Instantaneous Wave-Free Ratio (IFR) is a highly precise, vasodilator-free physiological index used to assess the hemodynamic significance of coronary stenosis. This session provides a comprehensive, clinician-focused review of IFR concepts, acquisition techniques, interpretation criteria, and integration into revascularization decision-making. As many interventionalists refine their physiologic assessment skills through cardiology conference, this session mirrors that depth by unpacking the science and application of advanced IFR assessment strategies that guide safe, evidence-based PCI planning.

The session begins with the physiologic foundation of IFR, explaining how the wave-free period in diastole represents a phase of minimized microvascular resistance, allowing reliable pressure-derived assessment without adenosine. Participants will understand the difference between IFR and FFR, how coronary microcirculation behaves in resting and hyperemic conditions, and why IFR offers strong clinical equivalence while improving workflow efficiency and patient tolerance.

Attendees will learn how to acquire accurate IFR measurements using pressure wires and modern consoles. The description covers equalization steps, pullback maneuvers, drift detection, and interpretation of step-up changes along the vessel. Case examples illustrate typical IFR thresholds, borderline values, lesion-level heterogeneity, and the impact of diffuse versus focal disease.

The session also explores hybrid strategies combining IFR and FFR in cases of borderline readings or microvascular dysfunction. Participants will learn how to differentiate true ischemia from pseudo-significant lesions influenced by vessel size, vasoconstriction, or measurement artifact. The role of IFR in left-main assessment, serial lesions, bifurcation disease, and CTO planning is presented with practical algorithms.

An important component of the session focuses on integrating IFR into revascularization decisions. Participants will review clinical trial data supporting IFR-guided PCI, understanding how physiology-driven therapy reduces unnecessary stenting, improves outcomes, and decreases procedure time. Special clinical scenarios—including microvascular angina, slow-flow conditions, post-PCI optimization, and post-CABG graft assessment—are discussed to show how IFR can be applied across diverse patient groups.

Workflow optimization is also highlighted, including catheter-lab efficiency, reduced patient discomfort, improved cost effectiveness, and enhanced operator confidence. Future perspectives include AI-assisted physiologic mapping, pressure-wire-free computation derived from angiography, and fully automated IFR pullback analysis that predicts optimal stent locations.

Real-world case vignettes illustrate how IFR correlates with symptoms, imaging, and long-term functional outcomes. Participants will receive structured interpretation templates and sample reports that can be integrated into daily practice, ensuring that physiologic decision-making remains consistent and reproducible.