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

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the recommended method of reperfusion for STEMI patients when it can be performed in a timely fashion by experienced operators within 90 minutes of first medical contact. 1

Initial Assessment and Triage

• Obtain 12-lead ECG within 10 minutes of first medical contact to confirm STEMI diagnosis 1
• Establish continuous ECG monitoring with defibrillator capacity immediately 1
• Administer supplemental oxygen if arterial saturation <90% 1
• Assess for contraindications to fibrinolysis (prior intracranial hemorrhage, known cerebrovascular lesion, recent major trauma/surgery, active bleeding) 1

Reperfusion Strategy Decision Algorithm

For PCI-Capable Facilities:

1. Move patient directly to catheterization laboratory, bypassing emergency department 2
2. Target door-to-balloon time <90 minutes (ideally <60 minutes for high-risk patients) 1
3. For patients presenting 12-24 hours after symptom onset, PCI is reasonable with evidence of ongoing ischemia 1

For Non-PCI-Capable Facilities:

1. If transfer to PCI-capable facility can be completed with first medical contact-to-device time ≤120 minutes (≤90 minutes for high-risk patients):

   • Immediate transfer for primary PCI 2, 1

2. If anticipated delay to PCI exceeds 120 minutes:

   • Administer fibrinolytic therapy within 30 minutes of first medical contact 2, 1
   • Transfer to PCI-capable facility after fibrinolysis for coronary angiography within 2-24 hours 2

3. For cardiogenic shock or severe heart failure:

   • Immediate transfer to PCI-capable facility regardless of time delay 1

Pharmacological Management

Antiplatelet Therapy

• Administer 162-325 mg aspirin (non-enteric coated, chewed) immediately upon STEMI diagnosis 2, 1
• Add loading dose of a potent P2Y12 inhibitor 2, 1:
  • Prasugrel 60 mg (preferred for primary PCI if no history of stroke/TIA) 3
  • Ticagrelor 180 mg (alternative)
  • Clopidogrel 600 mg (if prasugrel or ticagrelor unavailable or contraindicated)

Anticoagulation

• Start immediately with one of the following 2, 1:
  • Unfractionated heparin (UFH)
  • Enoxaparin
  • Bivalirudin (may be preferred in patients with high bleeding risk)

For Fibrinolytic Therapy

• Use a fibrin-specific agent (tenecteplase, alteplase, or reteplase) 2
• Continue anticoagulation until revascularization or for duration of hospital stay up to 8 days 2:
  • Enoxaparin IV followed by SC (preferred over UFH)
  • UFH as weight-adjusted IV bolus followed by infusion

Post-Reperfusion Management

Immediate Post-PCI Care

• Continue dual antiplatelet therapy (DAPT) for 12 months 2, 1:
  • Aspirin 75-100 mg daily plus
  • Prasugrel 10 mg daily (5 mg if ≥75 years or <60 kg) or
  • Ticagrelor or clopidogrel if prasugrel contraindicated

Supportive Care

• Perform echocardiography to assess LV/RV function and exclude mechanical complications 1
• Administer morphine sulfate for pain and pulmonary congestion 1
• Initiate beta-blockers within 24 hours unless contraindicated (hypotension, acute heart failure, AV block, severe bradycardia) 2, 1
• Start high-intensity statin therapy as early as possible 2
• Begin ACE inhibitors within 24 hours for patients with anterior infarct, heart failure, LV dysfunction, or diabetes 2
• Consider aldosterone blockade for patients with LVEF ≤40% and symptomatic heart failure or diabetes 1

Special Considerations

High Bleeding Risk

• Avoid prasugrel in patients with history of stroke/TIA or active pathological bleeding 3
• Consider reduced prasugrel dose (5 mg) in patients ≥75 years or <60 kg 3
• Add proton pump inhibitor for patients at high risk of gastrointestinal bleeding 2

Cardiogenic Shock

• Immediate transfer to PCI-capable facility regardless of time from symptom onset 1
• Emergency angiography and PCI if indicated 2

Secondary Prevention

• Continue DAPT for 12 months after PCI 2, 1
• Maintain statin therapy, beta-blockers, and ACE inhibitors long-term 1
• Refer to cardiac rehabilitation 2, 1
• Provide smoking cessation counseling and support 2
• Manage diabetes (goal HbA1c <7%) and blood pressure (<140/90 mmHg) 1

Pitfalls and Caveats

• Premature discontinuation of DAPT increases risk of stent thrombosis, MI, and death 3
• NSAIDs (except aspirin) should be discontinued due to increased risks of mortality, reinfarction, and heart failure 1
• Avoid beta-blockers in patients with hypotension, acute heart failure, or severe bradycardia 2
• The efficacy of fibrinolysis decreases significantly with time, with greatest benefit when given within 1 hour of symptom onset 1
• Fibrinolysis carries risks including stroke (3.9 per 1000 patients) and intracranial hemorrhage (0.5%) 1

The management of STEMI requires rapid decision-making and coordination between emergency services and cardiac care teams. The evidence strongly supports primary PCI as the preferred reperfusion strategy when timely access is available, with fibrinolysis followed by transfer for PCI as a reasonable alternative when PCI is not readily accessible.