Instantaneous Wave-Free Ratio-Guided vs Angiography-Guided Coronary Artery Bypass Grafting: 36-Months Graft Patency and Clinical Outcomes of a Randomized Trial

Background: Coronary artery bypass grafting (CABG) to physiologically non-significant coronary artery stenosis may result in graft failure due to competitive native flow. We evaluated whether an instantaneous wave-free ratio (iFR)-guided revascularization strategy improves graft patency and clinical outcomes compared to conventional angiography-guided CABG. Methods: In this prospective, randomized, single-blinded trial, patients with multivessel disease and at least one angiographically intermediate stenosis (50%-75%) were randomized to either CABG guided by angiography alone or angiography supplemented with iFR assessment groups. The primary endpoint was graft patency (occlusion or hypoperfusion of the graft) evaluated by coronary computed tomography angiography (CCTA) at 2, 12, and 36 months. Results: At 36 months, 78% of the patients completed follow-up. Left internal mammary artery (LIMA)-to-left anterior descending (LAD) artery graft patency was significantly higher in the iFR-guided group than in the angiography-guided group (80.5% vs. 56.8%; absolute risk difference, 23.7% [95% CI, 3.7%-43.8%]; RR, 1.42 [95% CI, 1.03-1.95]; P = 0.03). Saphenous vein graft patency also improved with iFR guidance (90.2% vs. 70.3%; P = 0.046). Major adverse cardiac and cerebrovascular events (MACCE) were similar between groups (28% vs. 20%; RR, 1.40 [95% CI, 0.69-2.85]; P = 0.48). Conclusions: iFR-guided CABG advocates significantly improved mid-term graft patency compared with angiography-guided CABG by optimizing surgical target selection and reducing competitive flow.