Comparison Between Non-invasive (Coronary Computed Tomography Angiography Derived) and Invasive-Fractional Flow Reserve in Patients with Serial Stenoses Within One Coronary Artery: A NXT Trial substudy.

Fractional flow reserve (FFR) has been established as gold standard to detect hemodynamically significant coronary artery disease. Non-invasive FFR derived from coronary computed tomography angiography (CTA; FFRCT) has demonstrated higher diagnostic performance compared with FFR. However, the accuracy and potential advantages of FFRCT compared with invasive FFR in coronary arteries with serial lesions have not been examined. The aim of this study was to compare trans-lesional gradient in FFRCT to that in invasive FFR in coronary arteries with serial stenoses. Eighteen vessels with serial coronary lesions from 18 stable angina patients were evaluated with angiography, FFR, and coronary CTA. FFRCT was computed from 3-dimensional CT model and coronary flow dynamics data. Multiple FFRCT values were co-registered with measured FFR across the lesions, and trans-lesional delta were compared between FFRCT and FFR. The mean values of the most distal FFR and FFRCT in the same co-registered regions were 0.72 ± 0.10 and 0.69 ± 0.11, respectively. In 13 vessels (72.2%), FFR was ≤0.80, while in 14 vessels (77.8%), FFRCT was ≤0.80. Trans-lesional delta FFR and FFRCT were 0.10 ± 0.09 and 0.09 ± 0.10 in distal segments, while 0.17 ± 0.10 and 0.22 ± 0.13 in proximal segments, respectively. The coefficient of correlation between trans-lesional delta FFR and FFRCT in each segment was 0.92 (p < 0.001). Trans-lesional delta FFR and FFRCT show an excellent correlation. Further studies are required to determine the diagnostic accuracy and clinical impact of our findings.