Reviwer  : Dr. Dursun AKASLAN

Name of study : FLOWER-MI (Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction)

Published in congress : ACC21

Fulltext linki: https://www.nejm.org/doi/full/10.1056/NEJMoa2104650

Background :
Many studies have shown that FFR is superior to angiography in patients with chronic coronary syndrome. In patients with ST elevation myocardial infarction, it was shown in the DANAMI3-PRIMULTI study that FFR-guided complete revascularization was more successful in only infarct related lesion revascularization. Comparison of FFR and angiography guided  total revascularization of patients with  STEMI and multivessel disease has not been made.

Objective :
The aim of the FLOWER MI study was to investigate whether the use of FFR in complete revascularization provides a better clinical outcome than the use of angiography guided revascularization in STEMI patients .

Methods :
In this multicenter study, patients with STEMI and multivessel disease who were scheduled for FFR or angiography-guided complete revascularization and who underwent successful PCI to the infarct-related artery were randomized. The primary outcome was death from any cause, non-fatal myocardial infarction, or unplanned hospitalization leading to emergency revascularization at 1 year. 1183 patients who applied to 41 different centers in France were included in the study. Of these, 586 patients underwent FFR-guided percutaneous intervention, while 577 patients underwent angiography-guided percutaneous intervention. During follow-up, the primary outcome occurred in 32 (5.5%) of 586 patients in the FFR-guided group and 24 (4.2%) of 577 patients in the angiography-guided group (HR, 1.32; 95% CI 0.78 to 2.23; P=0.31). FFR-guided death occurred in 9 (1.5%) and angiography-guided 10 (1.7%) patients; non-fatal myocardial infarction in 18 (3.1%) and 10 (1.7%) respectively; and emergency revascularization due to unplanned hospitalization occurred in 15 (2.6%) and 11 (1.9%), respectively. 

Conclusion :  
This study demonstrated that an FFR-guided strategy had no significant benefit over an angiography-guided strategy in terms of the risk of death, myocardial infarction, or urgent revascularization at 1 year in STEMI patients undergoing complete revascularization.

Interpretation :
Given the wide confidence intervals for the effect estimation in this study, the findings do not allow for a definitive interpretation. However, when we look at the rates of percutaneous intervention for non-responsible lesions, the number of stents used under FFR guidance was 1.01±0.99, while the number of stents used under angiography guidance was 1.50±0.86. Although the FFR procedure is still considered to be a costly procedure, I think the reduction in the number of stents used will reduce the cost and make the patient at lower risk for long-term stent restonosis.