TCT-300 FFRCT-Derived Coronary Physiological Pattern and Graft Patency in the FASTTRACK CABG Trial

Abstract

Background
Pullback pressure gradient (PPG) can quantify the physiologic patterns (focal or diffuse CAD phenotypes) of coronary artery disease (CAD). For extensive and diffuse CAD, coronary artery bypass graft (CABG) is the recommended treatment. However, whether CAD pattern affects graft patency remains elusive. We aimed to evaluate the association between graft patency and PPG derived from coronary computed tomography angiography (CCTA) fractional flow reserve (FFRCT).

Methods
Patients with 3-vessel or left main CAD were included in the FASTTRACK CABG trial (n = 114). Before CABG, the PPG, FFRCT, and highest delta FFRCT per millimeter (dFFRCT/ds) of the grafted vessel without total occlusion were assessed. Graft patency was assessed with a 30-day follow-up CCTA.

Results
Among the 96 patients, 260 grafts (158 arterial, 91 venous, and 11 composite grafts) were analyzed. At 30 days, 22 grafts occluded. Vessels with graft occlusion have higher FFRCT (0.71 [0.63-0.83] vs 0.62 [0.5-0.75]; P = 0.025) and lower dFFRCT/ds (0.05 [0.03-0.08] vs 0.08 [0.04-0.15]; P = 0.016) than vessels with patent grafts; but the PPGs were similar (0.61 ± 0.11 vs 0.64 ± 0.14; P = 0.373) (Figure 1). The AUCs for predicting graft occlusion were 0.667 (95% CI: 0.532-0.803), 0.681 (95% CI: 0.574-0.789), and 0.567 (95% CI: 0.438-0.697) for FFRCT, dFFRCT/ds, and PPG, respectively (Figure 2).

Conclusions
Diffuse CAD indicated by low PPG is not associated with graft occlusion, whereas FFRCT and dFFRCT/ds can identify occlusion-prone vessels. This suggests that CABG is a viable revascularization option for diffuse CAD patients.