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Left Main Stem Disease — EECC MCQ

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ModerateCoronary Artery DiseaseLeft Main Stem DiseaseEECC

A 50-year-old woman undergoes emergency coronary angiography for STEMI. Angiography shows a thrombus-laden culprit lesion in the mid-LAD but also reveals an 80% ostial left main stem stenosis. She is haemodynamically stable. PCI is performed to the LAD with good result. What should be discussed regarding the left main stenosis?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: C — Refer for urgent CABG within the index admission

Explanation lettering: E = shown as A · C = shown as B · B = shown as C · A = shown as D · D = shown as E

An ostial left main stem stenosis of 80% is haemodynamically significant and carries high prognostic risk. CABG is recommended for left main stem disease, particularly when the SYNTAX score is likely intermediate-high. In the acute STEMI setting, the culprit lesion is treated first with PCI, and the left main disease should be discussed by the Heart Team with urgent CABG arranged. Ad-hoc PCI to the left main (A) during an acute STEMI is not recommended unless cardiogenic shock dictates otherwise. FFR deferral (C) is inappropriate for an 80% ostial LMS. Medical therapy alone (D) is not adequate. While IVUS (E) may be useful for intermediate lesions, an 80% ostial stenosis is clearly significant.

Reference: ESC (2023): Guidelines for the Management of Acute Coronary Syndromes