In PCI, FFR guidance noninferior to IVUS guidance for clinical outcomes at 2 years: FLAVOUR
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WASHINGTON — In a head-to-head trial, PCI guided by fractional flow reserve was noninferior to PCI guided by IVUS for death, MI and revascularization at 2 years, researchers reported at the American College of Cardiology Scientific Session.
“There have been no head-to-head, outcome-based clinical trials that compare imaging vs. physiology guidance in patients with intermediate stenosis,” Bon-Kwon Koo, MD, interventional cardiologist at Seoul National University Hospital in South Korea, said during a press conference. “The FLAVOUR trial was designed to compare the efficacy of FFR- vs. IVUS-guided PCI. We hypothesized that for 2-year outcomes, FFR would be noninferior to the IVUS-guided strategy.”
In the FLAVOUR trial of 1,682 patients with CAD with intermediate stenosis (mean age, 65.1 years; 70.6% men), the FFR group showed noninferiority in the primary outcome of all-cause mortality, MI or any revascularization at 2 years (FFR, 8.1%; IVUS, 8.5%; risk difference, –0.4 percentage points; P for noninferiority = .015), Koo said.
There were also no differences between the groups in all-cause death, cardiac death, noncardiac death, MI, periprocedural MI, spontaneous MI, target vessel MI, revascularization, ischemia-driven revascularization, target vessel revascularization and stroke (P > .05 for all), he said.
In the FFR group, a patient was indicated for PCI if FFR was less than 0.8, and in the IVUS group, PCI was indicated if the minimum lumen area was 3 mm2 or less or if minimum lumen area was 3 mm2 to 4 mm2 and plaque burden was greater than 70%, Koo said. PCI was performed in 33% of the FFR group and 58% of the IVUS group.
In the FFR group, the primary outcome occurred more often in those who had PCI compared with those who had medical therapy (P = .001), but that was not the case in the IVUS group (P = .212), Koo said.
The per-protocol analysis of the primary outcome was similar to the intention-to-treat outcome, and the primary outcome was consistent by prespecified subgroups, he said.There was also no difference between the groups in Seattle Angina Questionnaire scores related to physical limitation, angina stability, anginal frequency, treatment satisfaction and quality of life, according to the researchers.
All patients were eligible for PCI and had a target vessel size of more than 2.5 mm. All were suspected to have ischemic heart disease and had intermediate coronary stenosis on angiography.
The researchers determined that optimal PCI was achieved in the FFR group if FFR was at least 0.88 after the procedure or delta FFR across the stent < 0.05 and in the IVUS group if plaque burden at the edge of the stent was 55% or less, the minimal stent area was at least 5.5 mm2 or the minimal stent area was greater than or equal to the distal reference lumen area. Optimal PCI was achieved in 50.1% of the FFR group and 54.8% in the IVUS group.
“In patients with intermediate stenosis, FFR-guided PCI was noninferior to IVUS-guided PCI in respect to the primary composite outcome at 2 years after the procedure,” Koo said at the press conference. “FFR guidance was associated with a lower rate of stent implantation, but there was no difference in patient-reported outcomes between the two strategies.”
Editor’s Note: This article was modified on April 13, 2022 with updates to the data.
Perspective
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B. Hadley Wilson, MD, FACC
For over a decade, we have known we can have better outcomes in PCI if guided by physiology via FFR. The FLAVOUR trial was looking to see if there were comparable results with using IVUS-guided PCI. After 2 years, major adverse CV effects were comparable, suggesting that FFR and IVUS are both good technologies to guide successful PCI, with low major adverse events over time.
The one caveat is that FFR-guided PCI had a lower rate of stent implantation than with IVUS, despite there being no difference in major outcomes.
When there is concern for the complexity of a coronary lesion, one can be guided by FFR or IVUS. FFR is used more often in the U.S. than IVUS, so IVUS is likely to be used in the minority of cases where the proceduralist wants to characterize the complexity of the lesion better than can be done with FFR alone.
Perspective
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Roxana Mehran, MD
Use of FFR guidance or IVUS guidance for PCI is extremely important, and we are underutilizing them. Which one is best? The researchers found no differences in outcomes between IVUS guidance and FFR guidance, but in the FFR group, there were many fewer patients who required stenting. When they deferred the intervention, those patients did extremely well. Overall, the FFR guidance was fantastic in deferring patients safely, and was associated with fewer procedures and similar outcomes. It is a win for FFR. Physiology matters.
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Koo BK, et al. Late-Breaking Clinical Trials V. Presented at: American College of Cardiology Scientific Session; April 2-4, 2022; Washington, D.C. (hybrid meeting).
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