Rationale and design of the Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction (FLOWER-MI) trial.

ABSTRACT

BACKGROUND: In ST-elevation myocardial infarction (STEMI) patients presenting with multivessel disease (MVD), recent studies have demonstrated the superiority of fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) for non-culprit lesions compared to culprit lesion treatment-only therapy. FFR- and angio-guided PCI have however never been compared in STEMI patients. TRIAL DESIGN: FLOWER-MI is an open-label multicenter national randomized clinical trial. The aim is to investigate FFR-guided complete revascularization in comparison to angio-guided complete revascularization in STEMI patients with successful PCI of the culprit lesion and ≥50% stenosis in at least one additional non-culprit lesion requiring PCI. Eligible patients will be randomized after successful primary PCI in a 11 fashion to either FFR-guided or angio-guided complete revascularization during the index procedure or a staged procedure before discharge (≤5 days). Patients assigned to FFR guidance first have FFR measured in each non-culprit vessel and only undergo PCI if FFR is ≤0.80. The primary end point of the study is a composite of major adverse cardiac events, including all-cause death, non-fatal MI, and unplanned hospitalization leading to urgent revascularization at 1 year. Secondary end points will include the individual adverse events, cost-effectiveness, quality of life, and 30-day, 6-month, and 3-year outcomes. Based on estimated event rates, a sample size of 1170 patients is needed to show superiority of the FFR-guided revascularization with 80% power. CONCLUSION: The aim of FLOWER-MI trial is to assess whether FFR-guided complete revascularization in the acute setting is superior angio-guided complete revascularization.