Novel cardiac computed tomography-based preoperative indicator associated with intraoperative graft flow in coronary artery bypass grafting

Background: Graft flow in coronary artery bypass grafting (CABG) is linked with blood distribution of the target vessel. In this study, we aimed to develop a novel quantitative measurement of target coronary artery quality using coronary computed tomography angiography (CCTA) and investigate its correlation with intraoperative transit time flow measurement (TTFM).

Methods: We enrolled 68 patients with CABG who underwent preoperative CCTA. Target coronary artery volume index (TCAVI) was calculated from CCTA images and measurements in 65 arterial and 94 venous bypass grafts. CCTA-TCAVI, representing total volume (mm³) of arterial vasculature per individual target artery, was statistically analyzed for correlation with TTFM.

Results: CCTA-TCAVI demonstrated a positive correlation with mean graft flow (MGF=0.222, p=0.005). TCAVI was linked with abnormal internal mammary artery grafts (intraoperative mean graft flow <20 mL/min and PI 5) and saphenous vein grafts (SVG, <40 mL/min) and pulsatility Index (PI 5) odds ratio (OR=0.99, <1, p=0.004). Interquartile range analysis revealed a significant correlation between abnormal SVG and TCAVI (p<0.001), but no correlation between abnormal internal mammary artery (IMA) and TCAVI (p=0.912). Compared with previous predictive measurements, TCAVI correlated with graft flow(MGF=0.222, p=0.005). The cutoff value for CCTA-TCAVI was 200 mm³. Compared with coronary stenosis percentage, TCAVI prediction accuracy was 13% higher.

Conclusions: TCAVI as a novel measurement may be useful to appropriately select the optimal target arteries at the time of CABG. It may have clinical potential to predict intraoperative abnormal venous grafts with high accuracy.