ILIAS registry is a global effort to gather lesion-level data on the diagnostic and prognostic value of combined coronary pressure and flow measurements in clinical practice. Data is gathered from 7 nations (The Netherlands, Korea, Japan, Spain, Italy, Denmark, USA), using either coronary Doppler velocity measurements or coronary thermodilution measurements to obtain invasive coronary flow assessment. Patient treatment was governed by the local clinical practice guidelines at the time of the invasive procedure, but was at the operator's discretion. A standardized data collection sheet was used and all study adopted standardized definition of patient's baseline characteristics, clinical outcomes, and physiologic data. In case of acute coronary syndrome (unstable angina, non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction), only non-culprit vessel evaluation was used.