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IVUS for Left Main Assessment — EECC MCQ

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ModerateCoronary Artery DiseaseIVUS for Left Main AssessmentEECC

A 65-year-old man with left main coronary artery disease (50% stenosis) is assessed. The Heart Team discusses whether IVUS should be used to guide the decision. What role does IVUS play in left main assessment?

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Correct answer: E — IVUS is recommended for left main lesion assessment — a minimum lumen area (MLA) ≤6 mm² by IVUS correlates with haemodynamic significance and supports revascularisation; IVUS provides more accurate LMS sizing than angiography which is limited by vessel overlap and foreshortening

The left main coronary artery is notoriously difficult to assess by angiography alone due to: (1) vessel overlap (bifurcation with LAD/LCx); (2) foreshortening; (3) catheter dampening obscuring ostial disease; (4) eccentric plaque underestimated by 2D angiography. IVUS provides cross-sectional imaging with accurate measurement of: MLA (minimum lumen area — ≤6 mm² correlates with FFR ≤0.80 and predicts adverse outcomes), plaque burden, and reference vessel dimensions. The 2024 ESC CCS Guidelines recommend IVUS (or OCT) for ambiguous LMS lesions (Class IIa). For LMS PCI, intravascular imaging-guided optimisation is recommended (Class I for complex PCI) to ensure adequate stent expansion and apposition — the MAIN-COMPARE registry showed IVUS-guided LMS PCI had better outcomes than angiography-guided.

Reference: ESC (2024): CCS Guidelines