van der Hoeven NW, Janssens GN, de Waard GA, et al. - Researchers evaluated the utility of hemodynamic indices in nonculprit vessels of patients with ST-segment elevation myocardial infarction (STEMI) from the index event to 1-month follow-up in this substudy of the Reducing Micro Vascular Dysfunction in Revascularized STEMI Patients by Off-target Properties of Ticagrelor randomized clinical trial. Enrollment of 98 STEMI patients with an angiographic intermediate stenosis in at least 1 nonculprit vessel was done. The final analysis included 73 patients with STEMI with multivessel disease. Decreased nonculprit coronary flow reserve and augmented fractional flow reserve, with unaltered instantaneous wave-free ratio, were seen in the acute setting of STEMI. An increased hyperemic microvascular resistance and a blunted adenosine responsiveness at the acute moment that was related to infarct size possibly explain these findings.