Abstract
BACKGROUND: Essential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm characterised by clonal thrombocytosis and an overall increased risk of thrombotic events. Acute coronary syndrome as an initial presentation of ET is rare in the literature. CASE SUMMARY: A 39 year old woman with established ET presented with non-ST-elevation myocardial infarction (NSTEMI). Coronary angiography revealed a hazy, eccentric mid-right coronary artery lesion. Optical coherence tomography (OCT) demonstrated thrombus without atherosclerotic plaque. OCT-guided direct stenting achieved optimal expansion with thrombolysis in myocardial infarction (TIMI) Grade III flow. She was discharged on dual antiplatelet therapy and referred to haematology for ET management. At three months, she remained asymptomatic on clinic follow-up. CONCLUSION: OCT provided diagnostic and procedural guidance in a rare thrombotic NSTEMI secondary to ET. This case highlights the role of intracoronary imaging in differentiating thrombosis from atherosclerotic plaque rupture.