Phd in ANGIO-CARDIO-THORACIC PATHOPHYSIOLOGY AND IMAGING

Thesis title: Preoperative Angiography-Derived Fractional Flow Reserve May Predict Bypass Graft Occlusion and Disease Progression at Mid-Term Follow-Up

Background: Graft occlusion after coronary artery bypass grafting (CABG) has been associated with competitive flow of native coronary arteries. Objectives: to assess with coronary CT angiography (CCTA) graft occlusion and coronary artery disease (CAD) progression of native vessels after CABG and their relationship with angiography-derived vessel-fractional flow reserve (vFFR) performed before surgery. Methods: Between 2008 and 2020, serial vFFR analyses were obtained before CABG in each major native coronary vessel from three institutions. All patients underwent follow-up CCTA. Results: In 171 consecutive patients, serial preoperative angiograms were suitable for vFFR analysis of 298 grafted and 59 non-grafted vessels. Median time between CABG and CCTA was 2.1 years. Preoperative vFFR was assessed in 131 LAD, 132 LCX and 94 RCA and was <0.80 in 255/298 bypassed vessels. Graft occlusion was observed at CCTA in 28/298 grafts. The median preoperative vFFR value of native coronaries was higher in occluded compared to patent grafts (0.75 vs. 0.60, p<0.001) and was associated with graft. The best vFFR cut-off to predict graft occlusion was 0.67. Progression of CAD was higher in grafted than in non-grafted vessels (89.6% vs.47.5%, p<0.001). Pre-CABG vFFR predicted disease progression of grafted native vessels (AUC=0.83). Conclusions: Preoperative vFFR derived from ICA was able to predict graft occlusion and CAD progression of grafted coronary arteries