CCTA and FFR-CT: foes or friends in detecting significant lesions in high-risk NSTE-ACS patients?

Background Coronary computed tomography angiography (CCTA) and fractional flow reserve derived from CCTA (FFR-CT) have shown potential for ruling out significant coronary lesions in patients with high-risk non-ST-elevation acute coronary syndromes (NSTE-ACS). In an international multicenter core lab-adjudicated study aimed to compare CCTA and FFR-CT independently, these modalities have shown potential for ruling out significant coronary lesions in patients with high-risk NSTE-ACS. This study demonstrated that FFR-CT had a better sensitivity than CCTA, achieving a maximum sensitivity of 87%. However, combining the strengths of both approaches may further enhance diagnostic performance. Purpose To enhance diagnostic accuracy by combining the strengths of CCTA and FFR-CT. Methods This sub-study examined cases where FFR-CT yielded false negatives, meaning invasive FFR detected significant lesions despite a negative FFR-CT result and assessed whether plaque characteristics observed on CCTA could account for these discrepancies. Results Among 459 vessels assessed, 141 lesions were classified as significant by invasive FFR, of which 117 were detected by FFR-CT, leaving 24 lesions undetected. Interestingly, 20 of these missed lesions occurred in segments where a plaque was described on CCTA. Among all plaque characteristics, 5 were associated with FFR-CT errors. When FFR-CT results were negative but the score based on these 5 parameters was pathological, reclassifying the lesion as positive improved sensitivity from 87% to 96% (Figure 1). Conclusions FFR-CT and CCTA can complement each other. Incorporating plaque characteristics from CCTA into the interpretation of FFR-CT results significantly enhances diagnostic accuracy, potentially reducing missed significant lesions.