Quantitative Flow Ratio on Radial Artery Graft Outcome After Coronary Artery Bypass Grafting

In coronary artery bypass grafting (CABG), the use of radial artery (RA) is recommended by the guidelines only to significantly stenosed vessel, due to its high vulnerability to competitive flow. Fractional flow reserve (FFR) is the gold standard to measure physiological significance of coronary lesions and the potential for competitive flow. This study aims to investigate whether the preoperative quantitative flow ratio (QFR) measurement, a novel coronary angiography-based FFR, is associated with RA graft failure post-CABG, and to explore the best cut-off value of QFR for RA grafts using. Patients from ASRAB-pilot trial (NCT04310995) undergoing primary isolated CABG using RA grafts, and with preoperative coronary angiography (CAG) images available for QFR analysis will be enrolled in this prospective double-blind observational study. QFR analysis will be conducted for all RA-grafted vessels based on preoperative CAG. The primary outcome will RA graft failure (FitzGibbon Grade B,O or S) evaluated by coronary computer tomography angiography or CAG at 7 days and 6 months post-CABG.