Hybrid Ifr-FFR Decision-Making Strategy: Implications for Enhancing Universal Adoption of Physiology-Guided Coronary Revascularization

The instantaneous wave-free ratio (iFR) for evaluation of non-culprit lesions in patients with acute coronary syndrome and multivessel disease

“…2). In line with previous results from other groups, we found that iFR was lower than FFR in 7 cases (6%) [15][16][17][18][19][20][21]. In particular, 6 of those 7 cases were registered in the ACS group (7.7% of total ACS lesions).…”

“…In particular, agreement between the two methods was higher than 90% outside the intermediate interval of iFR and FFR, with concentration of small differences around the diagnostic cutoff zone [16]. Furthermore, a recent study reports that disagreement with FFR within the clinically relevant upper range of iFR (negative tests), was not higher than 3.1% of the overall population, with over 60% of those cases falling within the FFR gray zone of 0.75-0.80 [18]. On the other hand, further studies did not achieve similar good results with iFR compared to FFR [19,20].…”

“…Recent studies [15][16][17][18] showed a good degree of agreement between iFR and FFR. In particular, agreement between the two methods was higher than 90% outside the intermediate interval of iFR and FFR, with concentration of small differences around the diagnostic cutoff zone [16].…”

“…Since most classification disagreement was concentrated around the diagnostic cutoff, study results were additionally analyzed using a "hybrid approach", according to previously described methodology [18]. In other words, two different prospective cutoffs were used: one for a positive iFR test and another one for a negative test: when iFR fell between 0.86 and 0.94, FFR was calculated.…”

“…In an attempt to overcome those restraints, an alternative adenosinefree index of coronary stenosis, the instantaneous wave-free ratio (iFR), was recently introduced in patients with stable coronary disease to assess the stenosis severity [15][16][17][18], although the value of this index has been questioned [19,20]. An independent, core laboratory-based analysis of all previous studies showed a classification match between 80 and 88% [21].…”