Fractional flow reserve guided percutaneous coronary intervention optimization directed by high-definition intravascular ultrasound versus standard of care: Rationale and study design of the prospective randomized FFR-REACT trial.

BACKGROUND: Post percutaneous coronary intervention (PCI) fractional flow reserve (FFR) is a significant predictor of major adverse cardiac events (MACE). The rationale for low post procedural FFR values often remains elusive based on angiographic findings alone, warranting further assessment using an FFR pullback or additional intravascular imaging. It is currently unknown if additional interventions intended to improve the PCI, decrease MACE rates. STUDY DESIGN: The FFR REACT trial is a prospective, single-center randomized controlled trial in which 290 patients with a post PCI FFR <0.90 will be randomized (1:1) to either standard of care (no additional intervention) or intravascular ultrasound (IVUS)-directed optimization of the FFR (treatment arm). Eligible patients are those treated with angiographically successful PCI for (un)stable angina or non-ST elevation myocardial infarction (MI). Assuming 45% of patients will have a post PCI FFR <0.90, approximately 640 patients undergoing PCI will need to be enrolled. Patients with a post PCI FFR ≥ 0.90 will be enrolled in a prospective registry. The primary end point is defined as a composite of cardiac death, target vessel MI and clinically driven target vessel revascularisation (target vessel failure) at 1 year. Secondary end points will consist of individual components of the primary end point, procedural success, stent thrombosis and correlations on clinical outcome, changes in post PCI Pd/Pa and FFR and IVUS derived dimensions. All patients will be followed for 3 years. CONCLUSION: The FFR-REACT trial is designed to explore the potential benefit of HD-IVUS-guided PCI optimization in patients with a post PCI FFR <0.90 (Dutch trial register: NTR6711).

Explanation of Postprocedural Fractional Flow Reserve Below 0.85.

BACKGROUND: Fractional flow reserve (FFR) after percutaneous coronary intervention is a predictor of adverse cardiovascular events during follow-up. However, the rationale for low post procedural FFR values remains often elusive based on angiographic findings alone. METHODS AND RESULTS: FFR SEARCH (Stent Evaluated at Rotterdam Cardiology Hospital) is a prospective single-center registry in which post-percutaneous coronary intervention FFR was assessed in 1000 consecutive all-comer patients. FFR measurements were performed with a microcatheter ±20 mm distal to the most distal stent edge. In 100 vessels with a post procedural FFR ≤0.85, and 20 vessels >0.85 high definition intravascular ultrasound analysis was performed. In 100 vessels with a post-percutaneous coronary intervention FFR ≤0.85, mean post procedural FFR was 0.79±0.05. Minimal lumen area was 2.19 (1.81-3.19) mm2, mean lumen area was 5.95 (5.01-7.03) mm2, and minimal stent area was 4.01 (3.09-5.21) mm2. Significant residual focal proximal lesions were found in 29% of the assessed vessels whereas, focal distal lesions were found in 30% of the vessels. Stent underexpansion and malapposition were found in 74% and 22% of vessels, respectively. Clear focal signs of luminal narrowing were found in 54% of the vessels analyzed. Although incidences of focal lesions, underexpansion, and malapposition were similar between both cohorts, minimal stent area was significantly smaller in vessels with a post-percutaneous coronary intervention FFR ≤0.85 as compared with those with an FFR >0.85. CONCLUSIONS: In patients with a post procedural FFR ≤0.85, intravascular ultrasound revealed focal signs of luminal narrowing in a significant number of cases.