What is the treatment for 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 PCI cannot be performed within 120 minutes. 1

Initial Assessment and Immediate Management

• Obtain 12-lead ECG within 10 minutes of first medical contact
• Establish continuous ECG monitoring with defibrillator capacity immediately
• Administer loading doses of antithrombotic therapy:
  • Aspirin 162-325 mg (non-enteric coated, chewed) immediately
  • P2Y12 inhibitor loading dose (ticagrelor 180 mg, prasugrel 60 mg, or clopidogrel 600 mg)
  • Anticoagulation (unfractionated heparin, enoxaparin, or bivalirudin)

Reperfusion Strategy Algorithm

Primary PCI Strategy (Preferred)

• Implement when PCI can be performed within 90 minutes of first medical contact (target ≤60 minutes for high-risk patients) 1
• Transfer patients directly to PCI-capable centers, bypassing emergency departments when possible
• Immediate cardiac catheterization and intervention of the culprit artery

Fibrinolytic Strategy

• Implement when anticipated time from STEMI diagnosis to PCI exceeds 120 minutes 1
• Administer fibrinolytic therapy within 30 minutes of hospital arrival (door-to-needle time)
• Transfer to PCI-capable facility after fibrinolysis:
  • For high-risk patients: immediate transfer for early catheterization (within 24 hours)
  • For all other patients: transfer for routine catheterization within 24 hours 2

Time-Based Decision Making

• Patients presenting within 2 hours of symptom onset with excessive transfer delays should receive fibrinolytic therapy followed by immediate transfer for rescue PCI if needed 2
• Patients presenting 12-48 hours after symptom onset should not receive fibrinolysis but may benefit from urgent catheterization and revascularization 2

Adjunctive Pharmacotherapy

Antiplatelet Therapy

• Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor for at least 12 months after PCI 1
• Upstream clopidogrel treatment prior to arrival at catheterization lab is associated with reduced risk of death or MI 3

Anticoagulation

• For patients not receiving reperfusion therapy, low molecular weight heparin (LMWH) provides mortality benefit versus placebo 2
• Fondaparinux is contraindicated for primary PCI 1

Additional Medications

• Beta-blockers: Administer promptly in patients without contraindications (avoid in hypotensive patients or those with heart failure) 1
• ACE inhibitors: Start within 24 hours in patients with anterior STEMI, heart failure, or LVEF <40% 1
• Statins: Early use reduces both short and long-term adverse outcomes 2

Management of Special Populations

Late Presenters (>12 hours)

• For hemodynamically or electrically unstable patients or those with ongoing symptoms: Implement reperfusion-based strategy using primary PCI 2
• For stable late-presenting patients: Consider myocardial viability assessment to identify candidates for late mechanical reperfusion 2

Cardiogenic Shock

• Immediate transfer to PCI-capable centers is recommended regardless of time delays 2
• Early revascularization improves survival

Post-STEMI Care

• Monitor all patients for at least 24 hours after reperfusion therapy 1
• Cardiac rehabilitation referral
• Secondary prevention measures:
  • Continued DAPT for at least 12 months
  • Statin therapy
  • Beta-blockers
  • ACE inhibitors (for indicated patients)
  • Smoking cessation counseling
  • Weight management and physical activity

Common Pitfalls and Caveats

1. Delayed Reperfusion: Failure to recognize STEMI promptly or delays in activating the reperfusion pathway significantly worsen outcomes. Establish systems for rapid ECG acquisition and interpretation.

2. Inappropriate Reperfusion Strategy: Choosing fibrinolysis when timely PCI is available, or vice versa. Follow the time-based algorithm strictly.

3. Premature DAPT Discontinuation: Increases risk of stent thrombosis. Ensure patients understand the importance of medication adherence.

4. Overlooking Right Ventricular Infarction: Present with hypotension, clear lung fields, and elevated jugular venous pressure. Obtain right-sided ECG leads when inferior STEMI is suspected.

5. Underutilization of Early Transfer: Even after fibrinolysis, patients benefit from transfer to PCI-capable centers for early catheterization within 24 hours, rather than waiting for signs of failed reperfusion 2.

The evidence clearly demonstrates that a coordinated system for STEMI care with rapid access to primary PCI can prevent 6-8 events per 100 patients, potentially benefiting 35,000 patients per year in the US alone 2. Regional STEMI networks with standardized protocols for rapid diagnosis, transfer, and treatment are essential to optimize outcomes.