Coronary Artery Disease (CAD) is the main cause of death worldwide, a pathological condition characterized by a reduction in blood flow to the heart. It is primarily caused by atherosclerosis, which consists of accumulation of cholesterol and fatty substances, leading to plaque formation and vessel occlusion. Given its potentially fatal consequences, accurate clinical evaluation is essential. For many years, anatomical evaluation with coronary angiography has been the main diagnostic technique; however, it presents limitations in the functional assessment of the stenosis. In this regard, physiological indices, based on the evaluation of coronary blood flow and pressure have been developed. The Fractional Flow Reserve (FFR) is a pressure-based index, that indicates the functional severity of stenosis, and allows to distinguish ischemic (FFR ≤ 0.8) and not ischemic lesions (FFR > 0.8).