Massive Anterior STEMI Due to Essential Thrombocythemia Leading to Urgent Thrombocytapheresis

Myocardial infarction in essential thrombocythemia (ET) is a rare but severe complication of this myeloproliferative disorder, occurring in approximately 2% to 3% of the population.

A 78-year-old man with calreticulin-mutated ET presented with massive anterior ST-segment elevation myocardial infarction (STEMI). Urgent coronary angiogram revealed subtotal left anterior descending artery stenosis due to heavy thrombus burden, leading to partial revascularization. His platelet count exceeded 1,200 × 10⁹/L on admission, justifying prompt thrombocytapheresis in the coronary care unit.

In acute symptomatic thrombohemorrhagic complications, the American Society for Apheresis designates thrombocytapheresis as a Class II recommendation. This case describes the novel use of thrombocytapheresis in the setting of anterior STEMI with ET.

STEMI complicating acutely decompensated ET is life threatening, and early thrombocytapheresis should be considered in select patients. This case demonstrates the potential benefit of more aggressive cytoreductive therapy in patients with ET and underlying cardiovascular risk factors.