Thrombocytosis-associated ticagrelor non-responder status after ECMO-supported primary PCI in STEMI

Despite established treatment pathways for ST-elevation myocardial infarction (STEMI), complications range from adverse events such as malignant cardiac arrhythmias to more elusive risks such as thrombocytosis compromising antiplatelet efficacy. We describe a case of ticagrelor non-responsiveness in a patient who developed critical reactive thrombocytosis after veno-arterial extracorporeal membrane oxygenation-supported percutaneous coronary intervention for inferior STEMI. High on-treatment platelet reactivity was detected by Multiplate (Roche Diagnostics, Mannheim, Germany) testing at a time when the platelet count exceeded 1.1 × 10⁶/μl. Given the absence of alternative platelet function platforms at the treatment center, prasugrel was introduced based on the available test results, with subsequent normalization of platelet function. Unlike clopidogrel and prasugrel, resistance to ticagrelor has rarely been reported. This case highlights the need for individualized antiplatelet strategies in high-risk profiles.

Ticagrelor may present a pharmacodynamic challenge in patients with thrombocytosis. In very high-risk patients, particularly those with atypical hematologic profiles, verifying the efficacy of platelet aggregation inhibition through laboratory testing is essential.