRCT Planner) across different levels of image quality. Materials and methods Prospective, multicenter, single-arm study of patients with chronic coronary syndromes and lesions with FFR <= 0.80. All patients underwent CCTA performed with recent-generation scanners. CCTA image quality was adjudicated using the four-point Likert scale at a per-vessel level by an independent committee blinded to the FFRCT Planner. Patient- and technical-related factors that could affect the FFRCT Planner accuracy were evaluated. The FFRCT Planner was applied mirroring percutaneous coronary intervention (PCI) to determine the agreement with invasively measured post-PCI FFR. Results Overall, 120 patients (123 vessels) were included. Invasive post-PCI FFR was 0.880.06 and Planner FFRCT was 0.860.06 (mean difference 0.02 FFR units, the lower limit of agreement (LLA)-0.12, upper limit of agreement (ULA) 0.15). CCTA image quality was assessed as excellent (Likert score 4) in 48.3%, good (Likert score 3) in 45%, and sufficient (Likert score 2) in 6.7% of patients. The FFRCT Planner was accurate across different levels of image quality with a mean difference between FFRCT Planner and invasive post-PCI FFR of 0.020.07 in Likert score 4, 0.020.07 in Likert score 3 and 0.030.08 in Likert score 2, p=0.695. Nitrate dose >= 0.8mg was the only independent factor associated with the accuracy of the FFRCT Planner (95%CI-0.06 to-0.001, p=0.040). Conclusion The FFRCT Planner was accurate in predicting post-PCI FFR independent of CCTA image quality.