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

Management of ST-Elevation Myocardial Infarction (STEMI)

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

Initial Assessment and Immediate Management

• Immediate actions upon STEMI diagnosis:
  • Administer 162-325 mg of non-enteric coated aspirin (chewed) immediately 1
  • Add loading dose of P2Y12 inhibitor:
    • Preferred: Ticagrelor 180 mg or Prasugrel 60 mg
    • Alternative: Clopidogrel 600 mg 1
  • Start anticoagulation immediately:
    • Enoxaparin (preferred): 30 mg IV bolus followed by 1 mg/kg SC every 12 hours
    • Unfractionated heparin: 60 U/kg IV bolus followed by 12 U/kg/hour infusion
    • Bivalirudin: Alternative especially for patients with high bleeding risk 1
  • Administer supplemental oxygen if arterial saturation <90% 1
  • Consider morphine for pain and pulmonary congestion 1

Reperfusion Strategy Decision Algorithm

1. Can primary PCI be performed within 120 minutes of first medical contact?

   • YES → Proceed with primary PCI

     • For patients <75 years with large anterior infarction presenting within 2 hours, aim for PCI within 90 minutes 1
     • Transport directly to PCI-capable hospital with goal first medical contact-to-device time ≤90 minutes 1
     • Bypass emergency departments when possible to reduce door-to-balloon time 1

   • NO → Administer fibrinolytic therapy within 30 minutes of first medical contact

     • Use fibrin-specific agent (tenecteplase, alteplase, or reteplase) 1
     • Transfer patient immediately to PCI-capable center after fibrinolysis 1
     • Perform angiography and PCI of infarct-related artery 2-24 hours after successful fibrinolysis 1
     • Monitor for signs of failed fibrinolysis and be prepared for rescue PCI 1

Important Time Considerations

• Thrombolysis efficacy decreases significantly with time:
  • 51% mortality reduction when given within 1 hour of symptom onset
  • 20% reduction when given between 3-6 hours 1
  • Most beneficial within first 3 hours (approximately 30 early deaths prevented per 1000 patients) 1

Contraindications to Thrombolysis

• Prior intracranial hemorrhage
• Known cerebrovascular lesion
• Recent major trauma or surgery
• Active bleeding or bleeding diathesis
• Suspected aortic dissection 1

Post-Reperfusion Medical Therapy

• Before discharge, initiate:
  • Beta-blockers (start with low doses and titrate if heart failure present) 1
  • ACE inhibitors with low initial dose unless systolic BP <100 mmHg 1
  • Nitrates unless systolic BP <100 mmHg 1
  • Consider aldosterone blockade for patients with LVEF ≤0.40 and either symptomatic heart failure or diabetes 1
  • Consider diuretics if volume overload present 1
  • Discontinue NSAIDs (except aspirin) due to increased risks 1

Secondary Prevention

• Continue dual antiplatelet therapy for at least 12 months after PCI 1
• Maintain statin therapy, beta-blockers, and ACE inhibitors (for indicated patients) 1
• Provide smoking cessation counseling, weight management, and physical activity recommendations 1
• Refer to cardiac rehabilitation 1
• Manage diabetes (goal HbA1c <7%) and blood pressure (goal <140/90 mmHg or <130/80 mmHg for CKD/diabetes) 1

Special Considerations

• For patients presenting 12-24 hours after symptom onset, PCI may still be beneficial if signs of ischemia/viability in the infarct-related area are present 2
• Patients with transient STEMI (resolution of symptoms and ECG changes before reperfusion) still benefit from early invasive approach with intense medical therapy 3

Pitfalls to Avoid

• Delaying reperfusion therapy - outcomes worsen significantly with time
• Failing to transfer patients to PCI-capable centers after fibrinolysis
• Overlooking dose adjustments for anticoagulants in patients with renal insufficiency 1
• Administering GP IIb/IIIa inhibitors "upstream" rather than selectively for high intracoronary thrombus burden 2