Comparison of Fractional FLow Reserve And Intravascular ultrasound-guided Intervention Strategy for Clinical OUtcomes in Patients with InteRmediate Stenosis (FLAVOUR): Rationale and design of a randomized clinical trial.

BACKGROUND: Coronary angiography has limitations in defining the ischemia-causing stenotic lesion, especially in cases with intermediate coronary stenosis. Fractional flow reserve (FFR) is a current standard method to define the presence of ischemia, and intravascular ultrasound (IVUS) is the most commonly used invasive imaging tool that can provide the lesion geometry and can provide the information on plaque vulnerability. The primary aim of this study is to compare the safety and efficacy of FFR-guided and IVUS-guided percutaneous coronary intervention (PCI) strategies in patients with intermediate coronary stenosis.

TRIAL DESIGN: Comparison of Fractional FLow Reserve And Intravascular ultrasound-guided Intervention Strategy for Clinical OUtcomes in Patients with InteRmediate Stenosis (FLAVOUR) trial is an international, multicenter, prospective, randomized clinical trial. A total of 1,700 consecutive patients with intermediate stenosis (40%-70% by visual estimation) in a major epicardial coronary artery will be randomized 1:1 to receive either FFR-guided or IVUS-guided PCI strategy. Patients will be treated with PCI according to the predefined criteria for revascularization; FFR ≤ 0.80 in the FFR-guided group and Minimal Lumen Area (MLA) ≤3 mm2 (or 3 mm2 <MLA ≤4 mm2 and plaque burden >70%) in the IVUS-guided group. The primary end point is the patient-oriented composite outcome, which is a composite of all-cause death, myocardial infarction, and any repeat revascularization at 24months after randomization. We will test noninferiority of current standard FFR-guided PCI strategy compared with IVUS-guided decision for PCI and stent optimization strategy.

CONCLUSION: The FLAVOUR trial will compare the safety and efficacy of FFR- and IVUS-guided PCI strategies in patients with intermediate coronary stenosis. This study will provide an insight on optimal evaluation and treatment strategy for patients with intermediate coronary stenosis.