Clinical InvestigationInstantaneous wave-free ratio and fractional flow reserve for the assessment of nonculprit lesions during the index procedure in patients with ST-segment elevation myocardial infarction: The WAVE study

BackgroundFunctional assessment of non-infarct-related artery lesions during primary percutaneous coronary intervention (PCI) might be useful to avoid revascularization of nonsignificant stenosis and staged procedures, thus reducing hospital stay. We aimed to assess the diagnostic performance of instantaneous wave-free ratio (iFR) as compared with fractional flow reserve (FFR) in this setting.MethodsIn the WAVE study, a prospective, observational, single-center registry (NCT02869906), paired iFR and FFR measurements were performed at the level of non-IRA lesions in patients with ST-segment elevation myocardial infarction both during primary PCI and during staged procedures (5-8 days after).ResultsPaired iFR and FFR measurements were available for 66 non-IRA lesions in 50 patients. The iFR and FFR values of non-IRA lesions did not change significantly between the index and staged procedure. Bland-Altman analysis did not show systematic bias for either iFR or FFR repeated measures. Receiver operating characteristic curve analysis showed high accuracy of iFR to identify positive (≤0.80) FFR measurements in the index procedure with an area under the curve of 0.95. A cutoff of ≤0.89 for iFR in the index procedure had the best combination of sensitivity (95%) and specificity (90%) with positive and negative predictive values of 86% and 97%, respectively. Finally, iFR measured during the index procedure was significantly correlated with FFR (r = 0.71, r2 = 0.51; P < .0001).ConclusionsThe WAVE study shows that iFR yields similar diagnostic accuracy to FFR in functional evaluation of non-IRA stenosis in patients with STEMI and multivessel CAD, with the advantage of being adenosine free.