Fractional flow reserve: a clinical perspective

Fig. 1. Schematic representation of the comprehensive assessment of the structural and functional components of the epicardial and microvascular compartments of the coronary tree. CFR represents the vasodilatory capacity of the epicardial vessel being interrogated and the microvasculature that it subtends. FFR is the reference standard for the assessment of the functional significance and an epicardial coronary stenosis. The IMR is a specific measure or the microvascular resistance being interrogated. Endothelial function, and epicardial and microvascular spasm may be tested for with vasoreactivity testing. FFR fractional flow reserve, IMR index of microcirculatory resistance, CFR coronary flow reserve

Fig. 2. Schematic representation of fractional flow reserve measurement. Pa proximal (aortic) pressure, Pd distal coronary pressure

Fig. 3. a FFR recording demonstrating the interrogation of a significant coronary lesion with an FFR value below the clinical ischaemic threshold of 0.8. b Measurement of a coronary wedge pressure. c Pull-back assessment for pressure wire ‘drift’ following FFR measurement

Fig. 4. Pyramid of diagnostic accuracy with invasive assessments of coronary physiology. Adapted from Johnson et al. [63]

Fig. 5. Indications for the use on FFR-guided care in the diagnostic and invasive management of patients with stable CAD, and the relevant completed and ongoing FFR-guided clinical trials (black boxes), MR-INFORM [102], CE-MARC2 [103], RIPCORD [62], RIPCORD-2 [70], COURAGE [71], ISCHEMIA, DEFER [21], FAME [22], FAME-2 [23], FAME-3