Mika Noda, Yoshiyuki Takami, Kentaro Amano, Yusuke Sakurai, Kiyotoshi Akita, Atsuo Maekawa, Yasushi Takagi
The Annals of thoracic surgery, Jun 9, 2020
BACKGROUND: Transit-time flow measurement (TTFM) is frequently used for intraoperative graft flow analysis during coronary artery bypass grafting (CABG). Although the TTFM results may be influenced by fractional flow reserve (FFR) of the target coronary artery as a determinant of coronary lesion-specific ischemia, the data has been limited. METHODS: We retrospectively investigated the relationships between the intraoperative TTFM parameters and preoperative FFR values of the target coronary arteries in 40 in-situ left internal thoracic artery (LITA) grafts to the left anterior descending artery (LAD), which were revealed to be patent on postoperative computed tomography angiography. RESULTS: The Spearman correlation coefficients of the TTFM parameters with FFR were as follows; maximum flow: -0.12 (p = 0.301), minimum flow (Qmin): -0.43 (p = 0.004), mean flow (Qm): -0.30 (p = 0.036), pulsatility index (PI): 0.37 (p = 0.012), diastolic filling (DF): -0.36 (p = 0.012), percent insufficiency (%Insuf): 0.45 (p = 0.002), and fast Fourier transform (FFT) ratio: -0.07 (p = 0.329). While Min and Qm showed significant negative correlation, PI and %Insuf showed significant positive correlation with FFR. CONCLUSIONS: Most TTFM parameters, including Qm, of the LITA graft to the LAD during CABG are strongly affected by preoperative FFR values. Since the FFT ratio is not influenced by FFR, FFT analysis of the TTFM may be recommend in the case of the in-situ LITA graft to the LAD with moderate stenosis with a higher FFR>0.75.