The INSIGHTFUL-FFR study is an investigator-driven trial in the field of invasive coronary physiology aiming at refining PCI guidance and evaluation. It is a prospective study enrolling patients with one or more coronary stenoses randomized to use of pressure microcatheter or pressure wire to guide and optimize percutaneous coronary intervention (PCI). 2500 subjects will be enrolled in up to 35 sites in the EU and China.