Compared Outcomes of ST-Segment–Elevation Myocardial Infarction Patients With Multivessel Disease Treated With Primary Percutaneous Coronary Intervention and Preserved Fractional Flow Reserve of Nonculprit Lesions Treated Conservatively and of Those With Low Fractional Flow Reserve Managed Invasively: Insights From the FLOWER-MI Trial

Abstract

Background: In patients with ST-elevation myocardial infarction (STEMI) and multivessel disease, percutaneous coronary intervention (PCI) for non-culprit lesions guided by FFR is superior to treatment of the culprit lesion alone. Whether deferring non-culprit PCI is safe in this specific context is questionable. We aimed to assess clinical outcomes at one-year in STEMI patients with multivessel coronary artery disease and an FFR-guided strategy for non-culprit lesions, according to whether or not ≥1 PCI was performed. Methods: Outcomes were analyzed in patients of the randomized FLOWER MI (Flow Evaluation to Guide Revascularization in Multivessel ST-Elevation Myocardial Infarction) trial in whom, after successful primary PCI, non-culprit lesions were assessed using FFR. The primary outcome was a composite of all-cause death, non-fatal MI, and unplanned hospitalization with urgent revascularization at one year. Results: Among 1,171 patients enrolled in this study, 586 were assigned to the FFR-guided group: 388 (66%) of them had ≥1 PCI and 198 (34%) had no PCI. Mean FFR before decision (i.e., PCI or not) of non-culprit lesions were 0.75±0.10 and 0.88±0.06, respectively. During follow-up, a primary outcome event occurred in 16 of 388 patients (4.1%) in patients with PCI and in 16 of 198 patients (8.1%) in patients without PCI (adjusted hazard ratio, 0.42; 95% confidence interval, 0.20 to 0.88; P = 0.02). Conclusions: In patients with STEMI undergoing complete revascularization guided by FFR measurement, those with ≥1 PCI had lower event rates at 1 year, compared with patients with deferred PCI, suggesting that deferring lesions judged relevant by visual estimation but with FFR >0.80 may not be optimal in this context. Future randomized studies are needed to confirm this data.

The year in cardiovascular medicine 2021: interventional cardiology

“…Subsequently, a substudy of the FLOWER-MI found that patients in the FFR guidance arm with ≥1 PCI had lower event rates at 1 year, compared with patients with a deferred PCI. 4 These findings align with a recent large patient-level metanalysis 5 ( n = 8579) that found increased event rates associated with an FFR-based deferral of revascularization of NCLs in ACS, compared with stable patients, pointing to either suboptimal performance of non-culprit FFR in STEMI patients or a protective effect of PCI in NCLs with rupture-prone vulnerable plaques. Overall, PCI of severely stenotic NCLs in ≥2.0 mm diameter arteries is indicated for STEMI patients, regardless of the FFR status, when technically feasible.…”

Angiography versus FFR guided complete revascularization versus culprit‐only revascularization for patients presenting with STEMI: Network meta‐analysis

“…In a subset analysis of the FLOWER MI trial, patients who underwent PCI for 1 or more non-culprit stenoses had lower event rates at 1 year, compared with patients with deferred PCI based on a FFR > 0.80, suggesting that deferring lesions that appear significant by visual estimation but with FFR > 0.80 in the setting of STEMI may not be the correct course of action. 27 Lee et al 28 reported that non-culprit stenoses in patients with an FFR > 0.8 in patients with ACS were associated with more than twofold higher rate of MACE than non-culprit stenoses with FFR > 0.8 in patients with stable coronary disease. Those findings are also consistent with our understanding of the pathobiology of vulnerable plaque whereby plaque volume, composition and dynamic behavior is more important than stenosis physiologic severity in predicting MI, particularly in vulnerable patients.…”

“…Our findings are consistent with the preponderance of evidence regarding the limited utility of FFR guided revascularization of non‐culprit stenoses in patients with STEMI. In a subset analysis of the FLOWER MI trial, patients who underwent PCI for 1 or more non‐culprit stenoses had lower event rates at 1 year, compared with patients with deferred PCI based on a FFR > 0.80, suggesting that deferring lesions that appear significant by visual estimation but with FFR > 0.80 in the setting of STEMI may not be the correct course of action 27 . Lee et al 28 reported that non‐culprit stenoses in patients with an FFR > 0.8 in patients with ACS were associated with more than twofold higher rate of MACE than non‐culprit stenoses with FFR > 0.8 in patients with stable coronary disease.…”

Response by Puymirat and Danchin to Letter Regarding Article, “Compared Outcomes of ST-Segment–Elevation Myocardial Infarction Patients With Multivessel Disease Treated With Primary Percutaneous Coronary Intervention and Preserved Fractional Flow Reserve of Nonculprit Lesions Treated Conservatively and of Those With Low Fractional Flow Reserve Managed Invasively: Insights From the FLOWER-MI Trial”

“…Cerrato and Escaned report that the conclusions of their patient-level meta-analysis of cohorts of patients with either stable angina pectoris or acute coronary syndrome in whom percutaneous coronary intervention was deferred on the basis of fractional flow reserve measurements are in line with our findings from the FLOWER-MI trial (FLOW Evaluation to Guide Revascularization in Multi-Vessel ST-Elevation Myocardial Infarction). [1][2][3] In fact, in patients with deferred percutaneous coronary intervention, they observed a higher major adverse cardiac events (MACE) rate after acute coronary syndrome, compared with MACE occurring in stable patients (hazard ratio, 1.72 [95% CI, 1.17-2.53]); however, in contrast with what we observed, MACE rates were lower in patients with acute coronary syndrome with deferred percutaneous coronary intervention (52/1166, 4.46%) versus those in whom percutaneous coronary intervention was actually performed (62/952, 6.51%; Table ). We, therefore, do not understand why the authors now conclude from their analysis that deferring revascularization in nonculprit lesions with fractional flow reserve >0.80 was associated with an increased risk of events.…”