Reperfusion Strategy in STEMI
A 62-year-old woman with diabetes, hypertension, and an ischaemic stroke one month ago has three hours of central chest pain. She takes aspirin, lisinopril, and metoprolol. Pain persists after oxygen, morphine, and sublingual nitroglycerin. Blood pressure is 142/86 mm Hg, and ECG shows 3 mm ST elevation in leads V2 to V5. A catheterisation laboratory is available on site. Which of the following is the most appropriate next step?
- A.Intravenous magnesium sulfate
- B.CT angiography of the aorta
- C.Intravenous thrombolytic therapy
- D.Urgent coronary angiographyCorrect
Explanation
Anterior ST elevation with ongoing ischaemic chest pain in a high-risk diabetic patient is an ST-elevation myocardial infarction requiring immediate reperfusion. Primary percutaneous coronary intervention is the preferred strategy whenever it can be achieved within 120 minutes of first medical contact, and it is superior to fibrinolysis in mortality, reinfarction, and stroke; with an on-site catheterisation laboratory the target door-to-balloon time is under 60 to 90 minutes. Fibrinolysis is a fallback only where timely intervention is unavailable, and it is absolutely contraindicated here because ischaemic stroke within the preceding three months carries an unacceptable risk of intracranial haemorrhage. Other absolute contraindications include any prior intracerebral haemorrhage, known cerebral vascular malformation or malignant intracranial neoplasm, suspected aortic dissection, active bleeding, and significant closed head injury within three months. Ongoing pain despite nitrates and morphine confirms persistent ischaemia and reinforces urgency. Magnesium is used for torsades de pointes or documented hypomagnesaemia and has no role in routine infarct care. CT aortography would be appropriate if dissection were suspected, which requires tearing pain radiating to the back, a pulse or blood pressure differential, or a widened mediastinum, none of which are described. Dual antiplatelet therapy and anticoagulation should be given while activating the catheterisation laboratory.
Why each option
- A.
- Magnesium is indicated for torsades de pointes or hypomagnesaemia and confers no benefit in acute infarction.
- B.
- CT aortography is for suspected dissection, which is not suggested by this presentation with clear regional ST elevation.
- C.
- Fibrinolysis is contraindicated by ischaemic stroke within the past three months and is inferior to percutaneous intervention when a laboratory is on site.
- D.
- Correct. Urgent coronary angiography with primary percutaneous intervention is the preferred reperfusion strategy when it can be delivered promptly.
Reference: ESC Guidelines for the Management of Acute Coronary Syndromes, 2023
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