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

Management of ST-Elevation Myocardial Infarction (STEMI)

Primary percutaneous coronary intervention (PCI) should be performed within 90 minutes of first medical contact for all STEMI patients when available, or fibrinolytic therapy should be administered within 30 minutes if timely PCI is not feasible. 1

Initial Assessment and Diagnosis

• Obtain 12-lead ECG within 10 minutes of first medical contact (FMC) 1, 2
• Establish continuous ECG monitoring with defibrillator capacity immediately 1
• For inferior STEMI, obtain right-sided ECG leads (V3R, V4R) to assess for right ventricular involvement 2
• Order cardiac biomarkers (troponins) but do not delay reperfusion therapy awaiting results 2
• Administer immediate pharmacotherapy:
  • Aspirin 162-325 mg (chewed) 1, 2
  • P2Y12 inhibitor loading dose: preferably ticagrelor 180 mg or prasugrel 60 mg (or clopidogrel 600 mg if others unavailable) 1, 2

Reperfusion Strategy Decision Algorithm

Primary PCI Strategy (Preferred)

• Indicated for all patients with symptoms of ischemia ≤12 hours duration and persistent ST-segment elevation 1
• Time targets:
  • FMC-to-device time ≤90 minutes for direct presenters 1
  • FMC-to-device time ≤120 minutes for transfers 1
• Direct transport to catheterization laboratory, bypassing emergency department when possible 1
• Anticoagulation options:
  • Unfractionated heparin (UFH) with dose adjusted based on GP IIb/IIIa inhibitor use 2
  • Bivalirudin (preferred in high bleeding risk patients) 2
  • Fondaparinux is NOT recommended for primary PCI 1

Fibrinolytic Strategy (When PCI is not timely available)

• Administer when primary PCI cannot be performed within 120 minutes of FMC 1
• Use a fibrin-specific agent (tenecteplase, alteplase, or reteplase) 1, 2
• Door-to-needle time goal: <30 minutes 1, 2
• Anticoagulation required:
  • Enoxaparin IV followed by SC (preferred over UFH) 1, 2
  • OR UFH as weight-adjusted IV bolus followed by infusion 1, 2
• Transfer to PCI-capable center immediately after fibrinolysis 1, 2
• Assess for reperfusion success (≥50% ST-segment resolution at 60-90 min) 1

Post-Fibrinolysis Management

• If fibrinolysis successful: Perform angiography and PCI of infarct-related artery between 2-24 hours 1, 2
• If fibrinolysis failed (<50% ST resolution) or patient unstable: Immediate rescue PCI 1
• Emergency angiography and PCI indicated for patients with heart failure/shock 1

Special Considerations

Cardiogenic Shock

• Immediate transfer to PCI-capable facility for patients with cardiogenic shock 1
• Primary PCI is strongly preferred over fibrinolysis 1

Late Presenters (12-24 hours)

• Primary PCI is reasonable for patients with:
  • Severe heart failure 1
  • Hemodynamic or electrical instability 1
  • Persistent ischemic symptoms 1

Post-Cardiac Arrest

• Primary PCI strategy recommended for resuscitated cardiac arrest patients with ECG consistent with STEMI 1
• Targeted temperature management indicated for unresponsive post-arrest patients 1

Post-STEMI Care

• Dual antiplatelet therapy (DAPT) for 12 months 1, 2, 3
• High-intensity statin therapy as early as possible 2
• Beta-blockers if no contraindications 2
• ACE inhibitors within 24 hours for anterior STEMI, heart failure, or LVEF <40% 2
• Echocardiography during hospital stay to assess ventricular function and detect complications 2
• Monitor for at least 24 hours after reperfusion therapy 2

Common Pitfalls to Avoid

1. Delays in ECG acquisition: Ensure ECG is obtained within 10 minutes of FMC 1
2. Inappropriate oxygen administration: Routine oxygen not recommended in patients with SaO2 ≥90% 1
3. Failure to recognize right ventricular involvement: Always obtain right-sided ECG leads in inferior STEMI 2
4. Delaying reperfusion for laboratory results: Do not wait for cardiac biomarkers to initiate reperfusion 2
5. Inappropriate use of fondaparinux: Not recommended for primary PCI 1
6. Failure to transfer post-fibrinolysis: All patients should be transferred to PCI-capable centers after fibrinolysis 1, 2

The most recent evidence emphasizes the importance of regional STEMI care networks designed to deliver reperfusion therapy expeditiously, with efforts to make primary PCI available to as many patients as possible 1. Time is critical, and systems should be designed to minimize delays at every step of the process.