In patients with STEMI and with multivessel disease, complete revascularization guided by fractional flow reserve (FFR) did not have significant benefit over an angiography-guided strategy in terms of risk of death, myocardial infarction (MI) or urgent revascularization at one year, based on findings from the FLOWER-MI trial presented May 16 during ACC.21 and simultaneously published in the New England Journal of Medicine.

The trial, conducted at 41 centers in France, randomized 1,171 patients who had undergone successful PCI of the infarct-related artery to receive either complete revascularization guided by FFR or angiography. The second procedure was performed within five days of the first during the same hospitalization. On average, patients were 62 years of age and 83% were men.

After 12 months, 5.5% of patients in the FFR-guided group had died, had another non-fatal MI or had undergone an additional stenting procedure, compared with 4.2% of those in the angiography-guided group, a non-statistically significant difference (hazard ratio, 1.32, 95% confidence interval, 0.78 to 2.23; p=0.31). As such, the study failed to meet its primary endpoint, a composite of death from any cause, non-fatal MI, or urgent need for an additional stenting procedure within 12 months. However, researchers noted that given the wide confidence intervals for the estimate of effect, the findings do not allow for conclusive interpretation.

In other findings, the incidence of major adverse cardiovascular events in both groups of patients was considerably lower than the researchers expected at 5% at one year. A secondary endpoint looking at cost-effectiveness favored the use of angiography alone. However, the cost-effectiveness analysis was based on the costs of the two treatment approaches in France and might not be applicable in other countries, Puymirat said.

"The strategy of using FFR to guide the stenting procedure is not superior to the standard technique of using angiography to treat additional partially blocked arteries," said Etienne Puymirat, MD, principal investigator of the study. "In addition to having no benefit, we have also shown that, based on costs in France, the FFR-guided strategy is more expensive."

Researchers will continue to follow the patients in the study for another two years.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Vascular Medicine, Interventions and ACS, Interventions and Imaging, Interventions and Vascular Medicine, Angiography, Nuclear Imaging, Chronic Angina

Keywords: ACC Annual Scientific Session, ACC21, Percutaneous Coronary Intervention, Acute Coronary Syndrome, Angiography, ST Elevation Myocardial Infarction

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