Clinical Relevance of Discordance Between Physiology- and Imaging-Guided PCI Strategies in Intermediate Coronary Stenosis

Abstract

Background: Recent randomized clinical trials have demonstrated the benefits of intravascular imaging (IVI)-guided percutaneous coronary intervention (PCI) over angiography-guided PCI. However, the role of angiography-based physiological assessment during IVI-guided PCI remains unclear. Objectives: This study aimed to explore the discrepancies and significance of angiography-based physiological assessments in IVI-guided PCI. Methods: In the international multicenter randomized FLAVOUR (Fractional Flow Reserve and Intravascular Ultrasound for Clinical Outcomes in Patients With Intermediate Stenosis) trial, angiography-based physiological assessment was retrospectively performed using the Murray law–based quantitative flow ratio (μQFR). In this post hoc analysis, patients were categorized based on intravascular ultrasound (IVUS)-guided treatment decisions (PCI or deferral) and μQFR as follows: negative μQFR with deferral of PCI (DEFER), negative μQFR with PCI (PERFORM), and positive μQFR with PCI (REFERENCE). The primary outcome was major adverse cardiovascular events, defined as a composite of death, myocardial infarction, and target vessel revascularization at the 24-month follow-up. Results: Of the 784 patients, 34.4% (270/784), 29.3% (230/784), and 31.5% (247/784) were categorized into the DEFER, PERFORM, and REFERENCE groups, respectively. Physiological assessment led to substantial reclassification, encompassing 48.2% (230/477) of patients who underwent IVUS-guided PCI. The REFERENCE group showed a higher risk for major adverse cardiovascular events at 2 years compared with the PERFORM group (adjusted HR: 2.46; 95% CI: 1.13-5.35; P = 0.023). However, the primary outcomes in the DEFER and PERFORM groups were similar (adjusted HR: 0.88; 95% CI: 0.37-2.11; P = 0.779). The quality of life at 2 years was comparable among the 3 groups (P = 0.198). Conclusions: Angiography-based physiological assessments can offer additional prognostic insights for patients undergoing IVI-guided PCI. IVUS-guided PCI may not be advantageous in patients with functionally insignificant lesions.