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Acute posterior ST-elevation myocardial infarction in a patient taking an oral anticoagulant — MRCEM SBA MCQ

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HardCardiovascular emergenciesAcute posterior ST-elevation myocardial infarction in a patient taking an oral anticoagulantMRCEM SBA

A 62-year-old man presents to a district general hospital 80 minutes after the onset of persistent central chest pain. He takes apixaban for atrial fibrillation and has no active bleeding or aspirin allergy. His blood pressure is 128/76 mmHg. The 12-lead ECG shows 2 mm horizontal ST depression and tall R waves in V1–V3, without ST elevation in the standard leads. An ECG with posterior leads shows 1 mm ST elevation in V7–V9. Monitoring and intravenous access are established. The regional cardiac centre can deliver primary PCI 75 minutes after fibrinolysis could be started locally. Which initial treatment and disposition plan is most appropriate?

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

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Correct answer: E — Give aspirin and clopidogrel, and transfer immediately for primary PCI.

The anterior ST depression and tall R waves raise suspicion of posterior infarction; ST elevation in V7–V9 confirms a posterior ST-elevation pattern. The absence of ST elevation in the standard leads must not divert this patient into an NSTEMI pathway. He presents within 12 hours, and primary PCI is available within 120 minutes of when fibrinolysis could be given, so immediate transfer for primary PCI is preferred. Give aspirin 300 mg unless contraindicated. Because he already takes an oral anticoagulant, NICE recommends clopidogrel, rather than prasugrel, as the additional antiplatelet agent for STEMI treated with primary PCI. A selects fibrinolysis despite timely access to primary PCI. B selects the usual preferred additional antiplatelet agent for a patient having primary PCI who is *not* already taking an oral anticoagulant. C also reaches the right reperfusion pathway, but ticagrelor is not the recommended additional agent in this anticoagulated patient. D selects appropriate drugs but delays reperfusion by treating a posterior STEMI as NSTEMI. The receiving cardiac team should direct procedural anticoagulation and subsequent antithrombotic treatment.

Reference: Primary Percutaneous Coronary Intervention Protocol (Revised 2019) — https://www.england.nhs.uk/wp-content/uploads/sites/5/2019/04/PPCI-protocol-revised-2019-NDP.pdf Acute coronary syndromes: recommendations 1.1.4, 1.1.6 and 1.1.19 (18 November 2020) — https://www.nice.org.uk/guidance/NG185/chapter/recommendations Acute coronary syndromes: recommendation 1.1.11 (18 November 2020) — https://www.nice.org.uk/guidance/NG185/chapter/recommendations