Performing instantaneous wave-free ratio (iFR) guided percutaneous coronary intervention (PCI) on non-culprit lesions during the initial revascularization procedure for ST-segment elevation myocardial infarction (STEMI) with multivessel disease (MVD) did not reduce major adverse cardiac events (MACE) versus deferred procedures at 3 years, the iMODERN randomized superiority trial found.