Functional Assessment of Coronary Lesions in the Cath Lab

It is important to identify those patients that will benefit from revascularization and those patients that will have an excellent prognosis on optimal medical treatment. Thus, there is a need of an easily performed diagnostic test in the cath lab that can accurately and reliably assess the physiological significance of a coronary artery stenosis. Fractional flow reserve (FFR) is a well-established method that has been proven to measure the functional significance of a stenosis. In the absence of a stenosis FFR is 1 and decreases depending on the significance of the stenosis. Instantaneous wave-free ratio (iFR) is a recently developed physiological index, which is obtained at rest without the need of hyperemic stimulation. Several trials have demonstrated that an iFR cut point of 0.89 matches an FFR cut point of 0.80.