Dynamic Flap at the Coronary Opening Mimicking Left Main Disease

BACKGROUND: Coronary ostial valve-like ridges are rare anatomical variants that dynamically obstruct coronary inflow, mimicking left main coronary artery disease. CASE SUMMARY: A 39-year-old man presented with acute coronary syndrome, global left ventricular systolic dysfunction, and ST-segment elevation in lead aVR on 12-lead electrocardiogram. Coronary angiography revealed no fixed coronary stenosis but a mobile, valve-like flap at the left coronary ostium. Myocardial ischemia worsened during intra-aortic balloon pump support and was promptly and markedly relieved after stent deployment covering the left main coronary artery ostium. Despite initial recovery, he died on day 6 from a refractory ventricular tachycardia storm. Autopsy revealed diffuse subendocardial infarction and a 4-mm ridge-like protrusion from the sinotubular junction, consistent with a coronary ostial valve-like ridge. DISCUSSION: Diastolic compression of an ostial ridge can cause dynamic coronary obstruction and critical ischemia, even with moderate atherosclerosis. TAKE-HOME MESSAGE: Early recognition of an ostial valve-like ridge prevents dynamic obstruction and death.