What is the initial management for a patient presenting with ST-Elevation Myocardial Infarction (STEMI)?

Initial Management of ST-Elevation Myocardial Infarction (STEMI)

The initial management of STEMI requires immediate reperfusion therapy, preferably with primary percutaneous coronary intervention (PCI) when it can be performed within 90 minutes of first medical contact, or fibrinolytic therapy when PCI cannot be performed within 120 minutes.

Immediate Assessment and Stabilization

• Obtain a 12-lead ECG within 10 minutes of first medical contact and establish continuous ECG monitoring with defibrillator capacity immediately 1, 2
• Administer 162-325 mg of aspirin (non-enteric coated, chewed) immediately upon STEMI diagnosis 2
• Add a loading dose of a potent P2Y12 inhibitor:
  • Ticagrelor 180 mg or prasugrel 60 mg preferred (clopidogrel 600 mg if others unavailable) 1, 2
  • Note: Prasugrel is contraindicated in patients with prior stroke/TIA 3
• Start anticoagulation immediately (unfractionated heparin, enoxaparin, or bivalirudin) 2
• Administer supplemental oxygen only if oxygen saturation is <90% 1

Reperfusion Strategy Decision Algorithm

Primary PCI Strategy (Preferred)

• Implement when PCI can be performed within 90 minutes of first medical contact 1, 2
• Transfer patients directly to PCI-capable centers, bypassing emergency departments when possible 1, 2
• Target door-to-balloon time ≤90 minutes, with ≤60 minutes for high-risk patients 2

Fibrinolytic Therapy Strategy

• Implement when anticipated time from STEMI diagnosis to PCI exceeds 120 minutes 1, 2
• Administer within 30 minutes of hospital arrival (door-to-needle time) 2
• Use a fibrin-specific agent (tenecteplase, alteplase, or reteplase) 1
• Transfer to a PCI-capable center immediately after fibrinolysis 1

Post-Reperfusion Management

• Monitor all patients for at least 24 hours after reperfusion therapy 2
• Initiate beta-blockers in patients without contraindications (avoid in hypotensive patients or those with signs of heart failure) 1, 2
• Start ACE inhibitors within 24 hours in patients with anterior STEMI, heart failure, or LVEF <40% 1, 2
• Continue dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor for at least 12 months after PCI 1, 2
• Start high-intensity statin therapy as early as possible 1

Special Considerations

• Patients with cardiogenic shock should be immediately transferred to facilities capable of cardiac catheterization and rapid revascularization 1
• Patients with contraindications to fibrinolytic therapy should be brought immediately to PCI-capable facilities 1
• Right ventricular infarction presents with hypotension, clear lung fields, and elevated jugular venous pressure 2
• Avoid beta-blockers in hypotensive patients or those with signs of heart failure 1, 2
• Fondaparinux is contraindicated for primary PCI 1, 2

Common Pitfalls to Avoid

• Delaying ECG acquisition beyond 10 minutes of first medical contact
• Administering fibrinolytics to patients with contraindications (prior intracranial hemorrhage, known structural cerebral vascular lesions)
• Delaying transfer decisions for patients requiring primary PCI
• Premature discontinuation of DAPT, which increases the risk of stent thrombosis 2
• Administering routine oxygen to patients with normal oxygen saturation (≥90%) 1

The evidence strongly supports that minimizing time to reperfusion is critical for improving outcomes in STEMI patients. Every community should have a written protocol guiding emergency medical services in determining where to take patients with suspected or confirmed STEMI 1, with the goal of providing the most appropriate reperfusion strategy as quickly as possible.