FLOWER-MI: FFR-guided PCI for STEMI Yields No Additional Benefit

The use of fractional flow reserve (FFR)-guidance for coronary stenting after an ST-segment elevation myocardial infarction (STEMI) did not add benefit, according to new study results presented at the American College of Cardiology Scientific Sessions (ACC.21).

Researchers for the Fractional Flow Reserve-guided Versus Angio-guided Multivessel Revascularization In ST-Elevation Myocardial Infarction Patients (FLOWER-MI) trial enrolled 1,171 patients who had received stents following STEMI and with a second coronary artery that was at least 50% blocked. Following the first procedure, the second was performed within 5 days, and was guided by either FFR or or with angiography. The primary study outcome was composite death from any cause, nonfatal myocardial infarction (MI), or unplanned hospitalization leading to urgent revascularization at 1 year.

According to the results, the primary endpoint occurred in 5.5% of patients in the FFR-guided arm and 4.2% of the angiography arm (HR=1.32; 95% CI, 0.78 to 2.23; P=0.31). Similar rates between study groups were observed for death (1.5% FFR vs. 1.7% angiography), nonfatal MI (3.1% FFR vs. 1.7% angiography), and unplanned hospitalization (2.6% FFR vs. 1.9% angiography).

“The strategy of using fractional flow reserve (FFR) to guide the stenting procedure is not superior to the standard technique of using angiography to treat additional partially blocked arteries,” principal investigator Etienne Puymirat, MD, professor of cardiology at the University of Paris, director of intensive care at the Georges Pompidou Hospital in Paris, said in a news release. “In addition to having no benefit, we have also shown that, based on costs in France, the FFR-guided strategy is more expensive.”

He added the rates for major adverse cardiovascular events were significantly lower than the authors had expected.

“These patients were at high cardiovascular risk because of having multi-vessel disease,” he said. “Using data from previous trials and registries in this population, we estimated that about 15% of patients would have an adverse event within one year, but in our study the rate was 5% at one year.”

The study was simultaneously published in the New England Journal of Medicine.

Puymirat E. Fractional flow reserve-guided versus angio-guided multivessel revascularization in ST-elevation myocardial infarction patients: The FLOWER-MI randomized trial. Presented at: American College of Cardiology Scientific Sessions; May 15-17, 2021.