Vessel-Specific Differences in Fractional Flow Reserve Among Intermediate Coronary Lesions

Background/Objectives: Fractional flow reserve (FFR) is the reference standard for assessing the functional significance of intermediate coronary stenoses and guiding revascularization. Although a universal ischemic threshold is applied to all epicardial vessels, potential physiological differences between coronary territories remain insufficiently explored. The aim of this study was to evaluate whether the functional significance of intermediate coronary stenoses differs according to coronary artery and to assess the clinical outcomes of FFR-guided deferral across coronary territories. Methods: This single-center retrospective study included patients who underwent single-vessel FFR assessment for angiographically intermediate lesions between 2019 and 2022. Patients with left main disease or multivessel physiological assessment were excluded. Clinical characteristics, FFR values, and long-term outcomes were analyzed according to the investigated coronary artery. Major adverse cardiovascular events (MACE) were defined as a composite of death, myocardial infarction, and urgent revascularization. Results: A total of 310 patients (corresponding to 310 coronary arteries) were included: 211 LAD, 68 RCA, and 31 LCX lesions. Overall, 18.7% of lesions had a positive FFR (≤0.80). The only variable identified in univariable analysis as being associated with FFR positivity was the coronary artery evaluated (p < 0.001). Positive FFR values were observed in 24.6% of LAD lesions, compared with 8.8% in the RCA and none in the LCX. Among patients with negative FFR for whom revascularization was deferred, five-year MACE-free survival was similar across coronary territories (p = 0.12). Conclusions: The functional significance of intermediate coronary stenoses varies according to the coronary territory, with LAD lesions more frequently reaching ischemic thresholds. However, deferral of revascularization based on negative FFR is associated with favorable long-term outcomes across all vessels, supporting a vessel-specific physiological interpretation of coronary stenoses.