The assessment of Left Main Coronary Artery (LMCA) lesions by means of coronary angiography renders serious limitations. In the case of intermediate stenoses (25-60%), invasive imaging tests, intravascular ultrasound (IVUS) or optical coherence tomography (OCT) or functional by determining the Fractional Flow Reserve (FFR), have been proposed to identify those patients who could benefit from revascularization.~Studies with a limited number of patients have shown that a value of FFR above 0.80 identify a low risk of events in case of not performing revascularization in patients with intermediate stenosis in the LMCA. Although iFR (Instant wave Free Ratio) has recently been found equivalent to FFR in assessing the prognosis of patients with intermediate lesions, the validation of the prognostic power of this index in patients with intermediate LMCA lesions has not been demonstrated, although it is used in clinical practice assuming the results in other locations of the lesions.~The demonstration of the prognostic utility of iFR in patients with LMCA intermediate lesions could have an important clinical impact and justify its systematic use for the treatment decision in these high-risk patients.
The assessment of Left Main Coronary Artery (LMCA) lesions by means of coronary angiography renders serious limitations.~Studies with a limited number of patients have shown that a value of FFR (Fractional Flow Reserve) above 0.80 identify a low risk of events in case of not performing revascularization in patients with intermediate stenosis in the LMCA. Although iFR (Instant wave Free Ratio) has recently been found equivalent to FFR The demonstration of the prognostic utility of iFR in patients with LMCA intermediate lesions could have an important clinical impact and justify its systematic use for the treatment decision in these high-risk patients.