Fractional flow reserve (FFR)

• Fractional flow reserve (FFR) is an index of the physiological significance of a coronary stenosis
  • defined as the ratio of maximal blood flow in a stenotic artery to normal maximal flow
    • can be easily measured during coronary angiography by calculating the ratio of distal coronary pressure measured with a coronary pressure guidewire to aortic pressure measured simultaneously with the guiding catheter
    • FFR in a normal coronary artery equals 1.0
    • FFR value of 0.80 or less identifies ischaemia-causing coronary stenoses with an accuracy of more than 90%
    • information provided by FFR is similar to that obtained with myocardial perfusion studies, but it is more specific and has a better spatial resolution, because every artery or segment is analyzed separately, and masking of one ischemic area by another, more severely ischemic, zone is avoided
  • a study compared patients assigned to angiography-guided PCI (underwent stenting of all indicated lesions) compared to those assigned to FFR-guided PCI underwent stenting of indicated lesions only if the FFR was 0.80 or less
    • study showed that in patients with multivessel coronary artery disease, routine measurement of FFR during PCI, as compared with the standard strategy of PCI guided by angiography, significantly reduced the rate of the primary composite end point of death, myocardial infarction, and repeat revascularization at 1 year. The combined rate of death and myocardial infarction was also significantly reduced (2)

Reference:

• 1. Lima RS et al. Incremental value of combined perfusion and function over perfusion alone by gated SPECT myocardial perfusion imaging for detection of severe three-vessel coronary artery disease. J Am Coll Cardiol 2003;42:64-70
• 2. Torino PA et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention.N Engl J Med. 2009 Jan 15;360(3):213-24