What is the management of 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 a target of ≤60 minutes for high-risk patients. 1

Initial Assessment and Management

• Obtain 12-lead ECG within 10 minutes of first medical contact
• Establish continuous ECG monitoring with defibrillator capacity immediately
• Administer:
  • Aspirin 162-325 mg (non-enteric coated, chewed) immediately
  • Loading dose of P2Y12 inhibitor:
    • Preferred: Ticagrelor 180 mg or Prasugrel 60 mg
    • Alternative: Clopidogrel 600 mg (if others contraindicated)
  • Anticoagulation: Unfractionated heparin, enoxaparin, or bivalirudin
• Avoid oxygen administration in patients with normal oxygen saturation (SaO2 ≥90%) as it may be harmful 1

Reperfusion Strategy Decision Algorithm

Primary PCI (Preferred Strategy)

• Indicated when PCI can be performed within 90 minutes of first medical contact 1
• Transfer patients to PCI-capable centers, bypassing emergency departments when possible
• Consider complete revascularization (non-infarct related arteries) during index procedure
• Contraindications for prasugrel: active bleeding, history of TIA/stroke, or high bleeding risk 2

Fibrinolytic Therapy

• Indicated when anticipated time from STEMI diagnosis to PCI exceeds 120 minutes 1, 3
• Administer within 30 minutes of hospital arrival (door-to-needle time)
• Use fibrin-specific agents (tenecteplase, alteplase, or reteplase)
• Required anticoagulation with fibrinolysis:
  • Enoxaparin IV followed by SC, or
  • UFH as weight-adjusted IV bolus followed by infusion
• After fibrinolysis:
  • Transfer all patients to a PCI-capable center
  • Perform rescue PCI immediately if fibrinolysis fails (<50% ST-segment resolution at 60-90 minutes)
  • If successful, perform routine coronary angiography within 3-24 hours 1

Post-Reperfusion Management

Antiplatelet Therapy

• Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor for at least 12 months after PCI 1
• For patients <60 kg on prasugrel, consider lowering maintenance dose to 5 mg (from standard 10 mg) due to increased bleeding risk 2
• Avoid premature discontinuation of DAPT as it increases risk of stent thrombosis 1

Additional Pharmacotherapy

• Beta-blockers: Administer early if no contraindications (avoid in hypotensive patients or those with signs of heart failure) 1
• ACE inhibitors: Start within 24 hours in patients with anterior STEMI, heart failure, or LVEF <40% 1
• High-intensity statin therapy: Initiate or continue in all patients without contraindications 4
• Obtain fasting lipid profile within 24 hours of presentation 4

Management of Complications

Cardiogenic Shock

• Emergency revascularization with either PCI or CABG is recommended regardless of time delay from MI onset 4
• Consider intra-aortic balloon pump counterpulsation for patients who don't quickly stabilize with pharmacotherapy 4
• Alternative LV assist devices may be considered in refractory cardiogenic shock 4

Recurrent Ischemia

• Escalate medical therapy with nitrates and beta-blockers
• Initiate intravenous anticoagulation if not already done
• For patients with hemodynamic instability, poor LV function, or large area of myocardium at risk, refer urgently for cardiac catheterization 4

Pericarditis

• Administer acetaminophen, colchicine, or narcotic analgesics if aspirin is ineffective
• Avoid glucocorticoids and NSAIDs as they are potentially harmful 4

Special Considerations

• For patients requiring CABG:

  • Aspirin should not be withheld before urgent CABG
  • Discontinue clopidogrel or ticagrelor at least 24 hours before urgent on-pump CABG if possible
  • Discontinue short-acting GP IIb/IIIa receptor antagonists at least 2-4 hours before urgent CABG 4

• For patients with ventricular arrhythmias:

  • Implantable cardioverter-defibrillator therapy is indicated before discharge in patients who develop sustained ventricular tachycardia/fibrillation more than 48 hours after STEMI (if not due to transient causes) 4

Secondary Prevention

• Cardiac rehabilitation referral
• Smoking cessation counseling
• Weight management and physical activity (minimum 30 minutes 3-4 days per week)
• Diabetes management (goal HbA1c <7%)
• Blood pressure control (goal <140/90 mmHg or <130/80 mmHg for individuals with chronic kidney disease or diabetes) 4

The management of STEMI requires rapid assessment and decision-making to ensure timely reperfusion. The evidence strongly supports primary PCI as the preferred strategy when available within appropriate timeframes, with fibrinolytic therapy as an alternative when PCI cannot be performed promptly. Post-reperfusion care and secondary prevention are crucial for improving long-term outcomes and reducing the risk of recurrent events.