In patients with coronary artery disease who are being evaluated for percutaneous coronary intervention (PCI), procedures may be guided by fractional flow reserve (FFR) or intravascular ultrasound (IVUS) for decision making regarding revascularization and stent implantation. However, the differences in clinical outcomes when a single method is used for both purposes are unclear.
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We randomly assigned 1682 patients being evaluated for PCI for the treatment of intermediate stenosis (40-70% occlusion by visual assessment on coronary angiography) in a 1:1 ratio to undergo a procedure guided by FFR or by IVUS. FFR or IVUS should be used to determine if PCI should be performed and to assess the success of PCI. In the FFR group, PCI had to be performed if the FFR was 0.80 or less. In the IVUS group, criteria for PCI were an area of minimal light measuring either 3 mm2 or less or measuring 3 to 4 mm2 with a plate load of more than 70%. The primary endpoint was a composite endpoint of death, myocardial infarction, or revascularization at 24 months after randomization. We tested the non-inferiority of the FFR group compared to the IVUS group (margin of non-inferiority, 2.5 percentage points).
The frequency of PCI was 44.4% in patients in the FFR group and 65.3% in those in the IVUS group. At 24 months, a primary outcome event had occurred in 8.1% of patients in the FFR group and 8.5% of those in the IVUS group (absolute difference, -0.4 percentage points; upper limit of one-sided 97.5% confidence interval, 2.2 percentage points; P = 0.01 for non-inferiority). Patient-reported outcomes, as reported on the Seattle Angina Questionnaire, were similar in the two groups.
In patients with intermediate stenosis who were being evaluated for PCI, FFR guidance was non-inferior to IVUS guidance for the composite primary outcome of death, myocardial infarction, or revascularization at 24 months. (Funded by Boston Scientific; FLAVOR ClinicalTrials.gov number, NCT02673424.)