Complete Revascularization Versus Culprit Lesion Only in Patients With ST-Segment Elevation Myocardial Infarction and Multivessel Disease: A DANAMI-3–PRIMULTI Cardiac Magnetic Resonance Substudy

Objectives: The aim of this study was to evaluate the effect of fractional flow reserve (FFR)–guided revascularization compared with culprit-only percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) on infarct size, left ventricular (LV), function, LV remodeling, and the presence of nonculprit infarctions. Background: Patients with STEMI with multivessel disease might have improved clinical outcomes after complete revascularization compared with PCI of the infarct-related artery only, but the impact on infarct size, LV function, and remodeling as well as the risk for periprocedural infarction are unknown. Methods: In this substudy of the DANAMI-3 (Third Danish Trial in Acute Myocardial Infarction)–PRIMULTI (Primary PCI in Patients With ST-Elevation Myocardial Infarction and Multivessel Disease: Treatment of Culprit Lesion Only or Complete Revascularization) randomized trial, patients with STEMI with multivessel disease were randomized to receive either complete FFR-guided revascularization or PCI of the culprit vessel only. The patients underwent cardiac magnetic resonance imaging during index admission and at 3-month follow-up. Results: A total of 280 patients (136 patients with infarct-related and 144 with complete FFR-guided revascularization) were included. There were no differences in final infarct size (median 12% [interquartile range: 5% to 19%] vs. 11% [interquartile range: 4% to 18%]; p = 0.62), myocardial salvage index (median 0.71 [interquartile range: 0.54 to 0.89] vs. 0.66 [interquartile range: 0.55 to 0.87]; p = 0.49), LV ejection fraction (mean 58 ± 9% vs. 59 ± 9%; p = 0.39), and LV end-systolic volume remodeling (mean 7 ± 22 ml vs. 7 ± 19 ml; p = 0.63). New nonculprit infarction occurring after the nonculprit intervention was numerically more frequent among patients treated with complete revascularization (6 [4.5%] vs. 1 [0.8%]; p = 0.12). Conclusions: Complete FFR-guided revascularization in patients with STEMI and multivessel disease did not affect final infarct size, LV function, or remodeling compared with culprit-only PCI.