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

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) within 90 minutes of first medical contact is the gold standard treatment for STEMI patients, with fibrinolytic therapy indicated only when PCI cannot be performed within 120 minutes of diagnosis. 1

Initial Assessment and Management

Immediate Actions (First 10 Minutes)

• Obtain 12-lead ECG within 10 minutes of first medical contact 1
• Establish continuous ECG monitoring with defibrillator capacity immediately 1
• Administer loading dose of aspirin 162-325 mg (chewed) 2, 1
• Administer P2Y12 inhibitor loading dose 2, 1:
  • Preferred: Ticagrelor 180 mg or Prasugrel 60 mg (avoid prasugrel in patients ≥75 years or with history of stroke/TIA) 3
  • Alternative: Clopidogrel 600 mg (300 mg if ≥75 years)
• Start anticoagulation immediately 2, 1:
  • Unfractionated heparin (UFH): 70-100 U/kg IV bolus followed by infusion, or
  • Enoxaparin: 0.5 mg/kg IV bolus followed by SC dosing, or
  • Bivalirudin (for PCI)

Reperfusion Strategy Decision

1. Primary PCI (preferred strategy) 2, 1

   • Goal: First medical contact-to-device time <90 minutes
   • Direct transport to catheterization laboratory, bypassing emergency department when possible
   • Indicated for:
     • STEMI with symptoms <12 hours (Class I, Level A) 2
     • STEMI with contraindications to fibrinolysis regardless of time delay (Class I, Level B) 2
     • Cardiogenic shock or acute severe heart failure regardless of time delay (Class I, Level B) 2
     • Evidence of ongoing ischemia 12-24 hours after symptom onset (Class IIa, Level B) 2

2. Fibrinolytic Therapy 2, 1

   • Indicated when primary PCI cannot be performed within 120 minutes of STEMI diagnosis
   • Goal: Door-to-needle time <30 minutes
   • Administer fibrin-specific agent (tenecteplase, alteplase, or reteplase)
   • Contraindicated in:
     • Patients with ST depression except when true posterior MI is suspected or when associated with ST elevation in lead aVR (Class III: Harm, Level B) 2

Adjunctive Pharmacotherapy

Antiplatelet Therapy

1. Aspirin 2

   • Loading dose: 162-325 mg chewed or IV
   • Maintenance: 81 mg daily indefinitely (preferred over higher doses) (Class IIa, Level B) 2
   • If true aspirin allergy: clopidogrel 75 mg daily or ticlopidine 250 mg twice daily 2
   • Avoid ibuprofen as it blocks antiplatelet effects of aspirin (Class III) 2

2. P2Y12 Inhibitors 2, 3

   • For patients receiving fibrinolytic therapy:
     • Clopidogrel: 300 mg loading dose (<75 years) or 75 mg (≥75 years), then 75 mg daily for at least 14 days and up to 1 year 2
   • For patients undergoing PCI:
     • Continue therapy for at least 12 months with:
       • Clopidogrel: 75 mg daily
       • Prasugrel: 10 mg daily (5 mg if <60 kg) (avoid in patients ≥75 years or with history of stroke/TIA) 3
       • Ticagrelor: 90 mg twice daily

Anticoagulation

1. With Fibrinolytic Therapy 2

   • Continue for minimum 48 hours, preferably for duration of hospitalization (up to 8 days) or until revascularization
   • Options:
     • UFH: Weight-adjusted IV bolus and infusion to maintain aPTT 1.5-2.0× control
     • Enoxaparin: IV bolus followed by SC injections based on age, weight, and creatinine clearance
     • Fondaparinux: Initial IV dose, then daily SC injections (if creatinine clearance >30 mL/min)

2. With Primary PCI 2

   • UFH: Additional boluses as needed during procedure
   • Fondaparinux should not be used as sole anticoagulant for PCI (Class III: Harm) 2

Post-Reperfusion Management

Early In-Hospital Care

• Monitor for at least 24 hours after reperfusion therapy 1
• Perform routine echocardiography to assess LV/RV function and detect complications 1
• Low-risk STEMI patients who underwent successful PCI can be admitted directly to stepdown unit 1
• Limited mobility allowed after 12-24 hours if no recurrent ischemia, heart failure, or serious arrhythmias 1

Pharmacological Therapy

• Beta-blockers: Start early if no contraindications 1
• ACE inhibitors: Start within 24 hours in patients with anterior STEMI, heart failure, or LVEF <40% 1
• High-intensity statin therapy 1
• Dual antiplatelet therapy (DAPT) continuation:
  • With DES: Continue for at least 1 year 2
  • With BMS: Continue for at least 30 days and up to 1 year 2

Management of Complications

• Cardiogenic shock: Immediate transfer to PCI-capable hospital for coronary angiography (Class I, Level B) 2
• Ventricular septal rupture: Urgent cardiac surgical repair 1
• Right ventricular failure: Presents with hypotension, clear lung fields, and elevated jugular venous pressure 1

Special Considerations and Pitfalls

• Premature DAPT discontinuation increases risk of stent thrombosis 1
• Prasugrel contraindications: History of stroke/TIA, active bleeding, age ≥75 years (generally not recommended) 3
• Beta-blockers: Avoid in hypotensive patients or those with signs of heart failure 1
• Fondaparinux: Contraindicated as sole anticoagulant for primary PCI 1
• Timing of PCI after fibrinolysis: For failed reperfusion or reocclusion, urgent transfer for angiography and revascularization 2

Secondary Prevention

• Cardiac rehabilitation referral 1
• Smoking cessation counseling 2, 1
• Weight management and physical activity 2
• Long-term DAPT and statin therapy 1