A head-to-head comparison of fractional flow reserve (FFR) and intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI) in patients with intermediate coronary artery stenosis found that FFR was non-inferior to IVUS for adverse clinical outcomes at a two-year follow-up.
This was the concluding finding of the FLAVOUR study, an investigator-initiated, prospective, randomised open-label multinational trial, which sought to assess which of the two adjunctive tools could bring about better clinical and patient-reported outcomes, presented in a late-breaking trial session at the American College of Cardiology’s annual scientific sessions (ACC 2022, 2–4 April, Washington DC, USA) by Bon-Kwon Koo (Seoul National University Hospital, Seoul, South Korea).
“Our study shows that in patients with intermediate levels of coronary arterial blockage, determining the need for a stent by measuring blood flow to the heart, rather than by the extent of arterial blockage, resulted in similar clinical outcomes, similar patient quality of life and reduced use of medical resources,” said Bon-Kwon Koo, MD, of Seoul National University Hospital in South Korea and principal investigator for the study.
FLAVOUR’s findings should encourage interventional cardiologists to consider an FFR-guided PCI first strategy for patients with intermediate coronary stenosis, Koo went on to state.
Patients were enrolled in the study if they had de novo intermediate (40–70%) and were eligible for PCI. This group of patients is most likely to need evaluation of their need for stenting, Koo said. In his presentation, Koo described FFR as an invasive physiologic index to define ischaemia-causing stenosis, whereas IVUS is an invasive imaging tool to evaluate anatomical severity and plaque characteristics, and to optimise PCI.
An outcome-based comparison trial is needed, he said, to unravel the clinical relevance of the conceptual difference between physiology-guided—FFR—and imaging-guided—IVUS—PCI. Previous studies, including some conducted in patients with intermediate coronary stenosis, had shown that both FFR-guided and IVUS-guided PCI produced better patient outcomes than angiography-guided PCI, said Koo. However, FFR-guided and IVUS-guided PCI had not been compared head-to-head.
The study enrolled 1,682 patients with intermediate coronary stenosis. The average age of patients was 65 and 71% were men. Just over half had blockages in multiple arteries supplying blood to the heart and about one-third had diabetes in addition to heart disease. Six percent of the patients had previously had a heart attack and 30% were at high risk for one.
All patients were randomly assigned to undergo evaluation for PCI using either FFR or IVUS. The decision to proceed with PCI was based on each technique’s standard criteria for doing so. In accordance with standard care after PCI, patients who received PCI took two antiplatelet medications for six to 12 months after their procedure to reduce their risk of adverse events. Patients who did not receive PCI continued to manage their heart disease with medication.
The study met its primary endpoint—a composite of death from any cause, myocardial infarction (MI) or revascularisation after two years of follow-up. Compared with patients who were evaluated by IVUS, significantly fewer patients evaluated by FFR underwent PCI (65.3% vs. 44.4%, respectively). After two years, 8.1% of the patients evaluated by FFR had died, had an MI or needed a repeat stenting procedure, compared with 8.5% of those evaluated by IVUS, a non-statistically significant difference. In addition, when the investigators compared patients who received PCI with those who remained on medical therapy, they found no statistically significant differences in the rates of death, heart attacks or repeat procedures in either the FFR or IVUS group.
“Despite the fact that FFR-evaluated patients received significantly fewer stents than IVUS-evaluated patients, they were no more likely to experience adverse events,” Koo said. “The rates of adverse outcomes and patients’ quality of life were similar in both groups. These results support considering FFR-guided PCI first for patients with intermediate coronary stenosis, as it is associated with a reduced use of medical resources.”
The study has some limitations, Koo said. Its findings apply only to patients with intermediate coronary stenosis and not those with more severe blockages of the coronary artery. Also, the study examined only FFR guidance compared with IVUS guidance. Additional studies are needed to comparatively evaluate other technologies for evaluating patients’ need for PCI. The study was funded by a grant from Boston Scientific.
