OBJECTIVES: In the present study, we analyzed the clinical outcome of patients with multivessel coronary artery disease in whom at least one vessel was treated by percutaneous coronary intervention (PCI) and at least one other vessel was deferred on the basis of fractional flow reserve (FFR) measurements during the same session. BACKGROUND: Myocardial FFR is an established tool for assessing the severity of epicardial stenoses. It has been shown that it is safe to defer an intervention in single vessel disease patients when FFR >0.75. METHODS: One hundred two patients (66 ± 10 years) with multivessel coronary artery disease were included in the study. In all patients, PCI of at least two vessels was contemplated. Yet in all of them at least one vessel was treated by PCI, whereas at least one other vessel was deferred based on an FFR >0.75. Major adverse cardiac events (MACE) were recorded during an average follow-up of 29 ± 18 months. RESULTS: In 102 patients, 113 coronary arteries underwent PCI. In these arteries FFR was 0.57 ± 0.13 and mean diameter stenosis was 68 ± 14%. One hundred twenty-seven coronary arteries had an FFR >0.75 and PCI was deferred. In these arteries FFR was 0.86 ± 0.06 and mean diameter stenosis was 47 ± 12%. No death occurred during the follow-up. A MACE occurred in 9% and 13% of patients after 12 and 36 months, respectively. These MACE were related to 22 (9.2%) arteries. Among them, 8 (6.3%) MACE were related to one of the initially deferred vessels, whereas 14 (12.3%) MACE were related to one of the initially treated coronary artery. CONCLUSIONS: In patients with multivessel disease, PCI of hemodynamically non-significant stenoses can be safely deferred, even if initially planned on the basis of the angiogram.