What is the management of a ST-Elevation Myocardial Infarction (STEMI)?

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for STEMI patients when it can be performed within 90 minutes of first medical contact, with fibrinolytic therapy indicated when anticipated time to PCI exceeds 120 minutes. 1

Initial Management

• Obtain 12-lead ECG within 10 minutes of first medical contact
• Establish continuous ECG monitoring with defibrillator capacity immediately
• Administer immediate pharmacological therapy:
  • Aspirin 162-325 mg (non-enteric coated, chewed) 1
  • Loading dose of P2Y12 inhibitor: ticagrelor 180 mg or prasugrel 60 mg (preferred), or clopidogrel 600 mg as alternative 1
    • Note: Prasugrel is contraindicated in patients with history of TIA/stroke or active bleeding 2
    • Avoid prasugrel in patients ≥75 years old except in high-risk situations (diabetes or prior MI) 2
  • Anticoagulation: unfractionated heparin, enoxaparin, or bivalirudin (fondaparinux contraindicated for primary PCI) 1
  • Beta-blockers in patients without contraindications 1

Reperfusion Strategy Decision Algorithm

1. Primary PCI available within 90 minutes of first medical contact?

   • Yes → Transfer for immediate primary PCI
   • No → Proceed to step 2

2. Time from symptom onset < 12 hours and anticipated time to PCI > 120 minutes?

   • Yes → Administer fibrinolytic therapy followed by immediate transfer to PCI-capable center
   • No → Transfer for primary PCI regardless of time delays 1

3. For patients 12-48 hours after symptom onset:

   • Do not administer fibrinolysis
   • Consider urgent catheterization and revascularization 1

Post-Reperfusion Management

• Monitor all patients for at least 24 hours after reperfusion therapy 1
• Start ACE inhibitors within 24 hours in patients with:
  • Anterior STEMI
  • Heart failure
  • LVEF <40% 1
• Continue dual antiplatelet therapy (DAPT):
  • For at least 12 months after PCI 1
  • Prasugrel 10 mg daily (consider 5 mg daily in patients <60 kg) 2
  • Premature discontinuation increases risk of stent thrombosis 1

Special Considerations

• Cardiogenic shock: Implement immediate reperfusion-based strategy using primary PCI 1
• Right ventricular failure: Presents with hypotension, clear lung fields, and elevated jugular venous pressure 1
• Ventricular septal rupture: Diagnose with new systolic murmur, echocardiography with color Doppler; urgent surgical repair indicated 1
• CABG considerations: When possible, discontinue prasugrel at least 7 days prior to surgery 2

Secondary Prevention

• Dual antiplatelet therapy for at least 12 months
• Statin therapy
• Beta-blockers
• ACE inhibitors (for indicated patients)
• Smoking cessation counseling
• Weight management
• Physical activity
• Diabetes management (goal HbA1c <7%)
• Blood pressure control (goal <140/90 mmHg or <130/80 mmHg for individuals with chronic kidney disease or diabetes)
• Cardiac rehabilitation referral 1

Common Pitfalls and Caveats

• Do not administer beta-blockers to hypotensive patients or those with signs of heart failure 1
• Avoid high-dose IV aspirin loading as it may increase in-hospital mortality 3
• Do not delay transfer to PCI-capable centers; bypass emergency departments when possible 1
• Suspect bleeding in any patient who is hypotensive after PCI or CABG, especially if on prasugrel 2
• For patients requiring warfarin, clopidogrel, and aspirin therapy, maintain INR of 2.0-2.5 with low-dose aspirin (75-81 mg) 4

The goal of STEMI management is to provide timely reperfusion with optimal antiplatelet and anticoagulant therapies to limit myocardial ischemia and infarct size, thereby reducing the risk of post-STEMI complications and heart failure 5, 6.