Objective. In this multicentre study, we investigated the long-term prognostic value of intracoronary derived haemodynamic parameters compared with the results of myocardial perfusion scintigraphy (MPS). Keywords: coronary artery disease, myocardial perfusion scintigraphy, coronary flow velocity reserve, fractional flow reserve, angioplasty, risk stratification A dequate patient selection for percutaneous transluminal coronary angioplasty (PTCA) is important in view of the potential procedural complications and the incidence of restenosis. Assessment of the functional significance of coronary lesions is mandatory, especially in intermediate coronary narrowings (40 to 70% diameter stenosis). Assessment can be performed noninvasively (using myocardial perfusion scintigraphy; MPS) 1 or invasively during cardiac catheterisation using intracoronary derived haemodynamic indices. 2 Previous validation studies have shown good agreement (80 to 90%) between these parameters and the results of noninvasive stress tests. [3][4][5] Previously, we reported the final results of the ILIAS (Intermediate Lesions: Intracoronary flow Assessment versus 99m Tc-MIBI SPECT) study with one-year clinical follow-up. 6 In this multicentre study, we directly compared the value of intracoronary derived coronary flow velocity reserve (CFVR) with myocardial perfusion scintigraphy in the context of clinical decision-making in patients with an intermediate lesion and multivessel coronary artery disease. We concluded that deferral of PTCA of intermediate lesions in multivessel disease is safe when the CFVR is ≥2.0 (event rate 6%); a threefold increase of cardiac events was observed when PTCA was deferred despite a CFVR <2.0. This selective evaluation of coronary lesion severity during cardiac catheterisation allows more accurate risk stratification than MPS, which is