Strategic Comparison Of Ischemia-based Versus Plaque Burden and vulnErability-based Revascularization in High-Risk Coronary Artery Disease Patients

1. Study Purpose This study aims to compare clinical outcomes between two revascularization strategies in patients with high-risk coronary artery disease and 50-90% angiographic stenosis: a plaque burden and vulnerability-based revascularization strategy guided by intravascular imaging versus an ischemia-based revascularization strategy guided by physiologic assessment. 2. Background Percutaneous coronary intervention (PCI), in conjunction with optimal medical therapy, is one of the main therapeutic strategies for improving outcomes in patients with CAD. To enhance the results of PCI, various diagnostic and adjunctive techniques have been developed-most notably, invasive physiologic assessment and intravascular imaging (IVI). Invasive physiologic indices such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are recognized as the most accurate methods to determine vessel-level myocardial ischemia, and current guidelines recommend PCI based on these physiological measurements. Recently, angiography-derived FFR has also been developed, allowing ischemia assessment without pressure wire measurement, and has been endorsed as a useful tool for guiding PCI decisions. Intravascular imaging, on the other hand, provides detailed anatomical insights into atherosclerotic plaque morphology and plays a critical role in achieving procedural optimization. Current guidelines recommend the use of IVI, particularly in the treatment of complex lesions. While most previous IVI studies have focused on procedural optimization, more recent investigations have begun to explore the use of IVI for PCI decision-making itself. Emerging data suggest that revascularization decisions based on quantitative and qualitative plaque assessment using IVI are non-inferior to those based on invasive physiologic testing. Moreover, IVI enables the identification of vulnerable plaques, and studies indicate that intervening on such lesions may improve outcomes. At present, a physiology-guided decision-making strategy combined with IVI-guided optimization is considered the best evidence-based approach according to guidelines. However, recent data showing the potential advantages of IVI-guided decision-making and IVI-guided optimization-particularly in high-risk, complex patients and in those with vulnerable plaque morphology-suggest that IVI-based strategies may offer greater clinical benefit in such populations. Despite this, a comprehensive strategy that integrates both quantitative (plaque burden) and qualitative (vulnerability) aspects of plaque evaluation via IVI has yet to be clearly established. Therefore, this study seeks to propose IVI-based quantitative and qualitative criteria for high-risk CAD patients and to compare outcomes between a plaque burden and vulnerability-based revascularization strategy and the conventional ischemia-based revascularization strategy. For all patients undergoing PCI, IVI-guided optimization will be performed to ensure the highest possible procedural quality in both groups. 3. Study Procedures Patients undergoing coronary angiography for suspected or known CAD will be screened for eligibility. After providing a detailed explanation of the study, written informed consent will be obtained from those deemed appropriate for participation. Following coronary angiography, patients with significant coronary stenosis who meet all inclusion and no exclusion criteria will be enrolled in the study. Eligible participants will then be randomized in a 1:1 ratio to either the plaque burden and vulnerability-based revascularization group or the ischemia-based revascularization group. Stratified randomization will be performed according to participating center and presence or absence of acute coronary syndrome (ACS) to ensure balance between the groups.