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

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) is the recommended reperfusion strategy for all STEMI patients when it can be performed within 90 minutes of first medical contact by an experienced team. 1

Initial Assessment and Management

Immediate Actions (First 10 Minutes)

• Administer aspirin 162-325 mg (chewed) to all patients without contraindications 1
• Obtain 12-lead ECG within 10 minutes of presentation 1
• Establish IV access and administer oxygen if saturation <90% 1, 2
• Assess for hemodynamic stability and signs of cardiogenic shock
• Determine time of symptom onset (critical for reperfusion decisions)

Reperfusion Strategy Decision

The key decision point is whether timely primary PCI is available:

1. Primary PCI available within 90 minutes of first medical contact:

   • Preferred strategy for all STEMI patients 1
   • Transfer directly to catheterization laboratory, bypassing emergency department 1
   • Administer P2Y12 inhibitor loading dose:
     • Prasugrel 60 mg (preferred if no history of stroke/TIA) 1, 3
     • Ticagrelor 180 mg (alternative first choice) 1
     • Clopidogrel 600 mg (if prasugrel/ticagrelor unavailable or contraindicated) 1
   • Administer anticoagulation:
     • Unfractionated heparin (UFH): 70-100 U/kg IV bolus 1
     • Consider bivalirudin in patients with high bleeding risk 1

2. Primary PCI NOT available within 90 minutes (120 minutes maximum):

   • Administer fibrinolytic therapy within 30 minutes of first medical contact 1
   • Prefer fibrin-specific agents (tenecteplase, alteplase, or reteplase) 1
   • Add clopidogrel 300 mg (75 mg for age >75) 1
   • Anticoagulate with enoxaparin (preferred) or UFH 1
   • Transfer immediately to PCI-capable center for:
     • Rescue PCI if fibrinolysis fails (<50% ST resolution at 60-90 min) 1
     • Early routine PCI within 2-24 hours after successful fibrinolysis 1, 4

Management of Complications

Cardiogenic Shock

• Emergency revascularization (PCI or CABG) regardless of time from symptom onset 1
• Intra-aortic balloon pump counterpulsation for patients not responding to pharmacotherapy 1
• Consider mechanical circulatory support devices in refractory cases 1
• Avoid beta-blockers and calcium channel blockers 1
• Administer vasopressors for persistent hypotension after volume loading 1

Mechanical Complications

• Echocardiography to evaluate for ventricular septal rupture, papillary muscle rupture, or free wall rupture 1
• Urgent surgical repair for free wall rupture 1
• CABG at the same time as repair of mechanical complications 1

Adjunctive Pharmacotherapy

Antiplatelet Therapy

• Dual antiplatelet therapy (DAPT) for 12 months 1
  • Aspirin 75-100 mg daily indefinitely 1
  • P2Y12 inhibitor (prasugrel 10 mg, ticagrelor 90 mg BID, or clopidogrel 75 mg) 1
  • Consider prasugrel dose reduction (5 mg) for patients ≥75 years or <60 kg 3

Other Medications

• ACE inhibitors within 24 hours for anterior STEMI, heart failure, or EF ≤0.40 1
• Beta-blockers within 24 hours if no contraindications (avoid in acute heart failure) 1
• High-intensity statin therapy for all patients 1
• Aldosterone antagonist for patients with EF ≤0.40 and either symptomatic heart failure or diabetes 1

Post-STEMI Care

• Echocardiography to assess LV function and detect complications 1
• Implantable cardioverter-defibrillator for patients with sustained ventricular arrhythmias >48 hours post-STEMI (if not due to reversible causes) 1
• Cardiac rehabilitation program participation 1
• Smoking cessation counseling and support 1

Common Pitfalls to Avoid

• Delaying reperfusion therapy while waiting for laboratory results 1
• Using GP IIb/IIIa inhibitors routinely upstream before primary PCI 1
• Administering fibrinolytics to patients with contraindications or when primary PCI is readily available 1
• Failing to transfer patients after fibrinolysis for early angiography (pharmacoinvasive approach) 5, 6
• Delaying door-to-balloon time beyond 90 minutes in primary PCI 7
• Using NSAIDs for pain management due to prothrombotic effects 2

The management of STEMI requires a coordinated system of care with clear protocols to minimize time delays. Regional STEMI networks with established transfer protocols are essential to ensure timely reperfusion therapy for all patients, regardless of their initial presentation location 1, 7.