Webinar 10 | Assessment of Left Main Stenosis-Slides: Physiologic Assessment of LM, Dr. Bon-Kwon Koo

Slides: Physiologic Assessment of LM, Dr. Bon-Kwon Koo

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This presentation by Dr. Bon-Kwon Koo from Seoul National University Hospital discusses the physiologic assessment of left main (LM) coronary artery stenosis and the role of physiology-guided percutaneous coronary intervention (PCI). Traditional angiography often falls short in accurately determining LM lesion significance. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) have emerged as key invasive physiologic indexes that provide reliable functional evaluation of LM lesions and can guide treatment decisions more safely and effectively.<br /><br />Studies have shown moderate correlation between angiographic and physiologic assessments, emphasizing the value of physiology-based diagnosis. The SYNTAX score is enhanced conceptually by a functional SYNTAX score that counts only physiologically significant lesions, improving risk stratification. Safety and outcomes data support physiology-guided decision making in LM stenosis, including better prediction of side branch significance after stenting, and long-term favorable outcomes with physiology-guided complete revascularization.<br /><br />Potential pitfalls in FFR measurement, such as inadequate hyperemia, drift, guiding catheter damping, and microvascular dysfunction, require careful attention to avoid misinterpretation. The presentation highlights the importance of experience in applying physiologic indices, especially for complex scenarios such as bifurcation lesions and jailed side branches.<br /><br />Recent data on angiography-derived FFR (QFR) show promise but with only moderate correlation and classification agreement compared to pressure-wire FFR. Post-stent FFR values provide prognostic information, with lower post-PCI FFR linked to increased risk of target vessel failure and cardiac events.<br /><br />A physiology-guided algorithm developed by Korean, Japanese, and European Bifurcation Clubs is proposed for LM lesions. Overall, the message is that physiology-guided PCI for LM disease is feasible throughout the procedural course and can reduce unnecessary interventions and complications. However, successful implementation requires thorough understanding of coronary physiology and recognition of index limitations. The adoption of guideline-supported physiology assessment, rather than debate over different indices, is emphasized for improving LM revascularization outcomes.

Keywords

Left main coronary artery stenosis

Physiology-guided PCI

Fractional flow reserve (FFR)

Instantaneous wave-free ratio (iFR)

Angiographic assessment

Functional SYNTAX score

Physiology-based diagnosis

Bifurcation lesions

Angiography-derived FFR (QFR)

Post-stent FFR prognostic value