Key Points:
- In the FLAVOUR II trial, 1839 patients with angiographically-significant coronary artery disease were randomized to receive angiography-derived fractional flow reserve (AngioFFR) guided vs. intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI).
- Fewer patients in the AngioFFR-guided group underwent PCI compared to the IVUS-guided group (73.9% vs. 83.1%; p<0.001).
- AngioFFR-guided PCI was found to be non-inferior to IVUS-guided PCI for the primary outcome, a composite of death, myocardial infarction or revascularization at 12 months.
Although use of intravascular ultrasound (IVUS) and use of angiography-derived fractional flow reserve (AngioFFR) have both been shown to improve outcomes compared to angiography-guided percutaneous coronary intervention (PCI) alone, it is unclear whether there are differences in outcomes between use of IVUS vs. AngioFFR. In the FLAVOUR II trial, the authors randomized patients with angiographically significant coronary disease to AngioFFR-guided vs. IVUS-guided PCI and evaluated a composite outcome of death, myocardial infarction (MI) or revascularization at 12 months. In the AngioFFR group, an AI-powered method of fractional flow reserve assessment was used to estimate fractional flow reserve from a single-view angiogram and patients underwent PCI if the AngioFFR was 0.80 or less. In the IVUS group, the criteria for PCI was a minimal lumen area ≤ 3.0 mm2 or 3.0 mm2 to 4.0 mm2 with a plaque burden > 70%.
A total of 1839 patients (68% men) with an average age of 66 years old across 22 medical centers in China were randomized. There were high rates of comorbidities associated with coronary artery disease including 67.6% hypertension, 31% diabetes, 66.9% hyperlipidemia, 24.3% chronic kidney disease, 25.9% current smokers, and 13.9% with a prior MI. Based on the AngioFFR and IVUS criteria for PCI, fewer patients in the AngioFFR group underwent PCI compared to the IVUS group (73.9% vs. 83.1%; p<0.001). At 12 months, the rate of the primary outcome was found to be non-inferior in the AngioFFR-guided arm compared to the IVUS-guided arm (6.3% vs. 6.0%; p=0.022 for noninferiority). There was also no difference in the primary outcome whether the patient underwent medical treatment or PCI. One important limitation of the study is that the patients had relatively low anatomical complexity with a median SYNTAX score of 9. This is especially important because it is unclear whether the performance of the non-invasive AngioFFR strategy would be the same in more complex coronary lesions. In conclusion, the FLAVOUR II trial provides important evidence supporting the use of AngioFFR, a fast and minimally-invasive strategy for coronary lesion evaluation, as an alternative to IVUS to guide PCI.