Beyond the Numbers: The Challenge of FFR-Guided Strategies in Multivessel Disease Undergoing CABG – Think Differently

Background Fractional Flow Reserve (FFR) is a cornerstone in guiding percutaneous coronary intervention (PCI) for intermediate coronary lesions, supported by robust evidence and guidelines. Its application in coronary artery bypass grafting (CABG), however, remains uncertain, with no validated thresholds or standardized integration into surgical planning. Case Summary We report the case of a 69-year-old man with three-vessel coronary artery disease who underwent total arterial revascularization using a bilateral internal mammary artery Y-graft. Despite a preoperative FFR of 0.78 in the left anterior descending artery (LAD), intraoperative transit-time flow measurements (TTFM) revealed severely impaired graft flow, prompting revision of the LIMA–LAD anastomosis. Post-revision flow remained poor. At three-month follow-up, angiography confirmed graft failure, yet myocardial perfusion imaging showed no significant ischemia in the LAD territory. Discussion This case underscores the limitations of applying FFR as a primary determinant in surgical revascularization. In the absence of validated cutoffs for CABG, reliance on PCI-based thresholds may lead to inappropriate grafting strategies, competitive flow, and early graft failure. FFR should be seen as a physiological adjunct—not a directive—within a broader framework of clinical, anatomical, and intraoperative assessment. Current evidence does not support replacing angiographic judgment with FFR in surgical decision-making. The integration of FFR into CABG planning requires a nuanced, individualized approach, guided by future trials and multidisciplinary expertise. Conclusion In surgical revascularization, the question is not whether a lesion crosses an FFR threshold, but how to best achieve durable myocardial protection.