What are the management steps for ST-Elevation Myocardial Infarction (STEMI) and Non-ST-Elevation Myocardial Infarction (NSTEMI)?

Management Steps for STEMI and NSTEMI

The management of STEMI requires immediate reperfusion therapy with primary PCI within 120 minutes of diagnosis, while NSTEMI requires risk stratification followed by an early invasive strategy within 24 hours for high-risk patients. 1

STEMI Management

Immediate Actions (First 10 Minutes)

• Obtain 12-lead ECG within 10 minutes of first medical contact
• Establish IV access
• Administer:
  • Aspirin 162-325 mg (chewed or crushed) 1
  • P2Y12 inhibitor loading dose:
    • Ticagrelor 180 mg (preferred) or
    • Prasugrel 60 mg or
    • Clopidogrel 600 mg (if others unavailable) 1, 2
  • Anticoagulation with unfractionated heparin (UFH) bolus 60 IU/kg (max 4000 IU) 1

Reperfusion Strategy

1. Primary PCI (preferred if available within 120 minutes of diagnosis) 1

   • Transfer immediately to catheterization laboratory
   • Perform coronary angiography and PCI of infarct-related artery
   • Consider complete revascularization if cardiogenic shock is present
   • Administer GP IIb/IIIa inhibitors for high thrombus burden

2. Fibrinolysis (if primary PCI not available within 120 minutes) 1, 3

   • Administer within 10 minutes of STEMI diagnosis
   • Use fibrin-specific agent (e.g., tenecteplase, alteplase, or reteplase)
   • Anticoagulate with enoxaparin (preferred) or UFH
   • Transfer immediately to PCI-capable center after fibrinolysis
   • Perform rescue PCI if fibrinolysis fails (<50% ST resolution at 60-90 min)
   • Routine angiography within 2-24 hours after successful fibrinolysis

Post-Reperfusion Care

• Monitor for at least 24 hours for complications 1
• Initiate secondary prevention medications:
  • Continue DAPT (aspirin + P2Y12 inhibitor) for 12 months 1
  • High-intensity statin therapy 1
  • ACE inhibitor within 24 hours (especially for anterior MI, heart failure, or LVEF <40%) 1
  • Beta-blocker (oral) for patients with heart failure or LVEF <40% 1
  • Aldosterone antagonist for LVEF <40% with heart failure or diabetes 1

NSTEMI Management

Initial Assessment and Risk Stratification

• Obtain 12-lead ECG within 10 minutes of presentation
• Check cardiac biomarkers (troponin)
• Calculate TIMI or GRACE risk score
• Classify as high, intermediate, or low risk 1

Immediate Pharmacotherapy

• Aspirin 162-325 mg loading dose, then 75-100 mg daily 1
• P2Y12 inhibitor (ticagrelor or clopidogrel) 1, 2
• Anticoagulation with one of:
  • Enoxaparin (preferred) 1
  • UFH 1
  • Fondaparinux 1
  • Bivalirudin (for invasive strategy) 1

Management Strategy Based on Risk

1. Early Invasive Strategy (within 24 hours)

   • For high-risk patients with:
     • Recurrent angina/ischemia
     • Heart failure or hemodynamic instability
     • Arrhythmias
     • Dynamic ST-T changes
     • Elevated troponin 1

2. Delayed Invasive Strategy (within 25-72 hours)

   • For intermediate-risk patients 1

3. Conservative Strategy

   • For low-risk patients
   • Perform stress testing before discharge
   • If stress test positive → proceed to angiography
   • If stress test negative → medical therapy 1

Post-Angiography Management

• PCI selected: Continue aspirin, P2Y12 inhibitor, discontinue anticoagulant after uncomplicated PCI 1
• CABG selected: Continue aspirin, discontinue P2Y12 inhibitor (5-7 days for clopidogrel, 7 days for ticagrelor), continue UFH 1
• Medical therapy selected: Continue aspirin, P2Y12 inhibitor, and anticoagulant for duration of hospitalization (up to 8 days) 1

Key Differences Between STEMI and NSTEMI Management

1. Timing of Intervention:

   • STEMI: Immediate reperfusion (door-to-balloon <90 minutes)
   • NSTEMI: Risk-stratified approach (early invasive within 24 hours for high-risk)

2. Reperfusion Strategy:

   • STEMI: Primary PCI or fibrinolysis if PCI not available within 120 minutes
   • NSTEMI: No role for fibrinolysis; early invasive or conservative approach based on risk

3. Antiplatelet Therapy:

   • STEMI: More aggressive upfront loading and consideration of GP IIb/IIIa inhibitors
   • NSTEMI: Similar agents but timing may be delayed until coronary anatomy known

Common Pitfalls to Avoid

• Delayed recognition: Failure to obtain ECG within 10 minutes of presentation
• Inappropriate fibrinolysis in NSTEMI patients (contraindicated)
• Delayed transfer of STEMI patients to PCI-capable centers
• Underestimation of risk in NSTEMI patients leading to delayed intervention
• Inappropriate discontinuation of antiplatelet therapy
• Failure to initiate secondary prevention medications before discharge

Remember that during the COVID-19 pandemic, these pathways should still be followed with appropriate PPE and precautions to minimize viral transmission 1.